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Omar intensifies to Category 3, but mostly spares the Lesser Antilles

By: Dr. Jeff Masters, 2:39 PM GMT on October 16, 2008

Hurricane Omar blasted through the Lesser Antilles last night, intensifying into a Category 3 hurricane as it accelerated to the northeast. Fortunately, the eye missed all the islands, as the storm passed through the narrow Anedega Passage between the Virgin Islands and Anguilla. However, the western eyewall did pass over the eastern tip of St. Croix in the U.S. Virgin Islands (Figure 1), bringing hurricane-force winds there. A Personal Weather Station at the Buccaneer Resort on the northeast coast of St. Croix recorded sustained winds of 80 mph at a height of 110 feet. Rainfall there was 6.28" on Thursday, and 9.11" so far today, for a storm total of 15.39". Other wind measurements and total rainfall for the past two days from Omar:

St. Croix airport 39 mph, gusting to 58 mph, 4.56"
Limetree Bay, south side of St. Croix 51 mph, gusting to 71 mph
Limetree Bay CMAN station, St. Croix 53 mph
St. Maartin airport 45 mph, gusting to 67 mph, 7.02"
Anguilla West End Personal Weather Station 45 mph, gusting to 69 mph, 2.88" (elevation 45 feet)

Buoy 41140 (north side of St. Croix, water depth 85 feet) reported 15 foot waves at the time of eyewall passage. The buoy's anemometer was inoperative.

Figure 1. Radar image of Hurricane Omar as its west eyewall passed over the eastern tip of St. Croix, U.S. Virgin Islands. At the time, Omar was a Category 3 hurricane with 120 mph winds.

Omar in historical perspective
Omar is an unusual hurricane in several respects. It's one of only four hurricanes to affect the Lesser Antilles Islands so late in the season. The only hurricanes that occurred later were the Category 3 1867 hurricane that hit Puerto Rico, and two 1999 storms, Category 2 Jose and famed Category 4 "Wrong-way Lenny". Lenny was the only west-to-east moving hurricane on record to affect the Lesser Antilles. Omar's northeasterly motion is highly unusual as well, and I couldn't find any similar storms in the historical record except Lenny.

Omar is headed out to sea and should not affect any other land areas. Steady weakening is forecast, due to increasing wind shear and cooler sea surface temperatures.

Figure 2. Tracks of all October or later hurricanes to affect the northern Lesser Antilles Islands. Light red tracks indicate a minor hurricane, and dark red tracks are for a major hurricane. Image credit: NOAA Coastal Services Center.

Elsewhere in the tropics
Tropical Depression 16 moved ashore over northern Honduras yesterday and dissipated. However, moisture from the depression remains over the region, which could see additional heavy rains of 2-4 inches today. It is possible that the remains of TD 16 could move over the Eastern Pacific and regenerate into a tropical storm. Both the GFDL and UKMET models have indicated this possibility in recent runs.

No computer models are forecasting tropical cyclone development in the Atlantic over the next seven days.

Hurricane Ike relief efforts
There continues to be an urgent need for relief supplies in the wake of Hurricane Ike. I recommend contributions to the portlight.org charity fund, formed by wunderground members to serve the needs of those often bypassed by traditional relief efforts. Contributions are fully tax-deductible, and more details can be found at StormJunkie's blog.

I'll have an update Friday morning.
Jeff Masters
ts omar aruba
ts omar aruba

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