CSU: expect a quiet 2012 Atlantic hurricane season; EF-3 tornado confirmed in Texas
Expect one of the quietest Atlantic hurricane seasons since 1995 this year, say the hurricane forecasting team of Dr. Phil Klotzbach and Dr. Bill Gray of Colorado State University (CSU) in their latest seasonal forecast issued April 4. They call for an Atlantic hurricane season with below-average activity: 10 named storms, 4 hurricanes, and 2 intense hurricanes. An average season has 10 - 11 named storms, 6 hurricanes, and 2 intense hurricanes. The 2012 forecast calls for a below-average chance of a major hurricane hitting the U.S., both along the East Coast (24% chance, 31% chance is average) and the Gulf Coast (24% chance, 30% chance is average). The Caribbean is forecast to have a 34% chance of seeing at least one major hurricane (42% is average.) Four years with similar pre-season March atmospheric and oceanic conditions were selected as "analogue" years that the 2012 hurricane season may resemble: 2009, 2001, 1965, and 1957. These years all had neutral to El Niño conditions during hurricane season. The average activity for these years was 9.5 named storms, 4.8 hurricanes, and 2.3 major hurricanes.
Figure 1. Departure of sea surface temperature (SST) from average for April 5, 2012, as computed by NOAA's NESDIS branch. SSTs in the hurricane Main Development Region (red box) were near average to below-average.
Why the forecast of a quiet season?
The CSU team cited two main reasons why this may be a quieter than average hurricane season:
1) La Niña has weakened rapidly over the tropical Eastern Pacific over the past month, and is expected to be gone by the end of April. In its wake, El Niño conditions may develop in time for the August - September - October peak of hurricane season. If El Niño conditions are present this fall, this will likely bring about a quiet Atlantic hurricane season due to increased upper-level winds over the tropical Atlantic creating wind shear that will tend to tear storms apart. The CSU team is leaning towards putting their trust in the ECMWF model, which is predicting that a weak El Niño event will be in place by fall.
2) Sea surface temperatures (SSTs) in the Main Development Region (MDR) for hurricanes from the Caribbean to the coast of Africa between 10°N and 20°N were near average to below average in March 2012. Virtually all African waves originate in the MDR, and these African waves account for 85% of all Atlantic major hurricanes and 60% of all named storms. When SSTs in the MDR are much above average during hurricane season, a very active season typically results (if there is no El Niño event present.) Conversely, when MDR SSTs are cooler than average, a below-average Atlantic hurricane season is more likely. This year's SSTs in the MDR are among the coolest we've seen since our current active hurricane period began in 1995. The cool temperatures are largely due to strong surface winds that blew during the winter over the tropical Atlantic in response to the positive phase of the North Atlantic Oscillation (NAO.) The strong winds stirred up the water, bringing up cooler waters from the depths.
How good are the April forecasts?
The forecasters are using a new statistical model developed last year for making April forecasts, so we don't have a long enough track record to judge how good the new model is. The new model correctly predicted a more active than average season for last year, though called for more activity than was actually observed. However, April forecasts of hurricane season activity are low-skill, since they must deal with the so-called "predictability barrier." April is the time of year when the El Niño/La Niña phenomenon commonly undergoes a rapid change from one state to another, making it difficult to predict whether we will have El Niño, La Niña, or neutral conditions in place for the coming hurricane season. Correctly predicting this is key, since if El Niño, conditions are present this fall, this will likely bring about a quiet Atlantic hurricane season due to increased upper-level winds over the tropical Atlantic creating wind shear that will tend to tear storms apart.
CSU maintains an Excel spreadsheet of their forecast errors ( expressed as a mathematical correlation coefficient, where positive means a skilled forecast, and negative means they did worse than climatology) for their their April forecasts. For now, these April forecasts should simply be viewed as an interesting research effort that has the potential to make skillful forecasts. The next CSU forecast, due by June 1, is the one worth paying attention to. Their early June forecasts have shown considerable skill over the years.
