Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather
By: Dr. Jeff Masters , 2:23 PM GMT on September 30, 2010
The season's fourteenth named storm, Tropical Storm Nicole, lasted only six hours as a tropical storm, but triggered torrential heavy rains that caused havoc from the Caribbean to North Carolina. In Jamaica, flash flooding from Nicole's rains killed at least five, and several other people were swept away by flood waters and are feared dead. The storm cut power to 170,000 island residents, and caused millions of dollars in damages. Nicole dumped 6.93" of rain on Kingston, and 8.62" in the Kingston suburb of Norbrook. Rains were heavier on the western end of the island; 8.47" fell at a personal weather station at Irwindale before the power failed and data was lost.
Figure 1. NASA MODIS satellite image of Tropical Storm Nicole at 2:20pm EDT on 9/29/10. Image credit: NASA.
Figure 2. Flooding in Jamaica from Tropical Storm Nicole. Image credit: Jamaica Observer.
In Southeast Florida, Nicole brought 5.83" of rain to Miami, 9.58" to Plantation Key, and 5.44" to Homestead. However, Florida escaped serious flooding. Cuba also received widespread rain amounts of 5 - 10 inches, but there are no reports of serious flooding on the island. The remnants of Nicole will continue to bring heavy rains to portions of Cuba, the Cayman Islands, and the Bahamas today.
Historic rainfall event for eastern North Carolina
In North Carolina, the the tropical moisture streaming northwards in advance of Nicole has generated an epic rainfall event. Wilmington, NC recorded 20.69 inches of rain over the past four days, and 21.28" for the five-day period ending at 10am EDT this morning. The incredible rainfall totals have eclipsed the city's record for heaviest 4-day and 5-day rainfall events, set in September 1999 during Hurricane Floyd (19.06".) Another 1 - 3 inches of rain are likely today in Wilmington, which might make this month the rainiest month in city history. A series of non-tropical low pressure systems have been developing along a stalled front off the Carolina/North Carolina coast over the past day, and this activity will continue through tonight before the rains finally end late tonight. The historic rainfall is causing severe and damaging flooding across much of eastern North Carolina. Fortunately, eastern North Carolina was under moderate drought conditions prior to this week's rainfall onslaught, so the flooding damage will not be as great as the billions of dollars of damage wrought by Hurricane Floyd.
Figure 3. Radar-estimated precipitation for North Carolina since Sunday shows that the precursor moisture from Nicole has brought widespread rain amounts in excess of ten inches to eastern North Carolina, with over fifteen inches (white colors surrounded by dark purple) near Wilmington.
Heavy rain, flooding, and tornadoes expected from Virginia to New England
The intense plume of tropical moisture streaming northwards along the U.S. East coast will bring heavy rains of 3 - 6 inches across a wide swath of coast from North Carolina northwards to New England today and Friday. The wunderground severe weather map shows that flood warnings are already posted for portions of Pennsylvania, Maryland, and Virginia, and flood watches extend northwards though Delaware, New Jersey, New York, and the rest of New England. Tornado watches have been posted for much of the Mid-Atlantic coast, and NOAA's Storm Prediction Center has put the region in their "slight risk" area for severe weather. One tornado warning has already been issued for coastal Virginia this morning. Three possible tornadoes were reported yesterday in northeastern North Carolina.
Two tropical waves, located 600 - 1000 miles east of the Lesser Antilles Islands, are generating a large area of disorganized thunderstorms. NHC has designated this area Invest 97L this morning. The SHIPS model predicts that wind shear over 97L will remain moderate, 10 - 20 knots, through Saturday morning, then increase to levels marginal for development, 15 - 25 knots, Saturday afternoon through Monday. Some slow development of 97L is likely over this time period, and NHC is giving it a 30% chance of developing into a tropical depression by Saturday. The system is headed west-northwest at 15 mph, and should slow down to about 10 mph by Saturday. 97L will bring heavy rains and strong gusty winds to the Lesser Antilles Islands on Sunday and Monday. The ECMWF model is the only model that develops 97L, and foresees that 97L will track across the northern Lesser Antilles and pass near Puerto Rico on Monday and the eastern Bahamas and Turks and Caicos Islands by Wednesday. There are major differences in how the models handle the steering current forecast for next week, and the long-range track of 97L is highly uncertain at this point.
Figure 4. Morning satellite image of Invest 97L. The upper right portion on the disturbance, centered near 13.5N 45W, is most likely to develop into a tropical depression.
I'll have an update Friday morning.
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