A broad, but not very well organized, area of low pressure has developed over the northeastern Nicaraguan Coast. This low pressure system has been designated Invest 93L, and has a medium chance of becoming Tropical Depression Eighteen or Tropical Storm Philippe by late week. The National Hurricane Center (NHC) gives 93L a 10 percent chance of development within 48 hours, and a 50 percent chance within five days.

As of 00:00 UTC Tuesday, 93L was centered near 14.0°N 83.0°W, and was nearly stationary. Maximum sustained winds were 30 knots (35 mph), with an estimated minimum pressure of 1006 mb. 93L is expected to not move much for the next couple days and remain close to central America. Development into a tropical cyclone appears unlikely in the short term. However, by Thursday, 93L is expected to move northward into the Northwestern Caribbean Sea. Some development is possible at that time. All three major global models – the GFS, ECMWF and UKMET – supported some development with 93L, although the broad nature of the system may limit its ability to consolidate an inner core. It still remains uncertain if, when and where a well-defined circulation will form, and it will be very difficult to forecast track and intensity until that occurs. The 00Z Tuesday SHIPS model run predicted that wind shear will generally be moderate, around 15-20 knots, which is not ideal for development but not very hostile either. The model also predicted mid-level relative humidity values would remain very favorable, above 70 percent, throughout the forecast period. Even though it is now late October, sea surface temperatures are a very warm 30°C (86°F), which is warm enough to support a strong tropical cyclone. There is higher than normal uncertainty with this system, as these broad late-season Caribbean systems are very difficult to predict and tend to develop sooner or later than expected. Residents of Cuba, the Cayman Islands, and Florida should monitor the progress of 93L, although impacts, if any, are highly uncertain. As noted above, the next name on the Atlantic naming list is Philippe.

I will be back with another post tomorrow.