Early 2011 Atlantic Hurricane Season Forecasts
Hi everybody, this is Dr. Rob Carver filling in for Dr. Masters.
A continuation of the pattern of much above-average Atlantic hurricane activity we've seen since 1995 is on tap for 2011, according to the latest seasonal forecast issued April 6 by Dr. Phil Klotzbach and Dr. Bill Gray of Colorado State University (CSU). They are calling for 16 named storms, 9 hurricanes, and 5 intense hurricanes. An average season has 10 named storms, 6 hurricanes, and 2 intense hurricanes. The new forecast is nearly identical to their forecast made in December, which called for 17 named storms, 9 hurricanes, and 5 intense hurricanes. Only six seasons since 1851 have had as many as 17 named storms; 19 seasons have had 9 or more hurricanes. The 2011 forecast calls for a much above-average chance of a major hurricane hitting the U.S., both along the East Coast (48% chance, 31% chance is average) and the Gulf Coast (47% chance, 30% chance is average). The Caribbean is forecast to have a 61% chance of seeing at least one major hurricane (42% is average.) Five years with similar pre-season November atmospheric and oceanic conditions were selected as "analogue" years that the 2011 hurricane season may resemble: 2008, 1999, 1996, 1955, and 2006. The first four years listed all had neutral to La Niña SST's during hurricane season, while 2006 had El Niño SST's. The average activity for these years was 12.6 named storms, 7.8 hurricanes, and 4.8 major hurricanes.
This year, the forecasters have introduced a new statistical model for their April forecasts. There are four components in this model:
1. Average sea-level pressure in March around the Azores in the subtropical Atlantic.
2. The average of January through March sea-surface temperatures (SST's) in the tropical Atlantic off the coast of Africa.
3. Average sea-level pressure in February and March for the southern tropical Pacific ocean west of South America.
4. Forecasts of September's SST in the tropical Pacific using a dynamical model from the European Centre for Medium-Range Weather Forecasts (ECMWF)
The first two components are loosely linked together. Statistical studies have shown that a weaker subtropical high near the Azores, combined with warmer SST's off the coast of Africa in March are associated with weak winds near the surface and aloft from August to October. This decrease in wind speeds reduces wind shear which can disrupt forming storms. These March conditions also are associated with warmer SST's in August to October, which is also favorable for more tropical storms. For this forecast, the first component is strongly favorable for increased hurricane activity, while the second component is weakly negative.
The last two components represent the changes in sea-surface temperature and sea-level pressure that are the El Niño-Southern Oscillation (ENSO). Briefly speaking, El Niño conditions (warm sea-surface temperatures) are not favorable for Atlantic hurricanes. For more info on ENSO and hurricanes, Jeff has this article.
Using the ECMWF model as guidance (see Figure 1), the CSU group believes that SST's in the tropical Pacific will be neutral (less than 0.5°C from normal). This would have a small negative effect on hurricane activity. However, the tropical Pacific sea-level pressure shows that the atmosphere looks like a La Niña event is still going on. This is strongly favorable for Atlantic hurricane activity in the CSU group's model.
Figure 1. Forecasts of El Niño conditions by 20 computer models, made in March 2011. The ECMWF forecast used by the CSU group is represented by the dark orange square. The forecasts for August-September-October (ASO) show that 5 models predict El Niño conditions, 7 predict neutral conditions, and 5 predict a weak to moderate La Niña. El Niño conditions are defined as occurring when sea surface temperatures in the Equatorial Pacific off the coast of South America ( the "Niño 3.4 region) rise to 0.5°C above average (top red line). La Niña conditions occur when SSTs in this region fall to 0.5°C below average. Image credit: Columbia University.
How accurate are the April forecasts? While the formulas used by CSU do well in making hindcasts--correctly modeling the behavior of past hurricane seasons--their April hurricane season forecasts have had no skill in predicting the future. This year's April forecast is using a new system and has not yet produced a verified forecast. The scheme used in the past three years successfully predicted active hurricane seasons for 2008 and 2010, but failed to properly predict the relatively quiet 2009 hurricane season. A different formula was used prior to 2008, and the April forecasts using that formula showed no skill over a simple forecast using climatology. 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.
Figure 2. Accuracy of long-range forecasts of Atlantic hurricane season activity performed by Phil Klotzbach and Bill Gray of Colorado State University (colored squares) and Tropical Storm Risk, Inc. (colored lines). The CSU team's April forecast skill is not plotted, but is less than zero. The skill is measured by the Mean Square Skill Score (MSSS), which looks at the error and squares it, then compares the percent improvement the forecast has over a climatological forecast of 10 named storms, 6 hurricanes, and 2 intense hurricanes. TS=Tropical Storms, H= Hurricanes, IH=Intense Hurricanes, ACE=Accumulated Cyclone Energy, NTC=Net Tropical Cyclone Activity. Image credit: TSR.
