Visible satellite animation suggests a hint of a low-level circulation just to the southwest of Jamaica associated with the tropical disturbance mentioned on the Tropical Weather Outlook from the National Hurricane Center (NHC). There appears to be enough shear at the moment to keep this system from developing. Water vapor satellite loops show high-level westerly winds currently moving toward the disturbance, creating this shear. However, some of the computer models continue to suggest this disturbance will develop.
The above graphic shows some of the computer guidance available to forecasters this afternoon. The green track is from the interpolated National Weather Service (NWS) Global Forecast System (GFSI) that dissipates the system over the Yucatan in around three days. The orange track is the interpolated Hurricane Weather Research and Forecasting (HWFI) model and the cyan track is the interpolated NWS Geophysical Fluid Dynamics Lab (GHMI) model. Both of these models were developed specifically for tropical cyclone forecasting and currently show the disturbance moving into the northern Gulf of Mexico.
The red track is the variable consensus of at least two of the GHMI, HWFI, GFSI and (not shown) the interpolated UK Meteorological Office model, Navy NOGAPS model, Navy version of the GHMI, and the European Center for Medium Range Weather Forecasts model. Some of these models were not available or, in the case of the ECMWF model, the NHC does not have permission to release the track.
Experience suggests that these models do a better job once there is a well-defined circulation center which is something we don’t have at the present time. There will obviously be a lot of attention on this tropical system if it develops and more of the models start showing a northward track toward the oil spill in the Gulf of Mexico.