Central American disturbance less organized

A tropical disturbance (95L) near 11N, 79W, just north of Panama, has remained nearly stationary and become less organized over the past 24 hours. The amount of heavy thunderstorm activity has decreased, and the winds from the latest QuikSCAT satellite pass at 6:11pm EST last night revealed top winds of only 20-30 mph. An ill-defined and elongated surface circulation was apparent in the QuikSCAT data, and some evidence of rotation can be seen on the latest visible satellite loop of the region.


Figure 1. preliminary model tracks for the Panama disturbance, 95L.

Water temperatures are a warm 28C, and wind shear remains around 10 knots, which is low enough to allow some slow development over the next two days. It is possible a tropical depression could form on Monday, as wind shear is expected to remain low over the extreme southern Caribbean. None of the models are forecasting that 95L will develop into a depression--with the exception of the 00Z run of the GFDL model, which has a very unrealistic-looking forecast of a Cat 2 hurricane on Monday hitting Nicaragua. The Hurricane Hunters are on call to investigate the system on Monday afternoon, but given the current poor organization of the system, I doubt a flight will be needed. Steering currents are weak, but a slow westward motion is indicated by most of the models. The system appears to be a threat primarily to Nicaragua, Costa Rica, Honduras, and Panama. Any northward movement of the storm would bring it into a area of high wind shear that would quickly tear it apart.

I'll be back Sunday morning with an update.
Jeff Masters