2011 Atlantic tropical season survey of predictions

[Promet]

I issued my first outlook for this years hurricane season back on March 20th. NOAA will release it's outlook today and I will add their numbers here after they do.

MY FORECAST FOR THE 2011 TROPICAL SEASON:

15 named storms, 8 hurricanes, 5 major forming in the Atlantic and Caribbean basin.

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Here is a summary of the various predictions by private and public agencies:

PSU 16 names storms (12-20)

PSU experimental 19 named storms

Accu-weather 15 names, 8 hurricanes, 3 major

WSI 15, 8, 4 (2 or 3 hits on U.S.)

TSR 14, 8, 4 (4 land hits)

Weatherbell 13-15 "14" (6 or 7 hits on U.S.)

CSU statistical method 15, 9, 5

CSU analog method 13, 8, 5

CSU GRAY TEAM official 16, 9, 5

Jeff Masters Underground 13, 9, 6

NOAA pending

UK MET OFFICE pending

These average out as follows...

15 named systems, 8.4 hurricanes, 4.5 major with 4.3 hits on the U.S. coastline.

Forecasters disagree on where the greatest threat exists this season, with some pointing the the Western Gulf Coast and others pointing to the Eastern Gulf to North Carolina. While accuracy has been demonstrated in predicting the number of storms in a season in advance, skill is yet to be documented for predicting the greatest coastal zone of risk prior to storm formation.

Last season was a hyper-active Atlantic hurricane season with 19 named tropical cyclones and a number of records set.

The U.S. has been spared from any landfalling hurricanes since 2008, and the hurricane drought in 2009 and 2010 is relatively rare in the historical record. It's interesting to note that the U.S. has not had a three-year stretch without a hurricane landfall since the 1860s. Further, 80 percent of all years in the historical dataset have had at least one hurricane landfall in the U.S. and 43% have multiple hurricane landstrikes.

Therefore the recent good fortune in avoiding landfalling hurricanes or strong tropical storms is not likely to last, and the impact of this season on the coastline of the U.S. is expected to be greater than the lucky quiet period of the last two years, more in line with the historical normal.

Since 1950 an "average" season has 10 named storms, 6 hurricanes, 2 of those being major class.

[CandymanColumbusGA]

I'm going well above "average" with 18 Named storms, 11 Hurricanes of which 5 will be major. I think there will be at least 2 landfalling hurricanes, though it will be interesting to see where they make landfall... It looks like the regions from Panama City to Houston need to be on the look out, with the Outer Banks likely to get a brush with a storm or two sometime in August or September. It'll be interesting to see how I do.

[k***]

^these guys havent found out about the nino yet

[Tornado Lover 89]

I have a question, for sea temperatures is it usually the same for most of the ocean? Or does temperature varies every so many miles? I know it takes more then just warmth for a hurricane to forum but I was just curious.

[CandymanColumbusGA]

^these guys havent found out about the nino yet

That's just it... I don't think we'll go into a full fledged Nino until after October, allowing for storms to blossom without fear of getting sheared apart. That being said, that was a deciding factor in my forecast. If I thought we would go to a Nino by August then the number of storms would be 2/3 of what they are now with only 11-14 named storms. Of course I could be wrong, but I believe Nino will be a little slower to develop allowing for a few more storms to develop.

[ArtRosen]

http://www.noaanews.noaa.gov/stories2011/20110519_atlantichurricaneoutlook.html

The Atlantic basin is expected to see an above-normal hurricane season this year, according to the seasonal outlook issued by NOAA’s Climate Prediction Center – a division of the National Weather Service.

Across the entire Atlantic Basin for the six-month season, which begins June 1, NOAA is predicting the following ranges this year:

• 12 to 18 named storms (winds of 39 mph or higher), of which:
• 6 to 10 could become hurricanes (winds of 74 mph or higher), including:
• 3 to 6 major hurricanes (Category 3, 4 or 5; winds of 111 mph or higher)

Each of these ranges has a 70 percent likelihood, and indicate that activity will exceed the seasonal average of 11 named storms, six hurricanes and two major hurricanes.