Preliminary NWS survey of the April 3rd, 2012 Dallas, Texas tornadoes
The Fort Worth Weather Service office began surveying tornado damage yesterday from three tornadoes that ripped through the Dallas metro area on Tuesday afternoon. Official storm surveys will be released in the next few days. The Arlington/Kennendale tornado has a preliminary rating of EF-2. They suspect wind speeds peaked around 135mph, a path length of 4.6 miles, and a maximum width of 400 yards (1/4 mile). The Lancaster/Hutchins tornado has a preliminary rating of EF-2, and they suspect it had a maximum width of 200 yards (1/8 mile). The Forney tornado has a preliminary rating of EF-3, with suspected winds up to 150 mph. Surveys are ongoing--there's a lot of damage to see along the tornado paths. These ratings reflect the most severe damage the teams have seen so far. Eighteen tornado warnings were issued by the National Weather Service in Fort Worth on Tuesday, which saved hundreds of lives. There were no fatalities Tuesday, which is welcome news in the wake of 2011's deadly tornado season.
Figure 2. This photo was taken by a NWS Storm Survey team in Lancaster TX on April 4, 2012. It shows EF-2 tornado damage that occurred in parts of Lancaster on April 3, 2012.
Figure 3. From the Weather Service: This is an aerial photograph of a tornado damaged area in Arlington TX. The damage from the tornado that affected Kennedale and Arlington on April 3, 2012 has been given a preliminary rating of EF-2. The photo was taken on Wednesday, April 4, looking to the east.
Portlight disaster relief charity responds to this year's tornadoes
Disaster relief charity portlight.org sent Thomas Hudson to the DFW area yesterday to do damage assessment and determine whether there is a need for Portlight's services in the wake of the tornadoes. Check out the Portlight blog to see the latest updates, and catch up the great work they've been doing in Harrisburg, Illinois in the wake of the devastating EF-4 tornado that hit the town on Leap Day, 2012.
Jeff Masters
Reader Comments
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Thanks much 13
I guess we'll just have to wait and see
So.... what exactly are we worried about Arctic ocean being completely ice free? What does CO2 have to do with anything relating to temperature?
"LinkPrevious climate warmth
So far the ice cores can only provide us a glimpse into the Eemian warm period. But we can already tell that Eemian climate was significantly warmer than the climate of the current Holocene interglacial - probably about 5°C warmer. As ice from the Eemian period (albeit disturbed) has been found at all drill sites, we also know that the Greenland ice sheet did not melt away entirely during the warmth of the Eemian. Close analysis of %u03B418O values in the Eemian ice does indeed suggest that the Eemian Greenland ice sheet was not dramatically smaller than today. "
That's what I think... They are counting on a stronger el nino than will most likely occur.
Unfortunately the NAO, which is very negative now, appears it will go into another extended positive stretch a few days from now...
CO2 is a greenhouse gas- the excessive amounts of greenhouse gases in our environment trap a lot of heat, hence the term greenhouse. This causes the earth to warm. Warm temperatures are notorious for melting ice.
Nice, colorful graphic. Great eye appeal. .... Did you make it yourself? I do not see it being accredited to anyone.
I think the arctic ice melting would cause a lot more harm than good though- as you said, it would be convenient for some, but not so for many
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
440 PM EDT THU APR 5 2012
GAZ103-104-052145-
440 PM EDT THU APR 5 2012
...SIGNIFICANT WEATHER ADVISORY FOR PEA SIZED HAIL AND 40 MPH WINDS
IN WEBSTER AND SUMTER COUNTIES UNTIL 545 PM EDT...
AT 433 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 7 MILES WEST OF KIMBROUGH...MOVING EAST AT 25
MPH.
THIS STORM HAS THE POTENTIAL TO PRODUCE PEA SIZED HAIL...FREQUENT
CLOUD TO GROUND LIGHTNING AND WIND GUSTS TO 40 MPH AS IT MOVES ACROSS
WEBSTER AND SUMTER COUNTIES THROUGH 545 PM EDT. SOME LOCATIONS IN THE
PATH OF THIS STORM INCLUDE KIMBROUGH...WESTON...LEVERETTS...
