Sunday 8AM Update
Out on Pensacola Beach we have partly cloudy skies with a 20% chance of storms today. Wind is out of the south southwest blowing around 5-10 mph then then increasing throughout the day. Surf is up running in the waist to chest high range with some bigger sets. Waves will be up all day, then will drop tomorrow as winds switch offshore.
Low @ 02:03 AM -0.21 ft. High @ 3:42 PM 1.29 ft.


Well, almost, it did a little this past Friday. Death Valley only receives 2 inches per year, mostly in the winter. In a lot of locations in this world, you can receive 2 inches of rain in less than an hour. The storm clouds gave Death Valley National Park a look I normally don’t see. The clouds and filtered sunlight produced some memorable images.


Posted at 8:52 AM on April 10, 2008
by Julia Schrenkler
So, there's a major winter storm coming our way. It looks like it will rain on gardening plans, folks will have to face the wind in their finest outfits when attending events, and the storm will cover spring fever symptoms with snow.
Keep up on the storm via Updraft, MPR's Weather blog.


|The trails of precipitation that emerge from the base of generating cells typically observed on time-height displays from vertically pointing radars. (Also called streamers.) Snow trails are also commonly observed on range-height indicator displays. Snow trails emerge from a layer of convective instability that often exists in the middle or upper troposphere in widespread storms. Small convective cells developing within this layer produce the ice crystals that then fall to lower altitudes. The base of the convectively unstable layer is called the snow- generating level. The shape and vertical extent of the streamers depend on the vertical profiles of wind and relative humidity in the layer through which the precipitation falls.


Marko Korosec is a storm chaser who puts his life in the line every time he takes pictures of supercell thunderstorms. Supercell thunderstorms are tornado-generating, hail-producing, cloud formations that may easily be mistaken as an alien invasion. Marko, who originally hails from Slovenia, took these awesome pictures during a month-long expedition into the U.S.A’s tornado alley. When not chasing superstorms, Marko also captures lightning strikes. During an interview on Daily Mail, he said: “I usually observe storms in as safe a position as possible, to avoid any dangerous conditions which could cause us damage or to the vehicle. Storm chasing usually means a lot of moving around, remaining in one position for some time and then moving when storm gets closer.”
See more of his work.


A network of organisations including businesses, charities, educational institutions and many others from across Southampton are forming a partnership called Southampton Clean Air Network (CAN).
Together this group is committed to doing what it can to reduce levels of air pollution in the city through changes in personal and organisational actions, encouraging all those who they meet and do business with to do the same, and by actively supporting each other to find ways that help to improve air quality in the city.
The Clean Air Network believes that Southampton CAN make a big difference to air quality! You can join the Clean Air Network here.
CAN is co-facilitated by the Environment Centre (tEC) and Southampton City Council.


Heavy Lake Effect Snow Through Wednesday; Heavy Rain Across Hawaii
Heavy lake effect snow will continue downwind of the Great Lakes through Wednesday morning. Expect difficult travel conditions. The cold air has finally made its way south and east, making way for near to below freezing low temperatures. Meanwhile, a low pressure system moving northwest of Hawaii will bring thunderstorms, heavy rain and flooding potential across the state Wednesday.
|NWS Forecast for: Coastal waters from Pt. St. George to Cape Mendocino CA out 10 nm (PZZ450)|
Issued by: National Weather Service Eureka, CA
Last Update: 851 PM PST Tue Nov 28 2023
|Tonight: E winds 5 kt. Waves W 5 ft at 12 seconds. Slight chance of showers. |
Wed: N winds 5 to 10 kt. Waves SW 2 ft at 8 seconds...and W 5 ft at 12 seconds.
Wed Night: NE winds 5 to 10 kt. Waves SW 3 ft at 8 seconds...and W 3 ft at 11 seconds.
Thu: SW winds 5 to 10 kt. Waves NW 5 ft at 13 seconds.
Thu Night: N winds 5 to 10 kt. Waves NW 7 ft at 12 seconds...and W 2 ft at 16 seconds.
Fri: S winds 10 to 20 kt. Waves NW 9 ft at 12 seconds.
Sat: S winds 10 kt. Waves NW 11 ft at 14 seconds.
Sun: S winds 10 to 15 kt. Waves NW 10 ft at 14 seconds...and NW 3 ft at 20 seconds.
|Zone Forecast: Coastal waters from Pt. St. George to Cape Mendocino CA out 10 nm (PZZ450)|
Visit your local NWS office at: https://www.weather.gov/eka


Flood warnings remain in place for Wyandotte County as water entering the Missouri River in the Dakotas makes it way to the Kansas City area this week.
Dry conditions today will not compound local river flooding through Friday, however, water from levee breaches re-entering the river upstream may aggravate already swollen and flooding rivers and streams, according to the National Weather Service. Areas upstream from Kansas City, including St. Joseph, Missouri, Atchison, Kansas, and Leavenworth, Kansas, are continuing to flood.
The rivers here now are expected to crest on Saturday, according to hydrology charts. Local emergency officials have stated that no residences in Wyandotte County are expected to be flooded.
It was 39 degrees at 9 a.m. Thursday, with a high of 58 expected, the weather service said.
Weekend rainfall here from a quarter-inch to a half-inch are not expected to affect flooding, according to officials.
The flood warning for the Missouri River above Parkville, Missouri, which includes Wyandotte County, will be in effect until Friday, March 29, according to the weather service. The river is currently in moderate flood stage, and is expected to crest on Saturday. The Wolcott levees in western Wyandotte County are at risk.
According to the weather service, the river above Parkville was 30.2 feet at 8:45 p.m. Wednesday, and 30.47 feet at 7:45 a.m. Thursday. It is projected to rise to almost 33.7 feet by Saturday morning. The Wolcott levee sections could overtop at 32 feet and 32.5 feet.
The river above Parkville is projected to fall below flood stage on Thursday, March 28, before midnight, according to the weather service.
Wyandotte County also will be under a minor flood warning for the Kansas River at 23rd Street from Friday morning to late Sunday night, according to the weather service. This river gauge is at the east side of Kansas City, Kansas, on Kansas Avenue at the state line, connecting with Kansas City, Missouri, near the American Royal.
At 8:45 p.m. Wednesday, the Kansas River stage at 23rd was 31.4 feet, and it was 31.55 feet at 7:45 a.m. Thursday, with flood stage at 33 feet. The river is expected to crest at 33.7 feet by Saturday morning. At 33 feet, undeveloped woodland along the river and outside of levee protection is flooded, with no flooding expected behind the levees.
A minor flood warning also has been issued for Wyandotte County from Friday evening to Sunday evening for the Missouri River at Kansas City, according to the weather service. This river gauge is south of the downtown Kansas City, Missouri, airport, near the City Market, and not far from the state line. It is not far from the Kaw Point area.
The river at this point was at 29.5 feet at 8:30 p.m. Wednesday, and 29.73 feet at 7:30 a.m. Thursday. It was projected to rise to nearly 32.2 feet by Saturday morning. At this point, flood stage is 32 feet. At 32 feet, minor flooding outside the levees occurs.
Residents are warned not to drive through flowing water. Nearly half of all flood fatalities are vehicle related, according to the weather service. As little as 6 inches of water may cause you to lose control of your vehicle. Two feet of water will carry most vehicles away.
For more weather information, visit www.weather.gov/kc/.
Today, expect sunny skies with a high near 58 and a north northwest wind of 5 to 8 mph, the weather service said.
Tonight, it will be clear, with a low of 34 and a north wind of 5 mph becoming light and variable, according to the weather service.
Friday, it will be sunny with a high near 61, and light and variable wind becoming east northeast 5 to 7 mph in the morning, the weather service said.
Friday night, it will be partly cloudy, with a low of 38 and an east northeast wind of 7 mph, according to the weather service.
Saturday, showers are likely, with a 70 percent chance of precipitation mainly after 1 p.m., the weather service said. It will be mostly cloudy with a high near 56 and a southeast wind of 7 to 10 mph.
Saturday night, there is a 60 percent chance of showers, with thunderstorms also possible after 1 a.m., according to the weather service. It will be cloudy, with a low of 48. New rainfall amounts of between a tenth and quarter-inch are possible.
Sunday, there is a 50 percent chance of showers and thunderstorms, with a high near 64, the weather service said.
Sunday night, there is a 30 percent chance of showers, with a low of 45, according to the weather service.
Monday, there is a 40 percent chance of showers, with a high near 53, the weather service said.
Monday night, it will be mostly cloudy, with a low of 33, according to the weather service.
Tuesday, it will be sunny, with a high near 53, the weather service said.
Tuesday night, it will be mostly clear, with a low of 40, according to the weather service.
Wednesday, it will be mostly sunny, with a high near 63, the weather service said.
To see an earlier story, visit http://wyandottedaily.com/flood-warnings-in-place-for-wyandotte-county-homes-not-expected-to-be-in-any-danger/.


