Thursday, August 4, 2011

August 5: Emily Fizzles, Dallas Cooks (updated heat records, severe storm reports for 2011)


"Ike": the last hurricane to make landfall in the USA in 2008. Last year saw above-average hurricane activity in the Atlantic and Carribean, but none of the hurricanes hit the United States.


"...The atmosphere and Atlantic Ocean are primed for high hurricane activity during August through October,” said Gerry Bell, Ph.D., lead seasonal hurricane forecaster at the Climate Prediction Center.  “Storms through October will form more frequently and become more intense than we’ve seen so far this season." - Dr. Gerry Bell, lead seasonal hurricane forecaster at the Climate Prediction Center in a NOAA story below.

108 F. high temperature in Dallas/Ft. Worth Thursday (new record high). Yesterday was the 34th day/row above 100 at DFW. All-time record is 42 days/row, set in 1980. 100+ heat is likely in Dallas for another 7-10 days.

“...The Missouri River is flooding,” said Dr. James Hansen, Director of NASA’s Goddard Institute for Space Studies, during a visit to Omaha on Tuesday. “We’ve had 100 years floods now a couple of times on the Missouri River recently. That’s one of the expected consequences of increasing atmospheric carbon dioxide.” - story from KVNO News on the Missouri River flooding below.


An Unusually Severe Summer For The Twin Cities of Minnesota. Check out this eye-opening post from the Chanhassen office of the NWS:

"Meteorologists at the NWS Storm Prediction Center (SPC) issue national convective outlooks that extend out to a week for severe thunderstorm potential.  An outlook for day 1, or today or tonight, is issued and updated a handful of routine times as the day unfolds.  From June 30th through August 2nd, a span of 34 days, the NWS Chanhassen CWA was under at least a slight risk for 23 of them (68%).  From July 14th through August 2nd, a slight risk or higher severe threat was in effect 16 of those days, an astounding 80%.  More insight on the SPC risks and what they mean can further be read about here. "




"Emily": RIP? Tropical Storm Emily weakened into a tropical wave Thursday afternoon, the main circulation dissipating over Hispaniola, dumping out some 10"+ rains on Haiti and the Dominican Republic. There's still a small chance that Emily will redevelop over the Bahamas - but the threat posted to the east coast of Florida has diminished. Even so, hurricane forecasters will be keeping a close eye on the soggy remains of Emily, watching for signs of strengthening over the warm waters of the Caribbean. Satellite loop courtesy of WSI's Intellicast. From NHC:

SINCE ITS INCEPTION...EMILY NEVER HAD A PARTICULARLY ROBUST
LOW-LEVEL CIRCULATION...AND THE HIGH TERRAIN OF HISPANIOLA
CONTRIBUTED SIGNIFICANTLY TO THE FURTHER DEGENERATION OF THE
CYCLONE TODAY. SATELLITE...RECONNAISSANCE AIRCRAFT AND SURFACE
OBSERVATIONS INDICATE THAT EMILY NO LONGER HAS A CLOSED
CIRCULATION....AND THE SYSTEM HAS BEEN DOWNGRADED TO A TROUGH OF
LOW PRESSURE WITH ITS AXIS ALONG 75W. THIS WAS A BIG WIN FOR THE
ECMWF GLOBAL MODEL...WHICH NEVER DEVELOPED EMILY AND ALWAYS
FORECAST DISSIPATION NEAR HISPANIOLA. 

THERE IS STILL A LARGE AREA OF ORGANIZED DISTURBED WEATHER OVER
HISPANIOLA ASSOCIATED WITH THE REMNANTS OF EMILY. THIS ACTIVITY IS
EXPECTED TO SPREAD TOWARD THE WEST-NORTHWEST AND NORTHWEST OVER
EASTERN CUBA AND THE SOUTHEASTERN BAHAMAS WITH SOME POTENTIAL
FOR REGENERATION IN THE NEXT DAY OR TWO.  

EVEN THOUGH EMILY HAS DISSIPATED...HEAVY RAINS REMAIN A THREAT FOR
THE DOMINICAN REPUBLIC AND HAITI.



Friday Severe Threat. Storms may exceed severe limits from eastern Montana and Wyoming into the Dakotas and far western Minnesota - another (slight) severe risk over the southeastern USA, from Memphis and Huntsville to Atlanta and Charlotte, firing up along a stalled frontal boundary. Data courtesy of SPC.



