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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There is a 50/50 chance of an active year at this point, let's wait and see what the atmospheric pattern is on June 1 before making any hasty predictions. Furthermore, just like all coastal Americans should be, Insurance companies should also be ready every year in the event a hurricane visits your insured homes.
The Japan Meteorological Agency has "estimated tsunami arrival" times for places on the coast posted here. The times have passed in some locations — but are just coming up in Sendai-ko and Fukushima prefecture.
I have been watching Holmes on Homes on the Lifestyle channel here. They practically built a house in LA. The codes there are very stringent. Which is very understandable. I find it hard to understand why it's not the same for coastal areas that are effected by hurricanes.
earthquake.usgs.gov
Yeah, we lucked out. The next house my wife and I build will have steel load bearing areas, along with some other protective upgrades.
I read the quake was about 73 miles from the plant
No other quakes have been reported. This is from USGS
Not sure but I do know that all things being equal it does cost more to adhere to the higher Dade county standards than the standard Florida building codes. That being said, if you go from the current or non-existent building codes in some regions to those stringent standards, the cost to build will be higher. In some cases, substantially higher. I think cost concerns should be secondary to safety concerns but, as with anything else, money enters into the equation.
Full list
http://www3.nhk.or.jp/nhkworld/ Click the video link in the upper right. They're looping high-def video of the quake hutting Sendai; it's fascinating to watch the blackouts cascade their way across the city from up high...
and we still gotta deal w/the aftershocks of THESE aftershocks
Link (not in english)
Indeed... what we are witnessing is a slow-motion collision that has been happening since long before our great grandparents were born and will likely continue until long after our great grandchildren have died.
There will be quiet periods during this collision and there will be active periods. Certainly, we seem to be in an active period at the moment...
Hopes and prayers for those who are unfortunate enough to be sitting on top of this collision.
And my wife would kill me, since that would be more of a bunker, instead of a house.
Although, if we win the lotto or something, and she allows me to build a man cave....
WEPA42 PHEB 071439
TIBPAC
TSUNAMI BULLETIN NUMBER 001
PACIFIC TSUNAMI WARNING CENTER/NOAA/NWS
ISSUED AT 1439Z 07 APR 2011
THIS BULLETIN APPLIES TO AREAS WITHIN AND BORDERING THE PACIFIC
OCEAN AND ADJACENT SEAS...EXCEPT ALASKA...BRITISH COLUMBIA...
WASHINGTON...OREGON AND CALIFORNIA.
... TSUNAMI INFORMATION BULLETIN ...
THIS BULLETIN IS FOR INFORMATION ONLY.
THIS BULLETIN IS ISSUED AS ADVICE TO GOVERNMENT AGENCIES. ONLY
NATIONAL AND LOCAL GOVERNMENT AGENCIES HAVE THE AUTHORITY TO MAKE
DECISIONS REGARDING THE OFFICIAL STATE OF ALERT IN THEIR AREA AND
ANY ACTIONS TO BE TAKEN IN RESPONSE.
AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS
REPORTED BY THE JAPAN METEOROLOGICAL AGENCY.
ORIGIN TIME - 1432Z 07 APR 2011
COORDINATES - 38.2 NORTH 142.0 EAST
DEPTH - 40 KM
LOCATION - NEAR EAST COAST OF HONSHU JAPAN
MAGNITUDE - 7.4
EVALUATION
NO DESTRUCTIVE WIDESPREAD TSUNAMI THREAT EXISTS BASED ON
HISTORICAL EARTHQUAKE AND TSUNAMI DATA.
HOWEVER - EARTHQUAKES OF THIS SIZE SOMETIMES GENERATE LOCAL
TSUNAMIS THAT CAN BE DESTRUCTIVE ALONG COASTS LOCATED WITHIN
A HUNDRED KILOMETERS OF THE EARTHQUAKE EPICENTER. AUTHORITIES
IN THE REGION OF THE EPICENTER SHOULD BE AWARE OF THIS
POSSIBILITY AND TAKE APPROPRIATE ACTION.