2011 Atlantic hurricane season forecast from Tropical Storm Risk, Inc.
The British private forecasting firm Tropical Storm Risk, Inc. (TSR), issued their 2011 Atlantic hurricane season forecast on April 5. They are also calling for a very active year: 14. 2 named storms, 7.5 hurricanes, and 3.6 intense hurricanes. We would round that to 14 named storms, 8 hurricanes, and 4 intense hurricanes. This compares to their forecast issued in December of 15.6 named storms, 8.4 hurricanes, and intense hurricanes. TSR predicts a 55% chance of an above-average hurricane season, 28% chance of a near-normal season, and only a 17% chance of a below normal season. TSR bases their April forecast on predictions that sea surface temperatures this fall in the tropical Atlantic will be above about 0.08°C above average, and trade wind speeds will be about 0.2 m/s slower than average. The decrease in the trade wind speeds is favorable for enhanced hurricane activity, while the forecast SST's are expected to be neutral for hurricane activity.
TSR puts their skill level right next to the forecast numbers: 13% skill above chance at forecasting the number of named storms, 11% skill for hurricanes, and 10% skill for intense hurricanes. That's not much skill, and really, we have to wait until the June 1 forecasts by CSU, NOAA, and TSR to get a forecast with reasonable skill.
Rob's critiques of the April forecasts
I have to note that Jeff and I wrote this article together. He wrote the general framework before the forecasts were issued, while I wrote the details based on the actual forecasts. So the preceding text is a joint production. However, I have a few observations to make that are my responsibility alone.
First, I am disappointed that the CSU group has changed forecast models only after three seasonal forecasts. This makes it very difficult to assess the skill of the current forecast using past performance. This is very important for forecast users, and they do it everyday. For example, I tend to discount a forecast of rain if it comes from a source that over-forecasts rain (The boy who cried wolf problem).
In the documentation that came with the April forecast, the CSU group argue that the hindcasts show the new forecast model has skill. However, I think hindcasts are a poor substitute for real forecasts in understanding the skill of a statistical forecast model, like that of the CSU's group. As Jeff noted, the previous forecast model did well with the hindcasts and yet had mixed results with the actual forecasts. This does not give me confidence that the new forecast model will be superior to the previous model.
From a philosophical viewpoint, I am inherently cautious about statistical forecast models like the one used by the CSU group. Essentially, they look at what happened in the past and use that to predict the future. However, for making forecasts, we assume that the relationships in space and time between the predictors (such as the average March sea-level pressure around the Azores) and the predictands (Atlantic hurricane activity) does not change as we move forward in time. In a world with climate change, that's a tricky assumption to make.
In any event, it is customary in the meteorological community to continue running older forecast guidance models after the introduction of newer models. This allows forecasters and forecast users to leverage their knowledge of the forecast skill of the older model and gain insight into the forecast skill of the new model. The CSU group really should have included the forecast from the previous statistical forecast system in this forecast.
I am uneasy with some of the methodology choices made in implementing the forecast model. Data for the first three predictors was obtained from the Climate Forecast System Reanalysis (CFSR), NOAA's newest and most advanced reanalysis product. However, CFSR data for 2010 and 2011 has not been released yet, so the CSU group used NCEP/NCAR Reanalysis (NNR), NOAA's first-generation reanalysis, to fill in the gaps. Due to differences in design, resolution, etc., CFSR and NNR can have different depictions of the state of the atmosphere. So using NNR's March 2011 average SLP instead of CFSR's could alter the forecast in unexpected ways. It would be interesting to see how CFSR's 2010-2011 data changes the results.
In any event, we will have to wait and see what the Atlantic hurricane season of 2011 brings.
Reader Comments
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And how much do they really care?
Why aren't they enlarging the evacuation-zone?
Why aren't they giving all of the information?
Now they say 'Oops, sorry, things went wrong.'
But they could have done more, especially before things went wrong:
http://www.guardian.co.uk/environment/2011/mar/14 /nuclearpower-energy
Try researching mortality statistics on power generation before making sweeping claims that nuclear power is killing us off.
And try remembering, that I am only stating my opinion. No links required to back that up. I never stated that nuclear power was killing us off. And define "us". Us Americans? Or the "us" families of the Chernobyl liquidators?