“The United States was fortunate last year. Winds steered most of the season’s tropical storms and all hurricanes away from our coastlines,” said Jane Lubchenco, Ph.D., under secretary of commerce for oceans and atmosphere and NOAA administrator. “However we can’t count on luck to get us through this season. We need to be prepared, especially with this above-normal outlook.”

Climate factors considered for this outlook are:

• The continuing high activity era. Since 1995, the tropical multi-decadal signal has brought ocean and atmospheric conditions conducive for development in sync, leading to more active Atlantic hurricane seasons.
• Warm Atlantic Ocean water. Sea surface temperatures where storms often develop and move across the Atlantic are up to two degrees Fahrenheit warmer-than-average.
• La Niña, which continues to weaken in the equatorial Pacific Ocean, is expected to dissipate later this month or in June, but its impacts such as reduced wind shear are expected to continue into the hurricane season.

“In addition to multiple climate factors, seasonal climate models also indicate an above-normal season is likely, and even suggest we could see activity comparable to some of the active seasons since 1995,” said Gerry Bell, Ph.D., lead seasonal hurricane forecaster at NOAA’s Climate Prediction Center.

NOAA’s seasonal hurricane outlook does not predict where and when any of these storms may hit. Landfall is dictated by weather patterns in place at the time the storm approaches. For each storm, NOAA’s National Hurricane Center forecasts how these weather patterns affect the storm track, intensity and landfall potential.

“The tornadoes that devastated the South and the large amount of flooding we’ve seen this spring should serve as a reminder that disasters can happen anytime and anywhere. As we move into this hurricane season it’s important to remember that FEMA is just part of an emergency management team that includes the entire federal family, state, local and tribal governments, the private sector and most importantly the public,” said FEMA Administrator Craig Fugate.

“Now is the time, if you haven’t already, to get your plan together for what you and your family would do if disaster strikes. Visit ready.gov to learn more. And if you’re a small business owner, visit www.ready.gov/business to ensure that your business is prepared for a disaster,” added Fugate.

Hurricane impacts are not limited to the coastline; strong winds and flooding rainfall often pose a threat across inland areas along with the risk for tornadoes.

Next week, May 22-28, is national Hurricane Preparedness Week. To help prepare residents of hurricane-prone areas, NOAA is unveiling a new set of video and audio public service announcements featuring NOAA hurricane experts and the FEMA administrator that are available in both English and Spanish. These are available at http://www.hurricanes.gov/prepare.

The National Weather Service is the primary source of weather data, forecasts and warnings for the United States and its territories. It operates the most advanced weather and flood warning and forecast system in the world, helping to protect lives and property and enhance the national economy. Visit us online at weather.gov and on Facebook.

NOAA’s mission is to understand and predict changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and to conserve and manage our coastal and marine resources. Visit us on Facebook.

[Scuddz]

They're doing the press conference at my building. Pretty neat. I got to give the assistant secratary of Comerce, Dr. Sullivan, a brief on our operations.

[GaWx]

That's just it... I don't think we'll go into a full fledged Nino until after October, allowing for storms to blossom without fear of getting sheared apart. That being said, that was a deciding factor in my forecast. If I thought we would go to a Nino by August then the number of storms would be 2/3 of what they are now with only 11-14 named storms. Of course I could be wrong, but I believe Nino will be a little slower to develop allowing for a few more storms to develop.

My past research of ENSO SST data in relation to tropical activity has suggested that an oncoming Nino often (though not always) results in more adverse conditions developing IN ADVANCE of when SST's reach Nino criteria, whether that be increased MDR dryness/SAL or increased shear. I feel that changes in the 30 day/90 day SOI averages are a better thing to consider as they tend to lead the SST anomaly changes by ~~2 months on average. IF 30 day SOI's start hitting the ~-10 range by, say, AUG, watch out for potentially more SAL and shear during the heart of the season! Others probably prefer to look at the MEI changes. Of course, there is still a question about whether or not there will actually even be a weak Nino this fall/winter. Also, weak Nino's usually don't cause as adverse conditions as stronger ones, which is intuitive.