Disturbance near Panama a threat to develop

An area of disturbed weather, associated with the tail end of a stalled-out cold front, has developed in the south-central Caribbean Sea. This disturbance has a strong potential to develop into a tropical storm by late this week. This morning's QuikSCAT pass revealed an elongated circulation center near 11N 77W, about 300 miles northeast of the Panama Canal. Wind shear is a moderate 10-20 knots over the disturbance, and visible satellite images show that heavy thunderstorm activity is increasing in coverage and intensity across most of the south-central Caribbean.


Figure 1. Current visible satellite image of the Caribbean. Image credit: NOAA.

The forecast
Wind shear is expected to remain in the moderate range, 10-20 knots, over the southern Caribbean during the remainder of the week. Most of the models support additional development of this disturbance, though none of them show anything stronger than a weak tropical storm developing this week. Steering currents are weak, but a slow west-northwest to northwest motion is likely beginning on Tuesday, when an intensifying extratropical storm off the east coast of Florida should impart northwesterly steering currents over the southern Caribbean. I give a high (>50% chance) that this disturbance will develop into Tropical Storm Paloma this week, and a 40% chance that it will eventually become a hurricane. Northeastern Nicaragua and Honduras appear most at risk of heavy rains from the disturbance, although Panama and Costa Rica may also begin receiving heavy rains on Monday. The ECMWF model predicts that the disturbance will move over Jamaica on Friday, and it certainly possible that the Cayman Islands, Jamaica, eastern Cuba, and Haiti may receive heavy rains from this storm by the end of the week. It is unlikely that the disturbance will affect the U.S. this week.

I'll have an update Monday morning.

Jeff Masters