Rain and snow. Low around 32. South wind 7 to 9 mph. Chance of precipitation is 90%. Total nighttime snow accumulation of less than a half inch possible.
Rain and snow before 2pm, then rain between 2pm and 4pm, then rain and snow after 4pm. High near 36. South wind 5 to 8 mph. Chance of precipitation is 90%. New snow accumulation of less than a half inch possible.
Snow. Low around 31. Light and variable wind becoming northwest around 6 mph after midnight. Chance of precipitation is 90%. New snow accumulation of 1 to 3 inches possible.
Access the Fulton Public Schools Facebook page by searching Fulton Public Schools.
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The Fulton Public Schools APP is powered by Parentlink. On your mobile device, go to the app store or to Google Play to download. Search for Fulton Public Schools and it's FREE! Get the latest on important dates, calendars, . . .


Today's weather in London, Tuesday June 6
Today is expected to start cloudy with sunny spells and a minimum of 9.6°C. By the afternoon, the sky will be mostly clear with a maximum of 22.7°C. The average for the day is 14.6°C.
Tomorrow, the day will start with a clear sky and a minimum of 8.1°C. As the day progresses, it will be sunny with a maximum of 23.6°C in the afternoon. The average for the day stands at 15.5°C.
In the next few days, we can expect sunny days with clear skies. The maximum will range from 23.1°C to 23.6°C, while the minimum temperatures will be between 8.5°C and 9.6°C. The average temperatures will vary between 15.5°C and 15.6°C, ensuring a pleasant and comfortable environment for the coming days.
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A storm forming off the Northeast U.S. coast tonight will brush Nova Scotia with some snow late tonight through midday Tuesday. The highest accumulations will run along the south coast and up toward Cape Breton.
The storm will then take aim at Newfoundland Tuesday through Tuesday evening with significant snowfall across the southern half.
Lake-effect snow will be an issue for some as the coldest air of the season crosses the lakes. It's a very tough forecast as winds will be constantly shifting and there will also be a surface trough laying WNW to ESE from Lake Huron into New England that will also focus a band of heavier snow.
The map below shows the snowfall forecast valid from this evening through Tuesday. This does not include snow from earlier today. There will be additional rounds of lake-effect snow into the middle of the week.
My best estimate at this time is that there will be a narrow band of heavier snow setting up somewhere from the Bruce Peninsula through the Owen Sound area then to near Collingwood later tonight.
After 4 a.m. or so, that band will weaken and a second lake-effect band sets up somewhere near Saugeen Shores and perhaps extending into the Hanover/Mt. Forest area into the morning then slowly shifts south toward Kincardine and over to Listowel. Under this band the snow could be quite heavy with dangerous travel conditions. Again, very tough forecast to pinpoint these bands through tomorrow.
The map below shows how cold it will feel (on average) during the afternoon Tuesday after you factor in the wind and other elements.
Temperature departures (F) for Thursday morning
Midweek clipper storm
A classic Alberta clipper will dive southeastward Wednesday and will bring accumulating snow from northern Alberta (Wed) through southern Sask. (Wed night) into southern Manitoba (Thu). Look for a general 6-12 cm with this feature.
This same feature could spawn another coastal storm later in the week, perhaps leading to the possibility of significant snow from eastern New England through Nova Scotia Friday night and Saturday.
Keep in mind, you can also follow me on twitter @BrettAWX
Comments that don't add to the conversation may be automatically or manually removed by Facebook or AccuWeather. Profanity, personal attacks, and spam will not be tolerated.
Late-season snow for the western Prairies later this week and a look at the weekly long range pattern.
Major storm to inundate eastern Canada with rain and wind Thursday followed by a change to snow later Thursday night into Friday.
My latest thoughts on the weather pattern into next week


As the weather forecast looked rather bad for the rest of the week, we planned an imaging session of comet Garradd on Sunday night. We also wanted to test out some new equipment and modifications to the AstroTrac. Conditions were pretty average; temperatures around freezing, but a lot of humidity in the air caused the sky background to be very light. Not too good for comet photography. The comet was also located in the eastern part of the sky that suffers from severe light pollution from the city of Deventer. Nevertheless, the comet was easily visible in binoculars (8.5×42). We both used our AstroTrac’s with various Canon camera’s and lenses to photograph the comet. I also used the observatories 30 cm Newton telescope for some close-ups of the nucleus. When we packed up our stuff, everything was covered in a thin layer of ice.


Dreams of a white Christmas may come true in several areas of France, as - after a relatively mild and wet start to the week - winter is forecast to strike on Christmas Eve, with temperatures expected to drop by up to 10C in 24 hours.
Rain and strong winds from the north and west of the country will spread east on Monday, forecasters have said - and heavy rain will dominate in the north on Tuesday and Wednesday, and may lead to localised flooding.
Further south, however, conditions will appear quite spring-like, with temperatures closer to April norms than December - though winds will begin to pick-up in Mediterranean areas, bringing grey skies to the south coast.
Christmas Eve, however, will see a sharp drop in temperatures, with winds now coming from the north, bringing rain showers to much of the country. Snow is possible even at lower altitudes in central and eastern regions.
Christmas Day is expected to be wintry in all mountain areas, with snow and sleet widely forecast from the north to the Auvergne-Rhône-Alpes. Temperatures are expected to rise no higher than 2 and 3C, the norm for the time of year.


A lot of meteorology can be spotted on the satellite image below (courtesy of Meteocentre.com).
A mature depression is situated over the Baltic, whilst a long trailing cold front extends back across central Europe toward Iberia.
There are some speckled convective showers over the northern North Sea, whilst a small frontal system encroaches into western Britain.
To our west, a developing depression is sending a shield of high cloud ahead of it, advancing toward Britain associated with a strong jet stream aloft.
This will wind itself up into a strong storm system tonight, bringing severe gales to northern Britain.
A cold front will advance south across Britain tomorrow, and wintry showers will follow, so the satellite image will change again as our weather remains in a changeable mood.


