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Tropical Storm Rafael drenching the Lesser Antilles

By: Dr. Jeff Masters, 4:15 PM GMT on October 13, 2012

Tropical Storm Rafael formed late yesterday afternoon over the Lesser Antilles Islands, and is bringing gusty winds and very heavy rains to the islands today. Two-day rainfall amounts of 1 - 3" have been common over the Leeward Islands from Rafael, but the winds have stayed below tropical storm-force so far. Here are some of the peak gusts from Rafael as of noon EDT on Saturday:

Antigua: 37 mph
Martinique: 28 mph
St. Lucia: 39 mph
St. Martin: 26 mph

Satellite loops and radar loops show that Rafael has a large area of heavy thunderstorms to the east and southeast of the center. These thunderstorms are poorly organized, but were beginning to show a more organized spiral banding look late this morning. An upper-level low centered a few hundred miles south of the eastern Dominican Republic is pumping dry air into the west side of Rafael, and is creating a moderate 10 - 20 knots of wind shear.

Figure 1. Radar image out of Martinique from 11:45 am EDT Saturday, October 13, 2012 showed a large area of heavy rain over nearly the entire Lesser Antilles Island chain due to Tropical Storm Rafael. Image credit: Meteo France.

Forecast for Rafael
The shear has dropped since Friday, and is is expected to remain in the moderate range through Monday, which should allow for some slow intensification of Rafael over the next few days. Heavy rains will continue over the entire Lesser Antilles Island chain, plus the Virgin Islands, today through Sunday. Puerto Rico can expect heavy rains on Sunday, but the dry air on the west side of Rafael should keep the Dominican Republic from seeing heavy rains. Rafael's strongest winds will be to the right of the center, and islands of Barbuda, Antigua, Montserrat, St. Kitts and Nevis, St. Barthelemy, St. Eustatis, Anguilla, St. Martin, and Saba may see sustained winds as high as 45 mph Saturday night through Sunday as the strongest bands of Rafael move through. The only island at risk of seeing hurricane-force winds from Rafael is Bermuda. The 11 am EDT wind probability forecast from NHC gave Bermuda a 3% chance of experiencing hurricane-force winds on Tuesday, and a 27% chance of experiencing tropical storm-force winds.

Rafael's place in history
Rafael is the seventeenth named storm of the 2012 Atlantic hurricane season, putting this year in eighth place for busiest Atlantic season since record keeping began in 1851. Here are the busiest Atlantic hurricane seasons on record:

2005 (28 named storms)
1933 (20 named storms, according to a new re-analysis)
1887 (19 named storms)
2010 (19 named storms)
2011 (19 named storms)
1995 (19 named storms)
1969 (18 named storms)
2012 (17 named storms)

There are two weak and short-lived storms from 2012 that stayed far out sea, and would likely have gone unnoticed in the pre-satellite era (before 1960): Tropical Storm Joyce and Tropical Storm Oscar. And while this season has been very busy for total number of named storms, we've had a below-average number of major hurricanes (just Hurricane Michael), and the total destructive power of the 2012 hurricane season as measured by the Accumulated Cyclone Energy (ACE) is only about 20% above average. See our newly-launched Accumulated Cyclone Energy (ACE) page for a storm-by-storm breakdown of this years ACE, plus historical ACE stats for each ocean basin. Thanks go to Angela Fritz for putting this together!

Figure 2. MODIS satellite image of Tropical Storm Patty taken at 1:30 pm EDT Friday, October 12, 2012. At the time, Patty had top winds of 40 mph. High wind shear had exposed the lower-level circulation to view. Late on Saturday morning, wind shear had ripped Patty apart and the storm was declared dead. Image credit: NASA.

Jeff Masters


The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.