FORECAST OF ATLANTIC SEASONAL HURRICANE ACTIVITY AND LANDFALL STRIKE PROBABILITY FOR 2017
We have maintained our forecast for above-average Atlantic hurricane activity. ENSOneutral conditions appear likely to persist, and most of the tropical and subtropical Atlantic is anomalously warm and is likely to remain so. The probability for major hurricanes making landfall along the United States coastline and in the Caribbean is above-normal due to the forecast for an above-average season. As is the case with all hurricane seasons, coastal residents are reminded that it only takes one hurricane making landfall to make it an active season for them. They should prepare the same for every season, regardless of how much activity is predicted. (as of 4 August 2017) By Philip J. Klotzbach1 and Michael M. Bell2 In Memory of William M. Gray3
This discussion as well as past forecasts and verifications are available online at http://tropical.colostate.edu Jennifer Dimas, Colorado State University media representative, is coordinating media inquiries into this forecast. She can be reached at 970-491-1543 or
[email protected].
Department of Atmospheric Science Colorado State University Fort Collins, CO 80523 Email:
[email protected] Project Sponsors:
1
Research Scientist Associate Professor 3 Professor Emeritus of Atmospheric Science 2
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ATLANTIC BASIN SEASONAL HURRICANE FORECAST FOR 2017 Forecast Parameter and 1981-2010 Median (in parentheses) Named Storms (NS) (12.0) Named Storm Days (NSD) (60.1) Hurricanes (H) (6.5) Hurricane Days (HD) (21.3) Major Hurricanes (MH) (2.0) Major Hurricane Days (MHD) (3.9) Accumulated Cyclone Energy (ACE) (92) Net Tropical Cyclone Activity (NTC) (103%)
Issue Date 6 April 2017 11 50 4 16 2 4 75 85
Issue Date 1 June 2017 14 60 6 25 2 5 100 110
Issue Date 5 July 2017 15 70 8 35 3 7 135 140
Observed Activity Thru July 2017 5 6 0 0 0 0 4 11
Forecast Activity After 31 July 11 64 8 35 3 7 131 129
POST-31 JULY PROBABILITIES FOR AT LEAST ONE MAJOR (CATEGORY 3-4-5) HURRICANE LANDFALL ON EACH OF THE FOLLOWING UNITED STATES COASTAL AREAS: 1) Entire U.S. coastline - 62% (full-season average for last century is 52%) 2) U.S. East Coast Including Peninsula Florida - 38% (full-season average for last century is 31%) 3) Gulf Coast from the Florida Panhandle westward to Brownsville - 38% (fullseason average for last century is 30%)
POST-31 JULY PROBABILITIES FOR AT LEAST ONE MAJOR (CATEGORY 3-4-5) HURRICANE TRACKING INTO THE CARIBBEAN (10-20°N, 60-88°W) 1) 51% (full-season average for last century is 42%)
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Total Seasonal Forecast 16 70 8 35 3 7 135 140
POST-31 JULY HURRICANE IMPACT PROBABILITIES FOR 2017 (NUMBERS IN PARENTHESES ARE LONG-PERIOD FULL SEASON AVERAGES) State Texas Louisiana Mississippi Alabama Florida Georgia South Carolina North Carolina Virginia Maryland Delaware New Jersey New York Connecticut Rhode Island Massachusetts New Hampshire Maine
Hurricane 41% (33%) 38% (30%) 14% (11%) 20% (16%) 61% (51%) 14% (11%) 22% (17%) 35% (28%) 8% (6%) 2% (1%) 2% (1%) 2% (1%) 10% (8%) 9% (7%) 7% (6%) 9% (7%) 2% (1%) 5% (4%)
Major Hurricane 15% (12%) 15% (12%) 6% (4%) 3% (3%) 27% (21%) 2% (1%) 5% (4%) 10% (8%) 1% (1%)