ERCOT: "High Probability" Of Rolling Blackouts. The risk of brown-outs and even black-outs related to extreme heat in Texas is on the increase. Here's an update from Austin's KUT.com: "The state's energy regulator said in a Tweet moments ago that there is now a "high probability" of rolling blackouts across the state. The Electric Reliability Council of Texas escalated the Energy Emergency Alert to Level 2B, meaning energy reserves are below 1,750 megawatts and continuing to decline. If power reserves continue to become depleted, ERCOT will initiate a Level 3 emergency. This is the worst case scenario involving rolling blackouts across the state. Everyone can expect outages that are supposed to range from 15 to 45 minutes in length, although they may be longer.  Hospitals and other essential services are not supposed to lose power."


Heat Wave/Drought Highlights:  Tropical Storm Don—which made landfall on July 29 between Brownsville and Corpus Christi—was a mighty disappointment for parched Texas.  Scattered showers, totaling mostly less than an inch, were limited to Deep South Texas, as the storm literally disintegrated upon moving inland.  Meanwhile, a record-shattering string of 100-degree readings continued into August across parts of the Lone Star State.  Tyler, TX, posted a 36-day streak (and counting) of triple-digit heat from June 28 – August 2, nearly doubling its former mark of 20 days set from July 15 – August 3, 1998.  Dallas-Ft. Worth registered highs of 100°F or higher on 32 consecutive days (and counting) from July 2 – August 2, second only to a 42-day stretch of triple-digit heat from June 23 – August 3, 1980.  With an average temperature of 89.2°F, July 2011 was the hottest month on record in Oklahoma City, Oklahoma, smashing its Dust Bowl-era record of 88.7°F set in August 1936.  Childress, Texas (90.2°F), also demolished its long-standing “hottest month” record, previously set with 89.0°F in July 1934.  Elsewhere in Texas, Wichita Falls (92.9°F) edged its July 1980 standard of 91.9°F.  For the second consecutive month, Lubbock, TX, experienced its hottest month on record (85.9°F in June and 86.0°F in July; previously, 85.4°F in July 1966).  Adding insult to injury was the ongoing historic drought.  For example, Midland, Texas, completed another month without measurable precipitation (rainfall greater than a trace last fell on May 20).  Midland also endured its driest 10-month period on record, with just 0.18 inch falling from October 2010 - July 2011.  The previous record-low precipitation for any 10-month period in Midland was 2.60 inches from October 1950 - July 1951.
The coverage of Texas rangeland and pastures in very poor to poor conditions stood at 93% on July 31, according to USDA.  The rangeland and pasture situation was nearly as bad in Oklahoma (86% very poor to poor), Arkansas (79%), and Kansas (57%).  Oklahoma’s row crops were in particularly bad shape, with USDA rating 88% of the cotton and 74% of the sorghum in very poor to poor condition.  By month’s end, topsoil moisture was reported to be 100% very short to short in Oklahoma, 97% in Texas, 89% in Arkansas, and 73% in Kansas.
* data above courtesy of Chad Merrill from Earth Networks.


Record-Setting Dew Points In South Dakota. Aberdeen, South Dakota reported a dew point of 82 F on August 1, a new all-time record. Data courtesy of NOAA and Chad Merrill at Earth Networks.



More Record Highs For Thursday. Thanks to NOAA and Chad Merrill from Earth Networks:

...RECORD MAXIMUM TEMPERATURE SET AT OKLAHOMA CITY...
THE MAXIMUM TEMPERATURE TODAY AT WILL ROGERS WORLD AIRPORT REACHED
108 DEGREES. THE BREAKS THE RECORD HIGH OF 106 DEGREES, LAST REACHED
IN 2008.
TEMPERATURE RECORDS FOR OKLAHOMA CITY DATE BACK TO 1891.
* photo above courtesy of the U.K. Guardian newspaper.
...RECORD MAXIMUM TEMPERATURE BROKEN AT WICHITA FALLS...
THE MAXIMUM TEMPERATURE AT SHEPPARD AIR FORCE BASE IN WICHITA FALLS
TODAY WAS 111 DEGREES. THIS BREAKS THE RECORD FOR AUGUST 4TH. THE
PREVIOUS RECORD OF 109 DEGREES WAS LAST REACHED IN 2008.
TEMPERATURE RECORDS FOR WICHITA FALLS DATE BACK TO 1923.
 