Let's talk to the "us" of Fukushima in about three years.
I don't define "us" by political/geographic boundaries.
I have seen PLENTY of Pennsylvania, and West Virginia. Another of many gaping wounds we have inflicted on the planet.
If you're looking for an argument, you won't find it with me.
I have read about the Cuban missile crisis. that could of ended very badly.
I remember those days, when we had Atom bomb drills in school, we all had to hide under our desks. We had them at least once a month. Even when I lived in Europe, we had the same thing. It was estimated in the 1950's and 1960's, that we had the capacity to destroy the world 100 times over. I think more than once would have been redundant.
PRODUCT CHANGES FOR THE 2011 HURRICANE SEASON
Pink is Fire, Green is Flood.
PUBLIC SEVERE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0413 AM CDT SUN APR 10 2011
...SEVERE THUNDERSTORMS EXPECTED OVER PARTS OF THE UPPER MISSISSIPPI
VALLEY FROM MID TO LATE AFTERNOON THROUGH EARLY THIS EVENING...
THE NWS STORM PREDICTION CENTER IN NORMAN OK IS FORECASTING THE
DEVELOPMENT OF A FEW STRONG TORNADOES OVER PARTS OF THE UPPER
MISSISSIPPI VALLEY FROM THE MID-LATE AFTERNOON INTO THE EARLY
EVENING HOURS
THE AREAS MOST LIKELY TO EXPERIENCE THIS ACTIVITY INCLUDE
NORTHEASTERN IOWA
EXTREME NORTHWEST ILLINOIS
WESTERN UPPER MICHIGAN
SMALL PART OF EAST-CENTRAL AND SOUTHEAST MINNESOTA
MUCH OF WISCONSIN
ELSEWHERE...SEVERE STORMS ARE ALSO POSSIBLE FROM THE CENTRAL AND
UPPER GREAT LAKES REGION SOUTHWEST INTO THE EASTERN PARTS OF THE
CENTRAL AND SOUTHERN PLAINS.
...KEY WEATHER PLAYERS...
A POTENT STORM SYSTEM OVER THE CENTRAL AND SOUTHERN ROCKIES IS
EXPECTED TO MOVE EAST INTO THE GREAT LAKES...MIDWEST AND PLAINS
STATES THIS AFTERNOON AND TONIGHT. AHEAD OF THIS FEATURE...WARM AND
MOIST AIR WILL STREAM NORTHWARD AHEAD OF A COLD FRONT... RESULTING
IN SEASONABLY STRONG INSTABILITY NEEDED TO SUPPORT SEVERE
THUNDERSTORMS.
...TIMING...
THUNDERSTORMS OBSERVED DURING THE PRE-DAWN HOURS FROM THE UPPER
MISSISSIPPI RIVER VALLEY INTO THE CENTRAL GREAT LAKES REGION WILL
CONTINUE TO ADVANCE EAST-NORTHEAST THROUGH THE MORNING HOURS.
ATTENTION WILL THEN TURN TO A POTENTIALLY ACTIVE AFTERNOON AND
EVENING ACROSS THE UPPER MISSISSIPPI VALLEY REGION. AS MORNING
CLOUDS DISSOLVE...THE ATMOSPHERE WILL BECOME INCREASINGLY UNSTABLE.
SEVERE THUNDERSTORMS WILL LIKELY DEVELOP FROM NORTHWEST
WISCONSIN...EAST-CENTRAL/SOUTHEAST MINNESOTA AND NORTHEASTERN IOWA
IN THE 200-400 PM PERIOD. THE STORMS WILL THEN DEVELOP/MOVE
THROUGHOUT MUCH OF WISCONSIN...WESTERN UPPER MICHIGAN AND
NORTHWESTERN ILLINOIS THROUGH EARLY EVENING.
...IMPACTS...
MORNING THUNDERSTORMS COULD BRIEFLY ACHIEVE STRENGTH TO PRODUCE
LARGE HAIL...BUT HIGHER-IMPACT SEVERE WEATHER WILL BE ASSOCIATED
WITH AFTERNOON/EVENING STORMS.
THUNDERSTORMS THAT DEVELOP LATER TODAY WILL LIKELY GROW INTO
SUPERCELLS WITH THREATS FOR A FEW STRONG TORNADOES...PARTICULARLY
ACROSS THE MODERATE RISK AREA. ADDITIONALLY...VERY LARGE
HAIL...GREATER THAN HEN EGG SIZE...WILL BE LIKELY ALONG WITH
DAMAGING WIND GUSTS.