SEMINOLE...CENTERPOINT...PRESTON...DUMAS...SUMTER ...MADDOX...CROXTON
CROSSROADS...PLAINS...AMERICUS...FRIENDSHIP...SHI LOH AND CONCORD.
HEAVY DOWNPOURS WILL CAUSE PONDING OF WATER ON ROADWAYS.
&&
LAT...LON 3192 8440 3195 8444 3192 8445 3192 8465
3206 8464 3216 8465 3217 8464 3217 8455
3213 8452 3213 8444 3217 8442 3216 8417
3191 8416
TIME...MOT...LOC 2040Z 265DEG 13KT 3202 8474
$$
Where did everyone go that was shouting from the rooftop about the incredible cold snap that was coming next week?
Did the GFS change AGAIN?
Agreed
Not really... Still looks pretty chilly in the east next week
NAO is negative right now and that is why most of the MDR has warmed a little bit in the past couple of weeks.
Absolutely nothing. No need to worry your beautiful mind about things like CO2, the atmosphere, or that hard to understand science stuff.
Now, feel free to go back looking for the edge of the Earth.
Be careful, don't topple over and fall into the mouth of the Great Turtle....
What's up tropicsweatherpr?....it's amazing how fast the SST's can warm in a relatively short period
It's convenient that your graph stops 60 years ago, before most of the contemporary warming and melting occurred.
3/4ths of the minimum arctic ice volume, and 1/3rd of the max arctic ice volume has been lost in the past 33 years.
I do not think the melting of the Arctic sea ice would result in much of a sea level rise. The ice is already on water and thus is already displacing its own weight. There may be a small rise associated with the open water absorbing heat and thus expanding as it does. I, however, am not an expert on any of this. This is just my best guess.
He is referring to Greenland ice caps melting, which is in the arctic, though technically you are correct.
But yes, his numbers reflect some of the more up-to-date models which show anywhere from 3 to 11 feet of sea level rise by 2100.
How is that possible?
Because the rate of Greenland's melting is not linear.
It appears to be at least cummulative at a rate of about an additional negative 20km cubed worth of net melting each year than the previous year.
It may even be melting exponentially, and probably is doing so.
Greenland is another ball game. Should that ice melt, and you are already on the coast, I hope that you also have a floating dock.
Collecting and interpreting environmental indicators play a critical role in our understanding of climate change and its causes. An indicator represents the state of certain environmental conditions over a given area and a specified period of time. Examples of climate change indicators include temperature, precipitation, sea level, and greenhouse gas concentrations in the atmosphere.
BTW, I'm not necessarily predicting that, it just appears that way because the MCS in the gulf is headed southeast toward South Florida and the northern half that was expected to bring thunderstorms up here has completely dissipated so then our only shot of thunderstorms would be the cold front itself.
Of course even though those thunderstorms in the gulf are moving toward South Florida right now you can't guarantee they will actually make it to the coast and impact you guys down there. Mainly its because the models are way off once again tonight as far as placement of convection. Last night I saw at least a few models showing a huge cluster of strong/severe thunderstorms over Central Florida from the gulf between 8 and midnight, but looks like they got it wrong, I consider that solution quite unlikely at this point.
That being said I don't have any model support to make a forecast but I'll give that cluster of storms a 30 to 40% of making it South Florida. It seems like the northern side is tending to erode and the southern part building south where greatest moisture and CAPE are found. Considering this far south Florida and the keys are the most likely to be impacted I believe.
Link
How about - Rising CO2 Levels Linked to Global Warming During Last Deglaciation
ScienceDaily (Apr. 4, 2012) — Many scientists have long suspected that rising levels of carbon dioxide and the global warming that ended the last Ice Age were somehow linked, but establishing a clear cause-and-effect relationship between CO2 and global warming from the geologic record has remained difficult.