...RECORD HIGH TEMPERATURE SET AT MCALESTER OKLAHOMA...
A RECORD HIGH TEMPERATURE OF 107 DEGREES WAS SET AT MCALESTER
OKLAHOMA TODAY. THIS BREAKS THE PREVIOUS RECORD OF 106...SET IN 1956.
 

...ADDITIONAL ALL TIME RECORDS ESTABLISHED ACROSS NORTHWEST ARKANSAS...
SEVERAL NATIONAL WEATHER SERVICE COOPERATIVE NETWORK OBSERVING
SITES ACROSS NORTHWEST ARKANSAS ESTABLISHED NEW ALL TIME HIGH
TEMPERATURES YESTERDAY...AUGUST 3RD.
 
AT OZARK...THE HIGH TEMPERATURE REACHED 114 DEGREES. THE PREVIOUS
ALL TIME RECORD WAS 108 DEGREES...SET ON AUGUST 2ND 2011.
 
AT GRAVETTE...THE ALL TIME HIGH TEMPERATURE OF 114 DEGREES WAS
TIED YESTERDAY. THE PREVIOUS RECORD WAS ESTABLISHED ON JULY 19TH 1936.
DATA RECORDS FOR GRAVETTE BEGAN IN 1898.
 
IT SHOULD BE NOTED...THE DATA FOR THE PRESENT OBSERVATION SITE IN OZARK
BEGINS IN 1994. THE ORIGINAL OBSERVING LOCATION IN OZARK WAS
CLOSED IN FEBRUARY 1994...AND MOVED TO THE PRESENT LOCATION. THE
ORIGINAL SITE BEGAN COLLECTING DATA IN 1893. WHILE SOME DATA IS
AVAILABLE FOR THE ORIGINAL OZARK SITE...THERE ARE SEVERAL YEARS OF
MISSING DATA. HOWEVER...CONSIDERING THE DATA AVAILABLE...A RECORD
TEMPERATURE OF 116 DEGREES WAS ESTABLISHED AT THE ORIGINAL SITE ON
JULY 31ST AND AUGUST 1ST 1986.
 
...RECORD DAILY HIGH TEMPERATURE SET AT WACO...
THE HIGH TEMPERATURE TODAY...AUGUST 4TH...AT WACO REGIONAL AIRPORT
WAS 108 DEGREES. THIS BREAKS THE PREVIOUS RECORD HIGH FOR THIS DATE
OF 106 DEGREES SET IN 1951.


...ALL-TIME RECORD WARMEST MINIMUM TIED AT DALLAS/FORT WORTH...
...DAILY RECORD HIGH TEMPERATURE SET AT DALLAS/FORT WORTH...
 
ON THURSDAY AUGUST 4TH...DALLAS/FORT WORTH INTERNATIONAL AIRPORT
RECORDED A HIGH TEMPERATURE OF 108 DEGREES AND A LOW TEMPERATURE OF
86 DEGREES. THE HIGH TEMPERATURE OF 108 BREAKS THE OLD RECORD OF 107 SET IN
1951. THE LOW TEMPERATURE OF 86 TIES THE ALL-TIME WARMEST MINIMUM
TEMPERATURE EVER RECORDED AT DALLAS/FORT WORTH.
 
* photo above courtesy of world66.com.
 
...RECORD HIGH TEMPERATURE TIED AT CORPUS CHRISTI...
A RECORD HIGH TEMPERATURE OF 100 DEGREES WAS TIED AT CORPUS CHRISTI TODAY.
THIS TIES THE OLD RECORD OF 100 SET IN 1990.
 
...RECORD HIGH TEMPERATURE SET AT DEL RIO ...
A RECORD HIGH TEMPERATURE OF 104 DEGREES WAS SET AT DEL RIO  TODAY.
THIS TIES THE OLD RECORD OF 104 SET IN 1998.
 
...RECORD HIGH TEMPERATURE SET AT AUSTIN CAMP MABRY...
A RECORD HIGH TEMPERATURE OF 107 DEGREES WAS SET AT AUSTIN CAMP MABRY TODAY.
THIS BREAKS THE OLD RECORD OF 105 SET IN 1951.
 
...RECORD HIGH TEMPERATURE SET AT SAN ANTONIO...
A RECORD HIGH TEMPERATURE OF 103 DEGREES WAS SET AT SAN ANTONIO TODAY.
THIS TIES THE OLD RECORD OF 103 SET IN 1962.
 


1,676 Tornadoes As Of July 31. This is a preliminary count from SPC - state by state details can be found here.