THIS WILL BE THE ONLY BULLETIN ISSUED FOR THIS EVENT UNLESS
ADDITIONAL INFORMATION BECOMES AVAILABLE.
THE JAPAN METEOROLOGICAL AGENCY MAY ALSO ISSUE TSUNAMI MESSAGES
FOR THIS EVENT TO COUNTRIES IN THE NORTHWEST PACIFIC AND SOUTH
CHINA SEA REGION. IN CASE OF CONFLICTING INFORMATION... THE
MORE CONSERVATIVE INFORMATION SHOULD BE USED FOR SAFETY.
THE WEST COAST/ALASKA TSUNAMI WARNING CENTER WILL ISSUE PRODUCTS
FOR ALASKA...BRITISH COLUMBIA...WASHINGTON...OREGON...CALIFORNIA.
WEHW42 PHEB 071442
TIBHWX
HIZ001>003-005>009-012>014-016>021-023>026-071642 -
TSUNAMI INFORMATION STATEMENT NUMBER 1
NWS PACIFIC TSUNAMI WARNING CENTER EWA BEACH HI
442 AM HST THU APR 07 2011
TO - CIVIL DEFENSE IN THE STATE OF HAWAII
SUBJECT - TSUNAMI INFORMATION STATEMENT
THIS STATEMENT IS FOR INFORMATION ONLY. NO ACTION REQUIRED.
AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS
ORIGIN TIME - 0432 AM HST 07 APR 2011
COORDINATES - 38.2 NORTH 142.0 EAST
LOCATION - NEAR EAST COAST OF HONSHU JAPAN
MAGNITUDE - 7.4 MOMENT
EVALUATION
BASED ON ALL AVAILABLE DATA A DESTRUCTIVE PACIFIC-WIDE TSUNAMI IS
NOT EXPECTED AND THERE IS NO TSUNAMI THREAT TO HAWAII. REPEAT. A
DESTRUCTIVE PACIFIC-WIDE TSUNAMI IS NOT EXPECTED AND THERE IS NO
TSUNAMI THREAT TO HAWAII.
THIS WILL BE THE ONLY STATEMENT ISSUED FOR THIS EVENT UNLESS
ADDITIONAL DATA ARE RECEIVED.
We can only hope!
From: NOAA/NWS/West Coast and Alaska Tsunami Warning Center
Subject: Tsunami Information Statement #1 issued 04/7/2011 at 7:40AM PDT
A strong earthquake has occurred, but a tsunami IS NOT expected along the California, Oregon, Washington, British Columbia, or Alaska coast. NO tsunami warning, watch or advisory is in effect for these areas.
Based on the earthquake magnitude, location and historic tsunami records, a damaging tsunami IS NOT expected along the California, Oregon, Washington, British Columbia, and Alaska coasts. At coastal locations which have experienced strong ground shaking, local tsunamis are possible due to underwater landslides.
At 7:32 AM Pacific Daylight Time on April 7, an earthquake with preliminary magnitude 7.4 occurred near the east coast of Honshu, Japan . (Refer to the United States Geological Survey for official earthquake parameters.)
Pacific coastal regions outside California, Oregon, Washington, British Columbia, and Alaska should refer to the Pacific Tsunami Warning Center messages for information on the event.
This will be the only statement issued for this event by the West Coast/Alaska Tsunami Warning Center unless conditions warrant. See the WCATWC web site for basic tsunami information, safety rules, and a tsunami travel time map and table. (NOTE: Travel time maps and tables indicate forecasted times only, not that a wave was generated.)
http://www.bbc.co.uk/news/business/market_data/ov erview/default.stm
We did CBS with every 3rd row rebarred and poured with a poured tiebeam. Considering my Grandfather built his old CBS home back in the 1950's with far less rebar and poured concrete and it went thru Donna with 140+ mph winds and only a couple lost shingles, I feel pretty safe. If I had the money though I'd do exactly what you're describing. I'm a big proponent of overkill!!
Region name Miyagi-ken Oki
Depth about 40 km
Magnitude 7.4
Tsunami Warning/Advisory
Issued at 23:34 JST 07 Apr 2011
******************Headline******************
Tsunami Warnings (Tsunami) have been issued for the following coastal regions of Japan:
MIYAGI PREF.
