9AM EDT 22 October 2012 Update

The system now known as 99L has a very good chance to develop into a tropical depression or storm later today. It is likely to go over the northern Caribbean, through the Bahams, and then generally stay offshore of the US. It may interact with an approaching trough once near the Mid Atlantic and may become a hybrid nor'easter later. Which would make for very rough seas along the mid Atlantic and northeastern US. But direct land impacts on the US are not likely.

Original Update
Invest 90L is located over 800 miles to the east northeast of the Leeward Islands moving slowly to the west northwest. The tropical wave that is Invest 90L has been interacting with an upper level low with a modest chance for additional development. SSTs are adequate and wind shear is low in the area, however tropical transition of upper level systems can be a slow process at best.

Invest 99L in the central Caribbean Sea has a large circulation envelope within a broad area of lower pressure. NHC is rather bullish on additional development of this system within the next two days, however, there is still a significant area of windshear (30-40 knots) over the Greater Antilles and this shear is not likely to abate for the next 3 days. It should also be noted that large systems usually don't develop rapidly.

SSEC Current Windshear

Convection has been on-again off-again with Invest 99L. Saturday evening deep convection just about totally disappeared but this Sunday morning the convection is in the 'on-again' mode. This system is currently moving to the west at 7 knots and steering currents suggest that movement to the west southwest is possible in the near term. If the system can avoid a northerly component for the next few days (and thus avoid the shear to the north) additional development is possible and rainsqualls over Jamaica, eastern Cuba and Hispaniola are likely.
ED

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