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Forecast of Atlantic Seasonal Hurricane Activity and Landfall Strike Probability for 2013 (Dr. Gray – 8/2/13)

August 9, 2013 Comments off

Forecast of Atlantic Seasonal Hurricane Activity and Landfall Strike Probability for 2013 (PDF)
Source: Department of Atmospheric Science, Colorado State University

Information obtained through July 2013 indicates that the remainder of the 2013 Atlantic hurricane season will be more active than the average 1981-2010 season. We estimate that the remainder of 2013 will have about 8 hurricanes (average is 5.5), 14 named storms (average is 10.5), 75 named storm days (average is 58), 35 hurricane days (average is 21.3), 3 major (Category 3-4-5) hurricanes (average is 2.0) and 7 major hurricane days (average is 3.9). The probability of U.S. major hurricane landfall and Caribbean major hurricane activity for the remainder of the 2013 season is estimated to be above its long-period average. We expect the remainder of the Atlantic basin hurricane season to accrue Net Tropical Cyclone (NTC) activity approximately 140 percent of the seasonal average. We have decreased our seasonal forecast slightly from early April and early June, due to anomalous cooling of sea surface temperatures in the tropical and subtropical eastern Atlantic.

This forecast was based on a newly-developed extended-range early August statistical prediction scheme developed over the previous 33 years. An earlier statistical model that was utilized for several years has also been consulted. Analog predictors were also considered.

Cool neutral ENSO conditions are currently present in the tropical Pacific, and we believe that these conditions are likely to persist for the remainder of the Atlantic hurricane season. While sea level pressure anomalies across the tropical Atlantic have been relatively low during June and July, sea surface temperatures have anomalously cooled in the eastern tropical and subtropical Atlantic. These cooler SSTs are typically associated with less favorable thermodynamic conditions which we believe could cause slightly less TC activity than expected earlier.

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Qualitative Updated Discussion of Atlantic Basin Seasonal Hurricane Activity for 2012

March 25, 2012 Comments off

Qualitative Updated Discussion of Atlantic Basin Seasonal Hurricane Activity for 2012 (PDF)
Source: Tropical Meteorology Project, Colorado State University (Dr. Gray)

We anticipate that the 2012 Atlantic basin hurricane season will have reduced activity compared with the 1981-2010 climatological average. The tropical Atlantic has anomalously cooled over the past several months, and it appears that the chances of an El Niño event this summer and fall are relatively high. This update briefly discusses changes in large-scale ocean/atmosphere patterns that we believe are relevant for the 2012 Atlantic hurricane season.

Qualitative Discussion of Atlantic Basin Seasonal Hurricane Activity for 2012

December 10, 2011 Comments off

Qualitative Discussion of Atlantic Basin Seasonal Hurricane Activity for 2012 (PDF)
Source: Tropical Meteorology Project, Colorado State University (Dr. Gray)

We are discontinuing our early December quantitative hurricane forecast for the next year and giving a more qualitative discussion of the factors which will determine next year’s Atlantic basin hurricane activity. Our early December Atlantic basin seasonal hurricane forecasts of the last 20 years have not shown real-time forecast skill even though the hindcast studies on which they were based had considerable skill. Reasons for this unexpected lack of skill are discussed.

Extended Range Forecast of Atlantic Seasonal Hurricane Activity and Landfall Strike Probability for 2011 (Dr. Gray)

June 1, 2011 Comments off

Extended Range Forecast of Atlantic Seasonal Hurricane Activity and Landfall Strike Probability for 2011 (PDF)
Source: Colorado State University, Tropical Meteorology Project (Dr. William M. Gray)

We continue to foresee well above-average activity for the 2011 Atlantic hurricane season. We are predicting the same levels of activity that were forecast in early April due to the combination of expected neutral ENSO conditions and very favorable atmospheric and oceanic conditions in the tropical Atlantic. We continue to anticipate an above-average probability of United States and Caribbean major hurricane landfall.

Extended Range Forecast of Atlantic Seasonal Hurricane Activity and Landfall Strike Probability for 2011

April 7, 2011 Comments off

Extended Range Forecast of Atlantic Seasonal Hurricane Activity and Landfall Strike Probability for 2011 (PDF)
Source: Colorado State University Tropical Meteorology Project

We continue to foresee well above-average activity for the 2011 Atlantic hurricane season. Our seasonal forecast has been reduced slightly from early December, since there is a little uncertainty about ENSO and the maintenance of anomalously warm tropical Atlantic SST conditions. We continue to anticipate an above-average probability of United States and Caribbean major hurricane landfall.

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