14,588 Reports Of Damaging Winds As Of July 31. The coverage of severe straight-line wind reports east of the Rockies is pretty amazing, again, courtesy of SPC, the Storm Prediction Center. Winds over 58 mph are plotted.


8,017 Reports Of Damaging Hail As Of July 31. Damaging hail is defined as 1" diameter or larger. Map courtesy of SPC.

Is Daytona Beach Ready To Handle Possible Flooding From Tropical Storm Emily? Central Florida News 13 takes a look at the Daytona Beach area, in light of a recent (significant) flood in 2009 The city of Daytona Beach has spent the last two years working to improve its storm drainage system after severe flooding in 2009. Is it ready now for what a tropical storm might bring this weekend? One of the hardest hit areas two years ago was a retention pond that flooded out residents near North Street and Mark Avenue. Now, neighbors are taking no chances. City workers have pumped as much water as they could out of the retention pond to make sure water levels are low enough to handle heavy rain Emily may dump on Daytona Beach. During 2009's heavy storms, nearly 25 inches of rain fell on the area in just three days. Homes and streets were overwhelmed by water, causing serious damage. Since then, the city has taken on a number of projects to improve the storm drainage system. Nearly half a dozen of those projects have already been completed, but city officials said they are still working to get the millions more in funding needed for a number of other areas that could cause problems."


NOAA's Atlantic Hurricane Season Update Calls For Increase In Named Storms. We got lucky last year (no direct strikes from any hurricanes - they all stayed out at seas). The USA may not be quite as lucky this year, according to NOAA: “The atmosphere and Atlantic Ocean are primed for high hurricane activity during August through October,” said Gerry Bell, Ph.D., lead seasonal hurricane forecaster at the Climate Prediction Center.  “Storms through October will form more frequently and become more intense than we’ve seen so far this season.” A few highlights of the NOAA report:
  • NOAA issued its updated 2011 Atlantic hurricane season outlook Thursday raising the number of expected named storms from its pre-season outlook issued in May.
  • Forecasters also increased their confidence that 2011 will be an active Atlantic hurricane season.        
  • Key climate factors predicted in May continue to support an active season. These include: the tropical multi-decadal signal, which since 1995 has brought favorable ocean and atmospheric conditions, leading to more active seasons; exceptionally warm Atlantic Ocean temperatures (the third warmest on record); and the possible redevelopment of La Niña.  Reduced vertical wind shear and lower air pressure across the tropical Atlantic also favor an active season.
  • Based on these conditions and on climate model forecasts, the confidence for an above-normal season has increased from 65 percent in May to 85 percent. Also, the expected number of named storms has increased from 12-18 in May to 14-19, and the expected number of hurricanes has increased from 6-10 in May to 7-10.
  • These ranges are indicative of an active season, and extend well above the long-term seasonal averages of 11 named storms, six hurricanes and two major hurricanes.
  • The Atlantic basin has already produced five tropical storms this season: Arlene, Bret, Cindy, Don and Emily. All eyes this week are on Emily, which continues to develop and move towards the United States.
  • The last hurricane to make landfall in the United States was Ike in 2008. Last year saw above-normal hurricane activity, but none made landfall in the United States.
  • August through October are peak months of the Atlantic hurricane season, and FEMA urges people not to be lured into a false sense of security by the lack of hurricanes so far this year.
* photo above is Hurricane Danielle in 2010, taken from the Space Shuttle, courtesy of NASA.


Weather Tech Keeps A Step Ahead Of Storms. The story from TVNewsCheck. Here's an excerpt: "Weather system vendors are creating new tools designed to bring new elements into weather presentations, including real-time observation data and viewer videos of storm damage, as well as hooks into social media and mobile apps that let stations deliver weather information to viewers regardless of what screen they're viewing. This is the fifth in a series of articles appearing this week that collectively constitute a TVNewsCheck Special Report on Severe Weather News. The other stories in the series are below. A rash of severe weather this spring, including deadly tornadoes in Alabama in April and Missouri in May, has cast a brighter spotlight on stations’ crucial role in warning their viewers of dangerous weather and providing extended, sometimes round-the-clock, coverage in the aftermath of a storm. And vendors of weather systems are stepping up with new tools designed to bring new elements into weather presentations, including real-time observation data and viewer videos of storm damage, as well as hooks into social media and mobile apps that allow stations to deliver weather information to viewers regardless of what screen they are viewing."