11:15 AM - 11:30 AM
[SSS10-15] Monitoring the intensity of a hurricane (typhoon) by seismic signals
Keywords:seismic signals from tropical cyclone, Seismic noise, Hurricane and typhoon
In this study, we take an example of Hurricane Patricia in 2015 which was the strongest hurricane on record in the eastern North Pacific and North Atlantic basins (Kimberlain et al., 2016). We examine the nature of seismic waves that were excited as the hurricane intensified over anomalously warm waters to the south of Mexico and then reached land near Playa Cuixamala (Oct. 23, 23th hour, UTC). This landfall area was surrounded by many seismic stations from the Mexican National Seismological Service (SSN) which has broadband seismic data (STS-2 type velocity sensors).
We examined temporal variation of power spectral density (PSD) of seismic data for selected 32 stations using the time-frequency plots. The landfall occurred near the center of 32 stations and depending on the distance from the hurricane, we can categorize the characteristics of time-frequency plots into three types, the northern group, the central group, and the southern group. Stations in the central group recorded the time evolution of hurricane intensity most faithfully and for monitoring purposes, we should focus only on these stations. The southern group showed signals from the hurricane but it also showed strong effects of nearby coastal (trapped) waves which made it problematic for monitoring purposes. The northern group seems too far away in general as seismic signals from the hurricane became much weaker.
This hurricane developed from category 1 to category 5 within 24 hours on Oct. 22, 2015, while it was off the coast about 350-400 km; the data in the central group shows a rapid increase of seismic energy around 0.15 Hz (between 0.1 and 0.2 Hz) which matches with intensification of wind speeds of this hurricane. This frequency band is similar to those of secondary microseisms. The integrated power between 0.1 and 0.3 Hz shows a sudden increase of power during the first 6 hours of Oct. 22 and remains at this high level for about a day when the hurricane was the strongest. Seismic amplitudes decay from the coastal stations to the interior, suggesting (obviously) that coastal stations are critical for monitoring purposes.
The data in the central group showed a rapid increase of seismic energy for higher frequencies up to 1 Hz too, although the maximum energy was at about 0.15 Hz. We also noted that there were no significant changes in seismic data below 0.1 Hz.
These observations indicate that we should examine the frequency band from about 0.1 Hz to 0.4 Hz focusing mainly on the stations within about 500 km from the hurricane center. Since the location of hurricane is critical, seismic monitoring has to be conducted together with satellite data.


Revista Española de Salud Pública
Print version ISSN 1135-5727
CAMBRA CONTIN, Koldo and ALONSO FUSTEL, Eva. The short-term impact of air pollution on the mortality. results of the EMECAM project in the metropolitan area of Bilbao. Rev. Esp. Salud Publica [online]. 1999, vol.73, n.2, pp.209-214. ISSN 1135-5727. http://dx.doi.org/10.1590/S1135-57271999000200010.
BACKGROUND: The objective of this study was to assess the short-term impact of air pollution with Sulfur Dioxide (SO2), Total Suspended Particles (TSP), Nitrogen Dioxide (NO2) and Black Smoke (BS) on the daily number of deaths in the Metropolitan Area of Bilbao. METHODS: The EMECAM project protocol was followed. RESULTS: Increases in TSP, in both maximum hourly figures and daily averages, are significantly associated with increases in the daily number of deaths from all causes, from circulatory causes and from all causes among those older than 70. No differences between six-month periods were found. NO2 average levels were associated with daily mortality from respiratory causes in the entire period and during the warm season, and from all causes among those older than 70 in the cool months. CONCLUSIONS: TSP levels are associated with daily mortality in the Metropolitan Area of Bilbao. The relationship between NO2 and the number of deaths from respiratory causes, very high in the warm season, needs further research to assess its independence.
Keywords : EMECAM Project; Mortality; Air pollution; Particles; Nitrogen dioxide; Poisson regression.


|Brisbane. Image from ABC news.|
Last year was the world's wettest on record. And it ties with 2005 as the hottest year since record-keeping began. Beside the floods we're seeing in Queensland, there's flooding now in Brazil that has killed at least 430 people. There've been massive recent floods in Pakistan, California and Tennessee. Russia saw a record breaking summer heatwave and there were snowstorms across US and Europe. This is what climate change looks like.
Experts say Queensland's flood disaster is the result of a La Nina weather pattern and global warming. The El Nina effect results in higher sea temperatures and heavy rain.
When people are directly affected by something, when they feel things personally, they act. So while I was at the shop the other day and every shop-keeper mentioned the tragedy my comment is also about climate change. "This is what climate change looks like."
Click here to donate to the Queensland flood relief.


Variable clouds with temperatures steady near the upper 20s. Winds WSW at 15 to 20 mph. Hourly Details
Mostly cloudy with snow showers during the morning. High 31F. Winds WSW at 10 to 20 mph. Chance of snow 40%.
Some clouds. Low 26F. Winds SSW at 10 to 20 mph.
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Meteorologists at Freie Universität Identify Cause of Cold and Warm Periods during Winter
New Research on Stratospheric Warmings Highlighted in “Nature Geoscience”
№ 13/2011 from Jan 17, 2011
Meteorologists at Freie Universität have found a correlation between warming in the stratosphere and cold or warm winter periods. They observed that there is an increased number of stratospheric warmings, when the heat flow from the North Atlantic into the atmosphere is increased. Trends for winter temperatures can be derived from these new findings. “This could mean that in Europe there will increasingly be periods lasting several decades with predominantly colder winters alternating with periods of warmer winters,” says Semjon Schimanke, who led the research. The meteorologists expect that in the long term their research will help weather forecasters make more accurate predictions.
The phenomenon of stratospheric warming was first discovered in 1952 by Professor Richard Scherhag at the Institute of Meteorology, Freie Universität Berlin. It appeared in the scientific literature as the “Berlin phenomenon.” In the meantime, these events are referred to as “sudden stratospheric warmings,” and 30 have been registered so far.
On average, sudden stratospheric warmings occur in every second winter, and they are very unevenly distributed over the observation period. Only a single stratospheric warming occurred between the winters of 1988/1989 and 1997/1998, while nine have been registered since the beginning of this millennium. So far there has been no explanation. With their new research, the meteorologists at Freie Universität have shown that the intermittent sudden stratospheric warmings are a consequence of the interaction between the North Atlantic, the troposphere, and the stratosphere. They found that an increased number of sudden stratospheric warmings occur when the heat flux from the North Atlantic into the atmosphere is increased.
During the winter months in the lower polar stratosphere, which lies approximately 20 kilometers above the Earth’s surface, temperatures on average are below minus 70 degrees Celsius. The cold temperatures are combined with strong westerly winds that form the southern boundary of the so-called stratospheric polar vortex. This dominant structure is disrupted in some winters or even reversed. Under these conditions the temperatures in the lower stratosphere rise within a few days by more than 50 degrees, and the polar region is warmer than southerly latitudes. This implies a reversal in the west-east winds and the collapse of the polar vortex. Using models and observations, it was possible to show that such sudden stratospheric warmings are initially excited from the troposphere, but then also have a strong influence on tropospheric circulation.
After a sudden stratospheric warming, among other things the differences in pressure between the Icelandic Low and the Azores High are reduced. This pressure difference determines the prevailing wind direction for Central Europe and thus determines whether the European winter turns cold or warm. Thus, for example, the 2009/2010 winter was characterized by a highly disturbed polar vortex, and in many parts of the Northern Hemisphere there was a severe and snowy winter.


