Invest 94L – a broad area of low pressure located about 800 miles west-southwest of the Cabo Verde Islands – has a window of developing into a tropical depression during the next couple of days before conditions become less favorable. At 8:00 p.m. Tuesday, the National Hurricane Center (NHC) gave 94L a 70 percent chance of development within 48 hours and an 80 percent chance of development within five days.

94L has been moving very slowly westward today. As of 00:00 UTC Wednesday, 94L was centered near 10.5°N 34.6°W. Maximum sustained winds were estimated at 30 knots (35 mph) based on an ASCAT pass from Monday night, with an estimated minimum pressure of 1009 mb. 94L continues to lack a well-defined circulation, and is still embedded in the monsoon trough. Convection has increased during the past few hours near the center, although the convective pattern is not very well organized.

Model support of 94L has dropped significantly since yesterday – possibly due to the system struggling to organize today as expected. Although all GEFS and EPS Ensembles at 00z Tuesday predicted development of at least a tropical depression, both the operational and ensemble members have significantly backed off on development. By late this week, 94L is expected to enter a drier, more stable air mass, with wind shear also expected to increase to over 20 knots. This should cause 94L to degenerate to a remnant low pressure area by the weekend, if development even occurs. The latest model guidance has become more confident in the future track of 94L and nearly all models show 94L remaining well north of the Leeward Islands. After that time, it is unclear about the strength of the subtropical ridge and what track 94L will take when it is near the Bahamas.

I’m becoming increasingly skeptical that 94L will even develop due to the rapidly decreasing model support. I give 94L only a 50 percent chance of development within the next 48 hours – lower than the 70 percent from the NHC. The window for development is not as long as originally predicted, so if a tropical depression does not form by Thursday it is unlikely that any development will occur in the short term. In the long term…the 18z GFS run indicated the possibility of development or re-development northeast of the Bahamas, where conditions could be more favorable. 94L will need watching for the next week at least, even if development does not occur this week.

I will be back tomorrow for another post on 94L, as well as three areas to watch in the East Pacific. The next name on the Atlantic list is Don, and the next three names on the East Pacific list are Eugene, Fernanda and Greg.