A new study, funded by the National Science Foundation and published in the journal Nature, identifies this relationship and provides compelling evidence that rising CO2 caused much of the global warming. (snip)
New Mechanism of Past Global Warming? Thawing Permafrost 50 Million Years Ago Led to Global Warming Events
ScienceDaily (Apr. 4, 2012) — In a new study reported in Nature, climate scientist Rob DeConto of the University of Massachusetts Amherst and colleagues elsewhere propose a simple new mechanism to explain the source of carbon that fed a series of extreme warming events about 55 million years ago, the Paleocene-Eocene Thermal Maximum (PETM), and a sequence of similar, smaller warming events afterward. (snip)
Coral Links Ice Sheet Collapse to Ancient 'Mega Flood'
ScienceDaily (Apr. 3, 2012) — Coral off Tahiti has linked the collapse of massive ice sheets 14,600 years ago to a dramatic and rapid rise in global sea-levels of around 14 metres.
Previous research could not accurately date the sea-level rise but now an Aix-Marseille University-led team, including Oxford University scientists Alex Thomas and Gideon Henderson, has confirmed that the event occurred 14,650-14,310 years ago at the same time as a period of rapid climate change known as the Bølling warming. (snip)
New Understanding to Past Global Warming Events: Hyperthermal Events May Be Triggered by Warming
ScienceDaily (Apr. 2, 2012) — A series of global warming events called hyperthermals that occurred more than 50 million years ago had a similar origin to a much larger hyperthermal of the period, the Pelaeocene-Eocene Thermal Maximum (PETM), new research has found. The findings, published in Nature Geoscience online on April 1, 2012, represent a breakthrough in understanding the major "burp" of carbon, equivalent to burning the entire reservoir of fossil fuels on Earth, that occurred during the PETM.
"As geologists, it unnerves us that we don't know where this huge amount of carbon released in the PETM comes from," says Will Clyde, associate professor of Earth sciences at the University of New Hampshire and a co-author on the paper. "This is the first breakthrough we've had in a long time. It gives us a new understanding of the PETM." The work confirms that the PETM was not a unique event - the result, perhaps, of a meteorite strike - but a natural part of Earth's carbon cycle (snip)
But, hey, that was a nice graph you posted. Very squiggly.
The full articles are available at the links.
Atlantic Tropical Weather Discussion
000
AXNT20 KNHC 051719
TWDAT
TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU APR 05 2012
TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.
BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1700 UTC.
...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF
LIBERIA AT 6N11W TO 3N17W...WHERE THE ITCZ CONTINUES ALONG 2N30W
TO THE COAST OF BRAZIL NEAR THE EQUATOR AT 50W. SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION WITHIN 115 NM N OF THE
ITCZ AXIS AND 160 NM S OF THE MONSOON TROUGH.
...DISCUSSION...
GULF OF MEXICO...
A CLUSTER OF HEAVY SHOWERS AND THUNDERSTORMS IS MOVING ACROSS
THE NE GULF THIS AFTERNOON. THIS AREA OF SCATTERED STRONG
CONVECTION PRECEDES A COLD FRONT CURRENTLY INLAND OVER
MISSISSIPPI...LOUISIANA...AND TEXAS...AND IS ENHANCED BY A
SHORTWAVE UPPER TROUGH MOVING OVER THE FAR SE CONUS. THE
SHORTWAVE IS ASSOCIATED WITH AN UPPER LEVEL LOW OVER ERN
MISSOURI. A PRE-FRONTAL TROUGH IS ANALYZED W OF THE CONVECTION
AREA FROM 30N90W TO 27N94W...WHERE THE OBSERVED WIND SHIFT AND
MODEL GUIDANCE COINCIDE THE BEST. MOSTLY DRY AIR ALOFT COVERS
THE REMAINDER OF THE BASIN PROVIDING MOSTLY FAIR WEATHER
CONDITIONS. GUSTY WINDS AND ROUGH SEAS ARE REPORTED NEAR THE
AREAS OF CONVECTION WITH LIGHTER WINDS AND FLATTER SEAS
ELSEWHERE. EXPECT THIS CONVECTIVE FEATURE TO CONTINUE TO MOVE
ESE THIS AFTERNOON. THE TAIL END OF THE COLD FRONT WILL MOVE
INTO THE BASIN LATER TODAY AND FRIDAY.
Wow... I'd almost forgotten what an epic storm that was
We are at 2701 for the past seven days on high max and high mins.
I beg your pardon!!! :)
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