The lines of evidence that humans are raising CO2 levels
What the science says...
Every year humans release about 30 billion tons of carbon dioxide (CO2) into the atmosphere through the burning of fossil fuels, such as coal and oil. This is causing the Earth to warm by disrupting the biological (fast) carbon cycle, and is therefore increasing the Greenhouse Effect. Although there are large annual fluctuations in carbon dioxide, as it is exchanged back-and-forth between the atmosphere, oceans, soils, and forests, just under half of human emissions (the airborne fraction) remain in the air because the oceans, soils and forests are unable to absorb all of it. As a result, carbon dioxide has been steadily accumulating in the atmosphere.
Figure 1 - Fraction of the total human emissions (fossil fuel burning & land use change) that remain in the: a) atmosphere, b) land vegetation and soil, c) the oceans. From Canadell (2007)
Murry Salby, a professor at Macquarie University in Sydney, Australia, has an upcoming paper that attempts to pin the current rise in carbon dioxide on rising temperatures. Having listened to a podcast of a talk Salby gave at the Sydney Institute earlier this week, he demonstrates a remarkably poor understanding of the carbon cycle, and his hypothesis seems to stem from this fundamental misunderstanding.
Salby's carbon cycle confusion
Professor Salby refers to a number of graphs in his talk, but I have been unable to track down copies of these, therefore we'll have to rely on what I'm able to glean from the podcast, and given it's length, I'll only address some of the more obvious mistakes. At the beginning of the talk Salby states:
"current CO2 values are 380pmmv"(parts per million by volume)
Not an encouraging start that he cites the atmospheric CO2 concentration as it was in 2005, rather than the 393 parts per million by volume (ppmv) it currently is in 2011. Not a fatal flaw of course, but not encouraging either.
"Net annual emission has an average increase of about 1.5ppmv per year. We're on the right planet. That's the annual average increase you just saw. But it varies between years, dramatically by over 100%. From nearly zero in some years to 3ppmv in others. Net global emission of CO2 changes independently of of the human contribution"
At this point the accentuation and drama in Salby's voice make it sound as though he has stumbled onto something momentous, something no one else has noticed before. On the face of it, it seems preposterous that the army of scientists that have worked on carbon cycling over the years could have missed something so glaringly obvious. No, of course they haven't.
As discussed in the first paragraph of this post (and evident in Figure 1), the natural flux of CO2 in and out of natural systems varies from year-to-year. This flux is 20-30 times larger than the annual contribution by humans, but this balances out in the long-term. This variability is driven largely by El Nino and La Nina in the tropical Pacific, which shifts rainfall patterns over much of the world and is associated with warming and cooling of equatorial waters in the Pacific. The change in seawater temperature, and episodic upwelling of carbon-rich deep water, significantly affects the uptake and outgassing of CO2 from the oceans, and of course rainfall variation greatly affects plant growth.
The upshot is that land vegetation takes up more CO2 during La Nina, and expels more CO2 during El Nino. In the ocean, the opposite trend occurs - El Nino leads to more CO2 absorption, and La Nina is when the oceans give up more CO2 (Figure 2).
Figure 2 - (a) time trend in the exchange of CO2 by land-based vegetation (& soil microbes) with the atmosphere. (b) same - but for exchange of CO2 by ocean with atmosphere. Red indicates El Nino and blue La Nina phase. See Keeling (1995).
There is simply no reason why the annual fluctuation should match the human contribution. At least Salby doesn't explain why he expects this to be the case.
Having now convinced himself that short-term net CO2 has nothing to do with the human contribution, Salby therefore deduces long-term net CO2 must also be unrelated to human emissions. He goes on to derive a formula for CO2 rise associated with temperature. Salby claims a good match back to 1960 but therefafter it deviates from actual CO2 measurements by 10ppmv. By 1880, prior to atmospheric CO2 sampling, he estimates atmospheric CO2 at 275ppmv with a whopping uncertainty of 220 to 330ppmv!
In order to explain the deviation between the surface temperature record and his calculated atmospheric CO2 level, Salby blames the surface temperature record as being unreliable. As for his calculated trend disagreeing with the ice core record for the year 1880 (i.e the CO2 in air, from that period, trapped in ice cores) he 'disses' the ice core record claiming it to be only a 'proxy'. Which is news, I'm sure, to respected ice core experts like Dr Richard Alley.
You will note that every time the data disagrees with Salby's 'model', he trusts his 'model' over the data. Which contravenes the 'skeptic lore' that models are worthless and must be bashed, and only data should be trusted.
Q&A time - try not to shoot yourself in the foot!
The question & answer session at the end of Salby's talk throws up a few more comments that just reinforce that he has strayed into a field of science which he just simply doesn't understand. Witness:
"I think it's a pitfall that people look at the ice proxy of CO2 and take it literally. It's not atmospheric CO2, and I don't believe it's CO2 that was even in the atmosphere when that piece of snow was layed down"
This is nonsense. Perhaps Professor Salby should have acquainted himself with glaciology research before making such comments, because CO2 from ancient air trapped in the ice cores is precisely what is measured, albeit with some uncertainty in dating some sections.
"CO2 after the turn of the (21st) century continued to increase, in fact if anything slightly faster, but global temperature didn't. If anything it decreased in the first decade of the 21st century. Now I'm confident the IPCC (Intergovernmental Panel on Climate Change) will come up with an explanation, in fact they've come up with several"
It's here we need to back the truck up a bit. Salby's entire premise is that CO2 in the air directly dependent upon temperature - increase temperature and you increase CO2. Yet here he argues that CO2 can increase without an accompanying increase in temperature. Which contradicts his 'model'. By this time Salby is too focused on 'dissing' the IPCC to notice his own incoherency, and none of the audience picks up on this either.
If the curve fits
Seasoned readers will notice similarities between this Salby claim and a Lon Hocker rebuttal here at SkS last year. But the whole premise seems to follow along the lines of other recent flawed works tendered by Roy Spencer and Craig Loehle & Nicola Scafetta. That is: find some tenuous statistical relationship between two sets of data, and use these to assert the mainstream scientific establishment is wrong. The fact that there is no physical basis for the statistical relationship, or it doesn't fit within the well-established scientific framework, or is contrary to numerous other sets of data, never seems to warrant attention by "skeptic" scientists. It should, because of the implications one can draw.
So what does this work by Salby imply, if it were true? From what I can gather from Salby's podcast, a 0.8°C change in average surface temperature is supposed to lead to about 120ppmv change in CO2. Therefore we can work backward in time to estimate what he reckons atmospheric CO2 would be at the time of the last Ice Age (glacial maximum), a time when global temperatures were about 4-6°C cooler than now . Today atmospheric CO2 is about 393ppm, so with 4°C cooling you already have a negative value for CO2 when we re-trace our steps back to the last ice age. Therefore all plant-based life on Earth must have died (and all the animals that depended on them) according to Professor Salby. And the Earth froze solid too.
Figure 3 - the last Ice Age according to Murry Salby? Fictional image from celestiamotherlode.net
Science - a description of reality, but YMMV
Without viewing Salby's calculations on the temperature/net global CO2 relationship, it's not possible to provide the 'killer blow' to his assertions; however, I don't believe that's necessary, considering the many flaws in Salby's work and fundamental reasoning.
The gradual increase in atmospheric CO2 is less than the total emissions of CO2 from human sources, so by elementary deduction, the excess must be going into the oceans, forests and soils, the other components of the fast carbon cycle.
A tell-tale signature of human fossil fuel emissions is the large fraction of CO2 being driven into the oceans. According to Henry's Law, we would expect the oceans to absorb more CO2 as the air above it becomes increasingly saturated with CO2. In other words the CO2 must be coming from a source external to the fast carbon cycle. This is supported by measurements showing that CO2 is accumulating in the ocean, and is reflected in the declining oceanic pH, showing the ocean is actually gaining CO2 over the long-term, not losing it, as Salby seems to believe.
We also know that the world's land vegetation has increased in mass - through re-growth in forests in the Northern Hemisphere, and CO2 fertilization of tropical forests. So that is gaining carbon too, and the areas affected are so large, we would expect them to have an effect on atmospheric CO2 levels at a global scale.
There are a host of other problems with Salby's 'model', such as the ice core record, and where the warming came from in the first place, but there's no need to go into these details when the fundamental premise of Salby's argument is so clearly wrong.
Intermediate rebuttal written by dana1981
Update July 2015:
Here is a related lecture-video from Denial101x - Making Sense of Climate Science Denial
Last updated on 11 July 2015 by MichaelK. View Archives