STATE AND LOCAL EMERGENCY MANAGERS ARE MONITORING THIS DEVELOPING
SITUATION. THOSE IN THE THREATENED AREA ARE URGED TO REVIEW SEVERE
WEATHER SAFETY RULES AND TO LISTEN TO RADIO...TELEVISION...AND NOAA
WEATHER RADIO FOR POSSIBLE WATCHES...WARNINGS...AND STATEMENTS LATER
TODAY.
..RACY/HART.. 04/10/2011
Its looks like the US is now trapped between the 'Fiery Devil and what will become the deep Blue Sea!
Added to the possible 'desertification problem we can only hope you get some relief from all these bad climatic conditions.
Apparently the Chinese are planing and building a 1000 kilometer water canal/duct to solve some of their drought problems but the US, size of landmass in jeopardy is a very grave problem.
Robert Frost (1874–1963). Miscellaneous Poems to 1920. 1920.
2. Fire and Ice
(From Harper’s Magazine, December 1920.)
SOME say the world will end in fire,
Some say in ice.
From what I’ve tasted of desire
I hold with those who favor fire.
But if it had to perish twice,
I think I know enough of hate
To know that for destruction ice
Is also great
And would suffice.
No, you are wrong. She is not being overly dramatic. Back then the science of nuclear weapons and it effects was still relatively new. The outcome of a nuclear war was often described as the end of the world. Some even believed that the earth could literally explode. Was it scare tactic hyperbole? Probably. By end of the world most meant, the end as we know it; civilizations destroyed, air poisoned for decades if not hundreds of years, soil ruined, etc. No one at the time was thinking of microorganisms or small animals and plant life that might survive. They were talking about mankind and the earth as known at the time.
Is that from your original copy? LOL (Funny, I thought of the same thing when I saw it)
here the newst one
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0623 AM CDT SUN APR 10 2011
VALID 101300Z - 111200Z
...THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON AND EVENING OVER
PARTS OF SOUTHEAST MN...NORTHEAST IA...NORTHWEST IL...MUCH OF
WI...AND WESTERN UPPER MI...
...THERE IS A SLGT RISK OF SVR TSTMS FROM THE GREAT LAKES REGION
INTO CENTRAL TX...
...A LOCALIZED OUTBREAK OF SEVERE THUNDERSTORMS AND TORNADOES IS
POSSIBLE LATER TODAY OVER PORTIONS OF THE UPPER MS VALLEY AND
WESTERN GREAT LAKES REGION...
MORNING WATER VAPOR IMAGERY SHOWS A DEEP UPPER TROUGH OVER THE
WESTERN UNITED STATES. A 90-100 KNOT MID/UPPER LEVEL JET IS MOVING
ACROSS NM AND WILL NOSE INTO THE MIDWEST STATES THIS AFTERNOON.
RAPID SURFACE CYCLOGENESIS WILL ENSUE...WITH A DEEP LOW TRACKING
FROM NORTHWEST IA INTO WESTERN UPPER MI. STRONG AND INCREASING
SOUTHERLY LOW LEVEL WINDS IN THE WARM SECTOR OF THE LOW WILL DRAW
60S DEWPOINTS NORTHWARD AND YIELD A MODERATELY UNSTABLE AIR MASS AS
FAR NORTH AS A WARM FRONT LOCATED ROUGHLY ALONG THE SOUTHERN SHORES
OF LAKE SUPERIOR. THE AREA ALONG AND SOUTH OF THE WARM FRONT WILL
POSE THE GREATEST THREAT OF SIGNIFICANT SEVERE WEATHER LATER
TODAY...INCLUDING THE RISK OF DAMAGING TORNADOES.
CURRENT INDICATIONS ARE THAT MORNING CONVECTION OVER MN/WI WILL
RETREAT NORTHEASTWARD...WITH CONSIDERABLE SUNSHINE DEVELOPING ACROSS
THE REGION THROUGH EARLY AFTERNOON. A RATHER STRONG CAPPING
INVERSION WILL SUPPRESS NEW THUNDERSTORM DEVELOPMENT UNTIL MID-LATE
AFTERNOON AS THE EXIT REGION OF THE UPPER JET WEAKENS THE CAP NEAR
THE SURFACE LOW AND COLD FRONT OVER EASTERN MN/NORTHEAST IA. STORMS
IN THIS AREA ARE EXPECTED TO RAPIDLY BECOME SUPERCELLULAR WITH THE
THREAT OF VERY LARGE HAIL AND TORNADOES. CONVECTION SHOULD RACE
NORTHEASTWARD AT OVER 50 KNOTS ACROSS THE MODERATE RISK AREA DURING
THE AFTERNOON AND EARLY EVENING HOURS. FORECAST SOUNDINGS SHOW
EFFECTIVE HELICITY VALUES OF 250-400 MS/S2 AND VERY STRONG DEEP
LAYER VERTICAL SHEAR. THE COMBINATION OF WEAKENING
CAP...STRENGTHENING WIND FIELDS...AND ENHANCED SHEAR NEAR AND JUST
SOUTH OF THE WARM FRONT WILL POSE A RISK OF STRONG TORNADOES.
