Thursday, August 5, 2010

Bonnie Lies Over the Ocean, Colin Lies Over the Sea;
Revised 2010 Hurricane Forecast Still Shows Strong Season

Evening Update: Reconnaissance has determined that Colin has strengthened back to a tropical storm with peak winds of 60 mph. The official National Hurricane Center forecast track indicates a possible threat to Bermuda and then later to the Canadian maritimes, although the path of the center is currently expected to pass west of Bermuda and southeast of Newfoundland.

PM Update: As of 2 pm, the remnants of Colin are now getting a 70% chance of regenerating, and an Air Force reconnaissance flight has been sent to investigate.

Original post:
Following a strong early showing by Hurricane Alex, Tropical Storm Bonnie fizzled in the Gulf of Mexico after crossing southern Florida. The remnants of Tropical Storm Colin are now about 300 miles north of the Virgin Islands, where they are given a 50% chance of regaining tropical storm status.

As the usual peak of the hurricane season approaches, the NOAA Climate Prediction Center has lowered the high end of its forecast. The current prediction sets a 70% probability of:
  • 14-20 Named Storms
  • 8-12 Hurricanes
  • 4-6 Major Hurricanes
A Major Hurricane is defined as Category 3 or higher.

Yesterday, the Tropical Meteorology Project at Colorado State University released its revised hurricane season forecast:
  • 18 Named Storms
  • 10 Hurricanes
  • 5 Major Hurricanes
Earlier, WSI, a division of The Weather Channel, also lowered its forecast to a similar range:
  • 19 Named Storms
  • 11 Hurricanes
  • 5 Major Hurricanes
Although slightly lower than earlier forecasts, these all indicate a more active season than average. Overall, NOAA is forecasting a 90% chance of an above-average hurricane season. In addition to record warm Atlantic sea surface temperatures, this is also a reflection of the development of La Niña conditions in the tropical Pacific. La Niña is associated with a reduction in the wind shear in the Atlantic Basin which weakened Bonnie and Colin. There is also a long-term trend for more active hurricane seasons which began in 1995.

Images (click to enlarge): NOAA revised 2010 hurricane season forecast and associated climatic factors from Climate Prediction Center

No comments:

Seasonal Outlook

Latest seasonal forecast: Click here.

Latest 3-month temperature outlook from Climate Prediction Center/NWS/NOAA.