Regional Impacts of Climate Change
While rivers west of the Cascades are primarily fed by rainfall,
melting mountain snow sustains rivers east of the mountains during the
dry season, particularly the mighty Columbia Sixty percent of water
flowing through Washington state began as melting snow.
Global warming threatens to eliminate half the Northwest snowpack resource. This “is likely to be the most important of the consequences of global warming to the Northwest,” University of Washington atmospheric scientist Robert Fleagle says.
Warmer temperatures promise to elevate freezing levels. A Pacific Northwest National Laboratory (PNNL) model shows average Cascades snowline rising from its current 3,000 feet to 4,100 feet by 2050-80. The PNNL model shows the volume of water stored in Northwest snowpack shrinking 50 percent by 2050-80. In the scenario some areas near snowline see snowpack drop by up to 90 percent. Many Northwest mountain areas in the 3,000-6,000-foot range become snow-free.
Only 40-60 percent of today’s average March snowpack is projected to remain in most of the Cascades and interior eastside mountains of Oregon and Washington. The westside Oregon Cascades take an even harder hit — Most slopes retain 20 percent or less of current snowpack. The somewhat higher Idaho and Montana Rockies lose 30 percent of snowpack overall.
With less snowpack, and warmer, rainier spring months, mountains are expected to lose their snow cover earlier in the year, making for earlier runoff.
“Streamflow is reduced at the time you need it most, in July, and August,” PNNL climate modeler L. Ruby Leung notes “The earlier melt effectively lengthens the period between the end of snowmelt and the onset of fall rains,” says Alan Hamlet, a University of Washington streamflow expert. “In hydrologic terms this is like making summer several months longer than it is now.”


