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Western Caribbean disturbance 98L still a threat to develop

By: Dr. Jeff Masters, 5:24 PM GMT on October 10, 2010

An area of disturbed weather (98L) in the Western Caribbean, a few hundred miles east of the coast of Nicaragua, has the potential to become a tropical depression at any time today or Monday as it moves northwestwards toward the Nicaragua/Honduras border at 5 - 10 mph. The disturbance has quite a bit of spin, but an organized surface circulation is not yet apparent on satellite images. Colombia's San Andres Island, to the southwest of 98L's center, is reporting northwest winds, suggesting that 98L may be close to having a closed surface circulation. An a href=http://manati.orbit.nesdis.noaa.gov/ascat_ima ges/cur_50km/zooms/WMBds20.pngASCAT pass from 10:41am EDT this morning confirms that 98L does not have a closed circulation, but it is almost there.Satellite imagery shows a relatively meager amount of intense thunderstorms associated with 98L, and pressures at nearby land stations are falling slowly or not at all. Water vapor satellite loops reveal that considerable dry air surrounds 98L, and this dry air is interfering with development. The Hurricane Hunters are on call to investigate 98L on Monday afternoon.

Figure 1. Afternoon satellite image of 98L.

Forecast for 98L
98L is likely to bring heavy rains to northeastern Honduras and Nicaragua on Sunday and Monday, and to Belize and Mexico's Yucatan Peninsula on Tuesday. Intermittent heavy rains will also affect the Cayman Islands, Jamaica, and Western Cuba over the next three days. The latest SHIPS model forecast calls for wind shear to stay mostly in the moderate range, 10 - 15 knots, through Tuesday. This should allow 98L to reach tropical depression status at any time, and NHC is calling for a 60% chance of 98L becoming a tropical depression by Tuesday morning. The computer models predict 98L will continue on a west-northwest to northwest motion through Tuesday, which would take the storm close to the coast of Belize/Mexico's Yucatan Peninsula by Tuesday. At that point, it is possible that a trough of low pressure over the eastern U.S. will reach far enough south to pull 98L to the northeast across Cuba. None of computer models available as of 1pm EDT developed 98L into a tropical depression. I don't believe 98L will become a depression today, but expect that it will be one by Tuesday.

I'll have an update Monday morning.

Jeff Masters


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