Evacuate immediately to safe place away from the shore in the above coastal regions.
Tsunami advisories are currently in effect in other coastal regions of Japan.
*******************Text********************
Tsunami Warnings have been issued for the following coastal regions of Japan:
*MIYAGI PREF.
Evacuate immediately to safe place away from the shore in the above coastal regions.
Tsunami Advisories have been issued for the following coastal regions of Japan:
PACIFIC COAST OF AOMORI PREF.
*IWATE PREF.
FUKUSHIMA PREF.
IBARAKI PREF.
Tsunamis are expected to arrive imminently in the following coastal regions of Japan
(coastal regions shown above with * marks):
MIYAGI PREF.
IWATE PREF.
***********About Tsunami Forecast************
Tsunami height is expected to be up to 2 meters. Caution advised.
Tsunami height is expected to be about 0.5 meters. Attention advised.
******* Earthquake Information ********
Occurred at 23:32 JST 07 Apr 2011
Region name MIYAGI-KEN OKI
Latitude 38.2N
Longitude 142.0E
Depth about 40 km
Magnitude 7.4
Tsunami Arrival times.
Basically, I want something that can handle just about whatever the gulf can realistically throw at me. For me to get Cat 5 sustained winds, it would have to be an absurd cat 5 on landfall (talking Camille strength), huge (think Ike-size), and go directly over me. Yes, it could happen, but its doubtful.
(High Tide Time and Estimated Tsunami Arrival Time at each place)
Issued at 23:35 JST 07 Apr 2011
High Tide Time and Estimated Tsunami Arrival Time at each place
Exercise extreme caution if a tsunami arrives at high tide, as this boosts the height of waves.
Tsunami Forecast Region/
Tsunami Observation Site High Tide Time Estimated Tsunami
Arrival Time
MIYAGI PREF. (*1)
Ishinomaki-shi Ayukawa 05:08 JST 08 Apr 23:40 JST 07 Apr
Sendai-ko 05:13 JST 08 Apr 00:10 JST 08 Apr
PACIFIC COAST OF AOMORI PREF. 00:20 JST 08 Apr
Hachinohe 04:52 JST 08 Apr 00:40 JST 08 Apr
Mutsu-shi Sekinehama 04:50 JST 08 Apr 00:50 JST 08 Apr
Mutsuogawara-ko 04:50 JST 08 Apr 00:30 JST 08 Apr
IWATE PREF. (*1)
Miyako 04:54 JST 08 Apr 00:00 JST 08 Apr
Ofunato 05:01 JST 08 Apr 23:50 JST 07 Apr
Kamaishi 05:03 JST 08 Apr 00:00 JST 08 Apr
Kuji-ko 04:54 JST 08 Apr 00:20 JST 08 Apr
FUKUSHIMA PREF. 23:50 JST 07 Apr
Iwaki-shi Onahama 05:28 JST 08 Apr 00:20 JST 08 Apr
Soma 05:19 JST 08 Apr 00:20 JST 08 Apr
IBARAKI PREF. 00:20 JST 08 Apr
Oarai 05:25 JST 08 Apr 00:30 JST 08 Apr
Kamisu-shi Kashima-ko 05:35 JST 08 Apr 00:30 JST 08 Apr
*1 mark: Arrival of tsunami inferred.
Tsunami Warnings and/or Advisories are in currently effect for the following coastal regions of Japan:
MIYAGI PREF.
PACIFIC COAST OF AOMORI PREF.
IWATE PREF.
FUKUSHIMA PREF.
IBARAKI PREF.
Although there may be slight sea-level changes in coastal regions other than the above, no tsunami damage is expected in those coastal regions.
Earthquake Information
Occurred at 23:32 JST 07 Apr 2011
Region name MIYAGI-KEN OKI
Latitude 38.2N
Longitude 142.0E
Depth about 40 km
Magnitude 7.4
A home has collapsed and an 85y.o woman is trapped under the rubble. All tsunami alerts ans warning have now been lifted.
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