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The Earth has warmed in the last century and a large component of that warming has been attributed to increased anthropogenic greenhouse gases. There are also numerous processes that introduce strong, regionalized variations to the overall warming trend. However, the ability of a forcing to change the surface air temperature depends on its spatial and temporal distribution. Here we show that the efficacy of a forcing is determined by the effective heat capacity of the atmosphere, which in cold and dry climates is defined by the depth of the planetary boundary layer. This can vary by an order of magnitude on different temporal and spatial scales, and so we get a strongly amplified temperature response in shallow boundary layers. This must be accounted for to assess the efficacy of a climate forcing, and also implies that multiple climate forcings cannot be linearly combined to determine the temperature response.
The detection of processes that affect the surface climate is one of the fundamental tools in our understanding of climate change. The assessment of climate-forcing processes is essentially a statistical, signal-to-noise problem. The most famous example is the detection of warmer surface air temperatures (SATs) attributed to the human-induced enhanced concentration of atmospheric carbon dioxide1,2. One of the challenges in the detection of climate forcing signals has been the strong spatial correlation between the strength of the surface temperature trends and the strength of natural variability3. This relation leads to an inherently low signal-to-noise ratio, regardless of the strength of temperature trends. Indeed, despite the well-established rapid warming in the Arctic4,5,6, the polar regions were the last part of the globe for which there was a successful detection and attribution of the recent warming to anthropogenic-enhanced greenhouse gas (GHG) concentrations7.
In addition to the detection of the influence of enhanced GHGs on surface temperatures, there have been numerous studies assessing how clouds8,9,10,11,12, precipitation8,12,13 and soil moisture8,12 may have introduced some of the observed temporal and regional variations to the overall warming trend that has been seen in the latter half of the twentieth century. In all these studies, the authors have adopted the commonly accepted linear regression model for establishing the relationship between a change in a given property and the temperature response14. However, it has been established from energy-budget models of the climate that temperature changes are linearly related to changes in the surface heating, but also inversely related to the effective heat capacity of the system15,16. Thus, although a linear-model approximation may work well under constrained conditions, such as focusing on a given region or season, in more wide-reaching studies it becomes necessary to account for variations in the effective heat capacity of the atmosphere. In recent times, it has also been recognized that the atmospheric convective mixing may have a strong effect on the observed and simulated climate through modulation of the low cloud and lapse-rate feedbacks17.
As the effective heat capacity is defined by the volume of air through which the heat is mixed, it can be related to the depth of the atmospheric boundary layer18. If we consider the one-dimensional energy budget of the lower atmosphere, then we define the change in SAT as being linearly related to the forcing and feedbacks in the climate system, and inversely related to the effective heat capacity of the system19, such that:
where Q (W m−2) is the heat flux divergence across a boundary layer of depth h (m), ρ (kg m−3) is the air density, cp (J kg−1 K−1) is the heat capacity at constant pressure and θv (K) is the virtual potential temperature that is representative of the boundary layer. Henceforth, θv is taken at a height of 2 m above the ground. If differences in the effective heat capacity of the system are relatively small, we can linearly relate any changes to the heating to a change in θv. However, if there are large variations in the effective heat capacity, we need to account for the dependency of the temperature response on the effective heat capacity. This is especially important when the effective heat capacity is small, as this can strongly magnify the strength of the SAT response to a perturbation in the surface energy budget3.
The hypothesis we put forward here presumes that there is essentially a decoupling of the planetary boundary layer (PBL) from the rest of the atmosphere. Such a decoupling may not be intuitive, but it is a rather natural concept, supported by numerous direct observations20,21, and indeed it is embedded in the PBL schemes of many (if not all) climate models22.
Consider the case of the urban PBL. The urban PBL is better mixed than the PBL in the rural background due to high surface roughness in the urban environment. Nevertheless, even the urban PBL shows a rather clear top boundary, separating it from the rest of the atmosphere23,24, which can be visualized by water vapour (Fig. 1). The well-known urban heat island effect25, which in northern cities may reach up to 10 K (ref. 26), demonstrates how heat may be trapped inside the urban boundary layer.
Now consider in this urban context, which can be so clearly visualized, the presumption that this decoupling is valid on climatological time scales. The urban heat island is highly variable in time and may appear for only a few hours in a given day. However, as the PBL effect is strongly selective and nonlinear, the average over climatological time scales is accumulating. We cannot state that the maximum effect will be observed over the time scale of 30–40 years, as addressed in this study, but over this period of time it is sufficiently large as well. Figure 2 illustrates the urban heat island, that is, the additional anthropogenic heat trapped in by the shallow PBL in Khanty–Mansiysk, according to MODIS satellite data analysis for 2000–2014. Thus, from numerous local studies, it has been firmly established that the PBL depth effect does exist. Our study here is the first to quantify this effect globally, using available data sets and models.
Different climate forcing processes such as variations in solar forcing, GHGs and aerosols have different efficacies in affecting the SAT27,28,29. In this work we have demonstrated that it is the variations in the effective heat capacity of the atmosphere, defined by the PBL depth, which can explain these differences in climate forcing efficacy. We must therefore question the assumption that different climate forcings are linearly additive in nature. This work highlights the pressing need to obtain a robust physical climatology of the boundary layer depth from the observational network and to be able to simulate this climatology with global climate models, to better constrain our estimates of surface climate response to climate forcings.
Temperature trend amplification in shallow boundary layers
Here we have identified the relationship between the boundary layer depth and the trend in θv during the recent warming period, as seen in different re-analyses, and in two state-of-the-art global climate models (Fig. 3). There is a distinctly inverse relationship, where the strongest warming trends are found in shallow boundary layers, and correspondingly low atmospheric heat capacity. The strength of the trends decrease rapidly as we go towards deeper boundary layers and then remain relatively constant across a wide range of boundary layer depths. This amplified temperature trend in the shallowest boundary layers can also be seen in climate models with very different climatologies of the PBL depth. The Norwegian Earth System Model and Geophysical Fluid Dynamic Laboratories Coupled Model 3 have very different climatologies of the PBL depth compared with the re-analyses (Supplementary Fig. 1); both have biases towards deeper PBLs, but they still show a significant correlation between inverse boundary layer depth and the magnitude of trends in θv (R = 0.35, P < 0.05 and R = 0.32, P < 0.05, respectively). This process where heat gets trapped in a shallow layer near the surface by stable stratification in the boundary layer has been shown to be one of the dominant causes of Arctic amplification30,31, but it also has a crucial implication for how we assess the efficacy of different forcings in affecting the SAT. Given the large differences between the climatology of the PBL depth in re-analyses and the global climate models shown here, and the controlling influence the boundary layer depth has on the surface climate32, this is clearly an area that requires more attention, especially in future model development.
Variability in the strength of the boundary layer effect
Owing to its varied climatology (Supplementary Fig. 2), there are some geographical differences as to when the boundary layer depth becomes important in determining the strength of temperature trends. For deep boundary layers the relationship between boundary layer depth and temperature trends is expected to be small, and it is the strength of the local forcing factors themselves, which will principally determine the variations in the rate of warming. However, in shallower boundary layers the strength of temperature trends may be expected to become increasingly dependent on the boundary layer depth. This can be seen in the correlation between the magnitude of temperature trends and the inverse boundary layer depth for different geographical regions (Fig. 4). In high-latitude continental regions such as North America, North Asia and Antarctica, where we frequently get very shallow boundary layers in autumn and winter, there is a strong correlation between inverse boundary layer depth and θv trends. Whereas in more tropical regions such as Africa, South Asia and South America, where cases of shallow boundary layers are less frequent, there is no evidence of this amplification effect.
There is also a strong seasonal variation in the PBL amplification effect: in the boreal spring and summer, the boundary layer is relatively deep and so the amplification effect is relatively weak. However, during the boreal autumn and winter, we can see that the PBL depth is very small over land (Supplementary Fig. 2); thus, during these periods the amplification effect of the PBL depth can become important and should be taken into account. This is why studies that have chosen to focus on the mid-latitudes during the summer seasons have had some success in demonstrating a relationship between a given forcing process and changes to the SAT9, whereas more global analysis of the same processes have shown weaker relationships8. From the ERA-Interim results, we can see that the amplification effect becomes very apparent for boundary layers less than a few hundred metres (Fig. 3). This is quite common, with PBL depths <400 m occurring >46 % of the time in ERA-Interim. This is a good indication of the fraction of time that the PBL depth becomes important in determining the strength of temperature trends.
Including the boundary layer effect in signal detection
One way to account for the PBL depth in the analysis of climate processes is by considering the integrated temperature response within a co-variability framework (Fig. 5). In this framework, the net temperature change is proportional to the time integration of the product of the perturbations in the forcing, dQ, with the inverse boundary layer depth, h−1. In this regard, the conventional methodology is a limit of the co-variability framework, when the variations in the heat capacity can be neglected and we can directly relate perturbations in the forcing to perturbations in the surface temperature (case A, Fig. 5). This is a reasonable approximation only if that forcing is applied solely to deep or weakly varying boundary layers such as the tropical marine boundary layer17. The other limit of the co-variability framework occurs when we have a uniformly applied perturbation to the climate forcing (case B, Fig. 5). In this limit, it is the climatology of the boundary layer depth that principally determines the pattern of warming/cooling in response to a perturbation in the surface heating. The enhanced concentration of GHGs is one such example of a near-uniform perturbation in the surface heating and, as such, there is a strong relationship between the inverse boundary layer depth and the strength of temperature trends in re-analysis (Fig. 3), and both within and between global climate models32.
However, in most cases it is both the PBL depth and the strength of the forcing that will be important in determining the spatial and temporal variations of climate change. In these cases, it is necessary to account for the nonlinear amplification effect of the PBL depth. Let us take the example of the influence of cloud cover on surface temperatures. We expect that an increase in cloud cover during the day will damp incoming solar radiation and thus decrease surface temperatures9. However, an increase in cloud cover at night is expected to reduce longwave cooling and hence result in warmer surface temperatures. Thus, the net effect of changes to the cloud cover on the surface climate is determined by the balance between the cooling effect of damped shortwave radiation and the warming effect of reduced longwave cooling. The cooling effect principally applies during conditions with strong surface heating (when the surface energy balance is dominated by shortwave radiation) and applies to deep PBLs, compared with the warming effect that dominates when there is a net longwave cooling and relatively shallow PBLs. Therefore, when we consider the effect of changes in cloud cover on the atmospheric heat content, rather than on the surface temperature, we expect the cooling effect to become more apparent. This can be seen in the regressions of the cloud cover anomalies, , against surface temperature anomalies, , and against normalized atmospheric heat content anomalies, (Fig. 6). If we look at the sensitivity of surface temperature to cloud cover we can see that in the high latitudes the strong winter-time warming effect of increased cloud cover dominates on the inter-annual scale and we get a strong positive relationship, whereas when we consider the effect of cloud cover on heat anomalies we find a more widespread cooling effect of increased cloud cover, even in these high-latitude continental interiors.This may be expected, as the warming effect of positive cloud cover perturbations on the surface temperature that occurs during the winter months only has a small impact on the atmospheric heat content compared with the cooling that occurs in deep PBLs in the summer months. Thus, when we account for variations in the effective heat capacity, we get a significantly stronger damping of atmospheric heat content from increased cloud cover than we found when assessing surface temperatures: the globally averaged overland temperature sensitivity to cloud cover is −12 (±17) × 10−3 K %−1, compared with a sensitivity of normalized heat content to cloud cover of −32 (± 16) × 10−3 K %−1. This marks a much clearer signal of an overall cooling effect of increased cloud cover on the surface climate.
What is proposed here is essentially a way of accounting for the fact that processes such as changes to cloud cover, soil moisture and so on introduce perturbations to the heating, but what we measure is the temperature perturbation. It has been shown that we can better understand influences on the climate system by considering the heat content, rather than the temperature, of the components of the climate system33; however, the importance of spatial and temporal variations in the heat capacity have largely been neglected. This can be especially important within the diurnal cycle, when the shallow boundary layer depths at night drive strong changes to the nocturnal temperatures12, which have a strong impact on vegetation34.
Here we have shown that by accounting for the variations in the effective heat capacity of the atmosphere we can more accurately assess how a given process influences the surface climate. This allows us to directly compare, in an apples-to-apples manner, the relative importance of different processes in determining the overall response of the climate system to perturbations in the climate forcing. This is also critical for model-model and model-observation comparisons of climate forcing processes. There is a very varied climatology of the PBL in different climate models and re-analysis (Fig. 3) (refs 32, 35, 36) and so these models can exhibit very different temperature responses, given the same change in the climate forcing.
Processing of re-analysis data
We obtained the monthly mean time series of air and dew-point temperature at a height of 2 m above the ground, boundary layer depth and sea-ice concentration from the European Centre for Medium-range Weather Forecasts website for the full period of available data, 1979–2014. The air and dew-point temperature were then used to calculate the virtual potential temperature at a height of 2 m above the ground, θv. The boundary layer depth in the ERA-Interim model is calculated using an iterative bulk-Richardson method, which scans upwards from the lowest model level and interpolates between model levels to find the height at which the bulk Richardson number first exceeds the critical Richardson number, Ricr, taken to be 0.25. Although the bulk-Richardson method has been shown to work well in both stable and unstable stratification35, this definition does create some problems in tropical regions, including parts of South America, Africa and South Asia. The estimation of the boundary layer depth from different methods shows great variation in these regions of high surface humidity and strong convection, and so the ERA-Interim PBL depth is not necessarily reflective of the vertical extent of turbulent mixing36. This is likely to be the reason for the lack of a clear signal of shallow boundary layer amplification of temperature trends in these regions (Fig. 4).
The models used in both re-analysis and GCMs also tend to be biased towards producing deeper-than-observed boundary layers, especially under stably stratified conditions35,37. This is probably due to our limited understanding of geophysical turbulence under stable stratification and the limited applicability of current turbulence parameterization schemes to strongly, stably stratified conditions37. This bias has been shown to lead to an underestimation of the SAT response to climate forcing32.
The sea-ice concentration was used to define the region ‘sea ice’ in Fig. 4. The requirement for being considered over sea ice was that the minimum concentration for a location in a given month be >80% in all years.
The monthly mean time series of air temperature and specific humidity at a height of 2 m above the ground, the boundary layer depth and sea-ice concentration were obtained from the National Center for Atmospheric Research website. The boundary layer depth in this model is calculated in a similar way as to that in ERA-Interim, using the bulk-Richardson formulation and the same critical Richardson number.
Analysis of climate model data
To calculate the boundary layer depth in these models, we used a bulk Richardson method. This was chosen due to the limits of data availability for other methods, for example, no information on local gradients was available, which would be required for a flux-Richardson method, and the vertical resolution in these models is too coarse for any of the profile-based methods. The bulk-Richardson method has also been shown to be the most robust across a wide range of thermal stability and is consistent with the method used in the re-analyses.
First, we obtained the 6-hourly resolution three-dimensional fields of the wind components, humidity and temperature, and the 3-hourly resolution surface temperature, pressure and humidity for the period 1979–2005 for Norwegian Earth System Model and Geophysical Fluid Dynamic Laboratories Coupled Model 3 from the British Atmospheric Data Centre archive. The temperature and humidity fields were used to calculate the virtual potential temperature at each model level and at the surface using the definition , where θ is the potential temperature and M is the water–vapour mixing ratio. The thickness of each model level, Z, was calculated using a hydrostatic assumption, such that , where i is the index of the model level with the surface being i = 0, θv is the virtual potential temperature, p the pressure, Rd the dry gas constant ( 287.06 J kg−1 K−1) and g the surface gravity ( 9.807 m s−2). The geometric height of each level was then calculated by the summation of the thickness of the lower levels. The bulk Richardson number at each pressure level was calculated using the difference between that level and the surface: , where g is the surface gravity, z is the height above the surface, θv is the virtual potential temperature at height z, θvs is the virtual potential temperature at a height of 2 m above the surface and U is the wind speed at height z. We then scanned upwards from the lowest level above the surface and linearly interpolated between levels, to find the first height at which the bulk Richardson number exceeded the critical value, Ricr. We also applied a requirement that the PBL depth should be >10 m and <4 km: as this was an automated method, these constraints were necessary to avoid cases where the routine returned unphysical PBL depths.
The correlations given in Fig. 4 are the area-weighted spatial correlations between the monthly mean inverse boundary layer depth and the inter-annual trend in the monthly mean virtual potential temperature at a height of 2 m above the ground. The P-values were computed to test against the null hypothesis of zero correlation using a Student’s t distribution for a transformation of the correlation.
The regression coefficients in Fig. 6 were determined from a least-square, best-fit linear regression between the two variables under consideration. These were the cloud-cover anomalies against the anomalies in θv and the cloud cover anomalies against the normalized heat anomalies, , where is the area-weighted, climatological mean boundary layer depth. Anomalies were calculated by removing the climatological mean of each month from the time series using the full period of the data, 1979–2014.
The Matlab code used to generate the PBL depth and virtual potential temperature data sets discussed in this work have been archived by the authors and are available on request from the corresponding author, R.D. firstname.lastname@example.org).
All the model data used in this study is publicly available from the respective host institutions or archives. The ERA-Interim reanalysis data may be obtained from http://dx.doi.org/10.5065/D6CR5RD9. The CFSR reanalysis data are available from http://dx.doi.org/10.5065/D69K487J and the climate model data are available from https://esgf-data.dkrz.de/search/cmip5-dkrz/.
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Support for this study was provided by the Belmont Forum project Anthropogenic Heat Islands in the Arctic—Windows to the Future of the Regional Climates, Ecosystems and Society and by the Bjerknes Centre for Climate Research project, BASIC. We thank T. Wolf and V. Miles for supporting materials. We also thank the Environmental Modeling Center (EMC), National Centers for Environmental Prediction (NCEP) for providing the CFSR data, the European Centre for Medium Range Weather Forecasting for the ERA-Interim, the NorESM and GFDL modelling groups for producing model data and the Earth System Grid Foundation for archiving that data.
The authors declare no competing financial interests.
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Cite this article
Davy, R., Esau, I. Differences in the efficacy of climate forcings explained by variations in atmospheric boundary layer depth. Nat Commun 7, 11690 (2016). https://doi.org/10.1038/ncomms11690
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Very warm and humid with clouds and sun; breezy this afternoon with a shower or thunderstorm around
Mostly cloudy, warm and humid with a couple of showers and a thunderstorm
Rises at 6:20 AM with 14:36 of sunlight, then sets at 8:56 PM
Rises at 4:02 PM with 11:46 of moolight, then sets at 3:48 AM
May 20, 2013; 12:57 PM ET After last night's severe weather outbreak, conditions became more tranquil in the Plains and Midwest; however, we have just received the first severe weather report of the last few hours.