* We use cutting-edge weather technology at WeatherNation from a number of vendors: Baron Services ("OMNI" graphic above), Weather Central and a Berlin company, The Meteo Group. In addition we create our own, in-house graphics and maps via Ham Weather.

Earth May Have Once Had Two Moons. The BBC has the full story: "A new theory suggests the Earth once had a small second moon that perished in a slow motion collision with its "big sister". Researchers suggest the collision may explain the mysterious mountains on the far side of our Moon. The scientists say the relatively slow speed of the crash was crucial in adding material to the rarely-seen lunar hemisphere. Details have been published in the journal Nature. The researchers involved hope that data from two US space agency (Nasa) lunar missions will substantiate or challenge their theory within the next year. For decades, scientists have been trying to understand why the near side of the Moon - the one visible from Earth - is flat and cratered while the rarely-seen far side is heavily cratered and has mountain ranges higher than 3,000m."

Getting Bin Laden. If you haven't read the New Yorker story you're missing a remarkable bit of journalism and story-telling about what really happened that night in Abbottabad, Pakistan. Here's a brief excerpt: "Shortly after eleven o’clock on the night of May 1st, two MH-60 Black Hawk helicopters lifted off from Jalalabad Air Field, in eastern Afghanistan, and embarked on a covert mission into Pakistan to kill Osama bin Laden. Inside the aircraft were twenty-three Navy SEALs from Team Six, which is officially known as the Naval Special Warfare Development Group, or DEVGRU. A Pakistani-American translator, whom I will call Ahmed, and a dog named Cairo—a Belgian Malinois—were also aboard. It was a moonless evening, and the helicopters’ pilots, wearing night-vision goggles, flew without lights over mountains that straddle the border with Pakistan. Radio communications were kept to a minimum, and an eerie calm settled inside the aircraft."
Apple To Launch iPhone 5 In September. The latest from All Things Digital and yourversion.com: "So those rumors claiming the iPhone 5 will debut in late September? They’re wrong. Instead, it’s going to be an October surprise — the month in which Apple plans to launch its next-gen iPhone. Sources with knowledge of the situation say reports claiming AT&T has blacked out employee vacations during the last two weeks of September in preparation for the retail debut of the next iPhone are misinformed. “I don’t know why AT&T’s calling for all hands on deck those weeks, but it’s not for an iPhone launch,” a source familiar with Apple’s plans said. So when can we expect the company to uncrate the iPhone 5? “October,” the source said, while declining to offer a hard-launch date. Other sources said it will be later in the month, rather than earlier. The source offered no details on the device’s design, but supply-chain chatter has previously indicated that the iPhone 5 will use the faster A5 processor on which the iPad 2 runs, a Qualcomm dual mode GSM/CDMA baseband, and a higher resolution eight-megapixel rear camera.




 
Climate Stories....


Pawlenty: "Most Global Warming Is Natural". Here's a story from The Hill: "GOP White House hopeful Tim Pawlenty said this week that most or all climate change stems from natural causes. The statement puts the former Minnesota governor at odds with GOP front-runner Mitt Romney, who believes climate change is occurring and that humans have contributed. It also could help Pawlenty, who has struggled to raise his standing in polls of GOP voters, stand out to conservatives at the Iowa caucuses and other early GOP presidential contests next year. Pawlenty spoke about climate change in a wide-ranging interview with The Miami Herald. Asked whether there is man-made climate change, Pawlenty replied, “there’s definitely climate change,” then said: “The more interesting question is how much is a result of natural causes and how much, if any, is attributable to human behavior. And that’s what the scientific dispute is about.”(photo credit: politico.com).


Global Warming Expert: (Missouri) Flooding Caused By Climate Change. KVNO News has the story: "Overlooking the swollen banks of the Missouri river at Omaha’s riverfront landing, one scientist has an important explanation for the past three months of flooding. While many consider the flood man-made, a result of water releases by the U.S. Army Corps of Engineers upriver, this theory aims to look deeper into the root of the problem. “The Missouri River is flooding,” said Dr. James Hansen, Director of NASA’s Goddard Institute for Space Studies, during a visit to Omaha on Tuesday. “We’ve had 100 years floods now a couple of times on the Missouri River recently. That’s one of the expected consequences of increasing atmospheric carbon dioxide.” Hansen, who is considered by many to be one of the world’s leading experts on global warming, said the Missouri river is a prime example of how global warming is affecting the earth. “This is a problem which is not easy for the person in the street to see,” he said. “Unless you do statistics, and you see that the frequency of these events is changing. It’s not so easy to see that changes are occurring because the climate system has tremendous inertia.” Hansen explained, “The ocean is four kilometers deep, the ice sheets are two or three kilometers thick, so they don’t respond immediately as we begin to change the atmospheric composition. What that means is that we’ve only experienced about half of the warming that will be cause by the gases already in the atmosphere.”