INTENSE ACTIVITY MAY SPREAD AS FAR EAST AS WESTERN UPPER MI BEFORE
ENCOUNTERING A MORE STABLE AIR MASS...WHERE WEAKENING IS EXPECTED.
VARIOUS MODEL SOLUTIONS LEND DOUBT REGARDING COVERAGE OF
THUNDERSTORMS WITH SOUTHWARD EXTENT. IT APPEARS LIKELY THAT AT
LEAST ISOLATED SEVERE/SUPERCELL THUNDERSTORMS WILL FORM AS FAR SOUTH
AS EASTERN IA AND NORTHWEST IL. HOWEVER...SOMEWHAT VEERED LOW LEVEL
FLOW APPEARS LIKELY TO DECREASE THE RISK OF SIGNIFICANT TORNADOES
COMPARED TO AREAS FARTHER NORTH OVER WI.
LATER THIS EVENING...MORE NUMEROUS THUNDERSTORMS ARE EXPECTED TO
DEVELOP ALONG THE COLD FRONT FROM MO INTO THE ARKLATEX REGION...AND
EVENTUALLY INTO TX OVERNIGHT. STRONG WINDS ALOFT AND MODERATE
INSTABILITY WILL HELP TO PROMOTE A RISK OF DAMAGING WINDS AND HAIL
IN THESE STORMS THROUGH MUCH OF THE NIGHT.
Is that Lightning?
No, I keep the signed and hermetically sealed copy in the Swiss vault along with my Picassos. ;)
A good place to monitor fire danger is the U.S. Storm Prediction Center. They do Fire Weather Outlooks along with their severe and winter weather event forecasting.
In today's outlook, they delineated an "Extremely Critical Risk" area. Kinda like seeing a PDS - Particularly Dangerous Situation - forecast for severe weather...
...EXTREMELY CRITICAL FIRE WEATHER AREA FOR WRN TX AND THE ERN TX
PANHANDLE...WRN OK...FAR SWRN KS...
and a critical area...
...CRITICAL FIRE WEATHER AREA FOR ERN/SRN NM...WRN/NWRN
TX...WRN/CNTRL OK...NERN/CNTRL KS...
Please click image for the full text.
Published: Sunday, April 10, 2011, 11:00 AM
The Associated Press By The Associated Press The Times-Picayune
Vincent Yu, The Associated Press
A tsunami survivor walks past a centuries-old tablet that warns of the danger of tsunamis in the hamlet of Aneyoshi, Iwate Prefecture, northern Japan. Hundreds of such markers dot the coastline, some more than 600 years old. Collectively they form a crude warning system for Japan.
There was ample evidence of previous historical quakes and tsunami of equal size and strength. It's not that they weren't expected; it's that saving money is always more important than saving lives where corporations are concerned, so they took a calculated risk and built for the very lowest end of possibilities.
As it turns out, they calculated wrong, and now thousands over several generations will likely pay the eventual price. (Though that's not all bad; I imagine TEPCO's executives will get huge cash bonuses next year since millions haven't died. Yet.)
I agree, except I would replace the word "price" with "cost."
Price usually has an endpoint. Cost, like the nuclear situation in Japan, usually doesn't.
I remember hiding under the desk (duck and cover), getting papers in school telling how to survive the aftermath (if you lived), My Dad wondering if we could actually build a shelter underground and not drown, watching TV during the Cuban missile crisis.
Japan's nuclear industry makes standard practice of burning out day laborers, ie still uses essentially untrained workers to do the jobs that cause the highest exposure to radiation.
BTW: The article states that burning out such "independent subcontractors" is still standard practice in most other nations having nuclear powerplants; with an only slightly weaker implication that it still occurs in the US.
What is this map?
"There will be no fighting in the war room!"
satlelight map if i spell that right lol
Thanks KotG didn't read far enough.
Sorry mate, I was talking about the lightning map you posted earlier.
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