I am going to start a series of the Cloud of the Week. This series contains some information from my book The Message of the Clouds and it will cover the most useful clouds for weather forecasting.
Pannus clouds are probably my favourite cloud, not because they ar e particularly attractive but because they are extremely accurate weather forecasters. Pannus clouds are grey fragmented or wispy clouds which form below the main cloud base of precipitating clouds (clouds producing rain or snow). They form as precipitation from above moistens the air until it is so damp that these dark clouds form. They can be known as virga or fallstreaks when they are in a wispy form like the photo below.
Pannus clouds are often fragmented due to turbulent winds and they appear to rapidly move and change shape. They indicate that the clouds above are already raining and that there will be rain on the ground in the next ten minutes. These clouds increase in numbers as the rain falls until they cover the whole sky. Pannus clouds form below cumulonimbus clouds and nimbostratus clouds, although they mainly form below the latter.
Pannus clouds are useful because they almost always indicate rain in the next few minutes so if you see these clouds remember to wear the waterproofs and pack up the picnic!
I hope you enjoyed the first cloud of the week and come back next week for more! If you would like more information on weather forecasting using this cloud and with many other clouds you might find my book The Message of the Clouds helpful. It contains all the information you need to forecast the weather yourself just by glancing up at the clouds as well as detail on how the local terrain can affect the weather. Find out more about The Message of the Clouds here.