Where Will Climate Change Affect Health The Most? KQED-TV takes a look at the latest NRDC report: "The Natural Resources Defense Council (NRDC) released an interactive tool today that maps climate-related health risks across the country, including extreme heat, poor air quality, drought, flooding, and infectious diseases. The maps present a snapshot of current health vulnerabilities using recent data at the state and county levels. “If we stay on our present course, we can expect these health vulnerabilities from climate change to accelerate” said NRDC Senior Scientist Kim Knowlton on a conference call with reporters. “We need to prepare for the worst in extreme events and the health vulnerabilities that will result.” According to the NRDC, one of the main health impacts Californians are facing with climate change is air pollution.  A recent report from the Public Policy Institute of California finds that two-thirds of Californians already see air pollution as a big problem.  The NRDC tool asserts that 90% of Californians live in areas that violate air quality standards, and that climate change will worsen this by bringing smoggier and hotter days.

Top 10 Surprising Results Of Global Warming. #10: Forest Fire Frenzy. Here's a series of posts from Live Science focusing on some of the more unusual & unexpected implications of a slowly warming atmosphere: "While it's melting glaciers and creating more intense hurricanes, global warming also seems to be heating up forest fires in the United States. In western states over the past few decades, more wildfires have blazed across the countryside, burning more area for longer periods of time. Scientists have correlated the rampant blazes with warmer temperatures and earlier snowmelt. When spring arrives early and triggers an earlier snow-melt, forest areas become drier and stay so for longer, increasing the chance that they might ignite." (Photo Credit: USGS.gov - Photograph by J.D. Griggs on April 22, 1990).


Poll: Majority Thinks Global Warming "Scientists" Lie. Really? Fox "News" has the "story": "The debate over global warming has intensified in recent weeks after a new NASA study was interpreted by skeptics to reveal that global warming is not man-made. While a majority of Americans nationwide continue to acknowledge significant disagreement about global warming in the scientific community, most go even further to say some scientists falsify data to support their own beliefs. The latest Rasmussen Reports national telephone survey of American Adults shows that 69% say it’s at least somewhat likely that some scientists have falsified research data in order to support their own theories and beliefs, including 40% who say this is Very Likely. Twenty-two percent (22%) don’t think it’s likely some scientists have falsified global warming data, including just six percent (6%) say it’s Not At All Likely. Another 10% are undecided."

An Echo Chamber Of Climate Science Denial. Here's a story at the Huffington Post: "There was a startling demonstration last week of how quickly messages of climate change denial can spread from the United States to the United Kingdom. The initial trigger was the publication of a paper by Roy Spencer and Danny Braswell of the University of Alabama in Huntsville in the journal 'Remote Sensing', called 'On the Misdiagnosis of Surface Temperature Feedbacks from Variations in Earth's Radiant Energy Balance'. The paper explores an apparent discrepancy between NASA satellite measurements of the amount of radiation escaping the atmosphere and the results of computer models of climate. The authors conclude that the mismatch is due to inaccurate estimates of the "feedbacks" in the climate system which largely control how much global temperature changes in response to the "forcing" exerted by the rise in greenhouse gas concentrations in the atmosphere. However, mainstream climate scientists have poured scorn on the paper because of its assumptions about how clouds affect temperature. In an e-mail to me, Professor Andrew Dessler of Texas A&M University, the author of a key paper on the influence of clouds on climate which appeared in the journal 'Science' last year, explained the main problem with the approach adopted by Spencer and Braswell. To understand this paper, you have to understand the difference between a 'forcing' and a 'feedback'. Forcings are imposed changes to the climate, while feedbacks are processes that respond to changes in the climate and amplify or ameliorate them. So the addition of carbon dioxide to the atmosphere by humans is a forcing - it is simply an imposition on the climate. Water vapour, on the other hand, is a feedback because the amount of water vapour is set by the surface temperature of the planet. As the planet warms, you get more water vapour in the atmosphere, and since water vapour is itself a greenhouse gas, this leads to additional warming."