Isis made two landfalls in Mexico, one in southern Baja California as a
tropical storm, and another near Los Mochis as a category one
hurricane on theSaffir/Simpson Hurricane Scale.
a. Synoptic History
A tropical wave, which on 19 August produced the tropical depression
that became Atlantic Hurricane Bonnie, moved westward across the Caribbean Sea from 21-24 August
and crossed Central America on 25 August. As the wave moved into an area covered by a large lower-tropospheric
cyclonic circulation (or, at least, cyclonic turning) covering southern Mexico and the adjacent waters, its
forward speed slowed. A broad area of disturbed weather, associated with these atmospheric features,
persisted over the tropical eastern north Pacific between 90W-110W from 26-29 August. A more
localized area of low-level cyclonic rotation became evident on 29 August a little over 500 n mi
south-southeast of Cabo San Lucas. There was little change in organization for the next day or two. On 31
August, the system was characterized by two main areas of dense cloudiness located a few degrees
northeast and southwest of the center of circulation. By 0000 UTC 1 September, even though deep
convection was still not well-organized, the low-cloud circulation was sufficiently well-defined so that
the system could be designated as a tropical depression, centered slightly less than 300 n mi south of
Cabo San Lucas (Table 1). The overall track of this
tropical cyclone is displayed in
Figure 1 (16K GIF).
As the cyclone moved slowly northward to north-northwestward, it gradually
intensified. Ship observations indicate that the cyclone strengthened into Tropical Storm Isis by 1800
UTC 1 September, located about 170 n mi south of Cabo San Lucas. With a 500 mb trough, extending
south-southwestward from the California/Arizona border, providing a southerly steering flow, Isis
moved northward at about 10 knots. Its center made a first landfall,
over extreme southeastern Baja California, at 1200 UTC 2 September. Isis then moved slightly east of north,
over the Gulf of California while strengthening to a 65-knot hurricane,
an eye becoming apparent
on visible satellite imagery. The hurricane more or less maintained this strength until the center made its
final landfall in Mexico at Topolobampo, close to Los Mochis, around 0300 UTC 3 September. Isis
weakened to a tropical storm a few hours after landfall, and to a depression by 1800 UTC 3 September.
The system dissipated over the mountains of Mexico soon thereafter.
b. Meteorological Statistics
Figures 2 (11K GIF) and 3
(11K GIF) depict the curves of minimum central sea-level
pressure and maximum one-minute average "surface" (10 meters above ground level) wind speed,
respectively, as a function of time. Also plotted are the observations on which the curves are based,
consisting of Dvorak-technique estimates (from TAFB, the
Synoptic Analysis Branch, SAB, and the U.S.
Air Force Global Weather Agency,
AFGWC in the figures) using satellite imagery.
Islas Marias reported south-southwesterly winds at a ten-minute average speed of
40 knots at 0000 UTC 2 September. San Jose del Cabo reported
270/20 knots (ten-minute average) with gusts to 40 knots at 1445 UTC
The following 24-hour rainfall totals were reported: 12.99 inches at Los Cabos, Baja
California Sur; 8.86 inches in Sinaloa; and 4.72 inches in Sonora.
Table 2 lists ship reports of 34-knot or greater winds associated with Isis.
c. Casualty and Damage Statistics
According to information provided by the government of Mexico to the
World Meteorological Organization,
Isis caused 14 deaths in Mexico, and destroyed 769 houses.
d. Forecast and Warning Critique
Mean official track forecast errors for Isis at 12, 24, and 36 hours were 36, 79, and 87 n
mi, respectively. Although these errors are low, there were too few cases six, four and two respectively)
for them to be considered statistically meaningful. In any case, the cyclone moved fairly close to the
track predicted in the NHC advisories.
The average official absolute wind speed forecast errors were also rather low;
nonetheless, the slight strengthening of Isis to a hurricane was not forecast.
Table 3 lists the watches and warnings that the government of Mexico issued for their
country. The center of Isis reached Baja California 15 hours after the issuance of a tropical storm
warning. There was only about six hours between the time of issuance of a hurricane warning on the
coast of mainland Mexico and the time of arrival of the center.
Table 3. Watch and warning summary, Hurricane Isis, September, 1998.
|1/2100||tropical storm warning issued
||Baja California south of a Dolores to Puerto Cortez line|
|2/0300||tropical storm warning extended
||Baja California south of a line from Santa Rosalia to Punta Abreojos|
|tropical storm warning issued||coast of Mexico from El Dorado to Guaymas|
|2/2100||hurricane warning issued
||coast of Mexico from El Dorado to Bahia Kino and east coast of Baja California from Dolores to Punta San Gabriel|
|tropical storm warning shifted northward
||west coast of Baja California from Puerto Cortez to Punta Eugenia |
|3/0900||all warnings discontinued
|hurricane warning replaced by tropical storm warning
||coast of Mexico from Los Mochis to Guaymas|
|3/1800||tropical storm warning discontinued
||coast of Mexico from Los Mochis to Guaymas|


Steady snow will taper off and end around 4pm. Mostly cloudy and windy. Temperatures steady near the upper teens. Winds WSW at 15 to 20 mph. Chance of snow 70%. Additional snowfall about half an inch through 9:30pm. Hourly Details
Intermittent snow showers, especially early. Low 17F. Winds WSW at 10 to 20 mph. Chance of snow 50%.
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« View county listSpecial Weather Statement
Including the cities of Wallace, Warsaw, Kenansville, Beulaville,
Faison, Maysville, Pollocksville, Trenton, Morehead City,
Beaufort, Newport, Atlantic Beach, Emerald Isle, Jacksonville,
Richlands, Swansboro, and North Topsail Beach
436 AM EST Fri Feb 23 2018
...AREAS OF DENSE FOG ARE OCCURING ACROSS PORTIONS OF EASTERN
NORTH CAROLINA EARLY THIS MORNING...
Areas of dense fog with visibilities of one half to one quarter
of a mile are occurring across southern portions of Eastern North
Carolina early this morning. This fog is expected to adversely
affect the morning commute to work and school.
Motorists are urged to slow down when traveling in areas with
reduced visibilities. Use only low beam headlights and leave extra
time to reach your destination.
The fog is forecast to dissipate between 8 and 9 AM.


Southeastern Grand Banks: Synopsis
Technical Marine SynopsisIssued 10:00 AM NDT 23 August 2014 Today Tonight and Sunday At 10:00 a.m. NDT today departing low 992 mb located east of Funk
At 10:00 a.m. NDT today ridge located on a line northeast-southwest
By 10:00 a.m. NDT Sunday ridge located on a line northeast-southwest
over western Newfoundland.
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