After just 18 hours of life, Tropical Depression 3 degenerated into an open trough of low pressure on Tuesday morning east of the Florida Peninsula, the National Hurricane Center announced at 11 am EDT. The depression had formed on Monday afternoon with a burst of strong thunderstorms atop very warm waters. But surrounded by dry air, TD 3 was unable to leverage that growth into further organization.
At 11 am EDT, TD3’s remnants were centered about 100 miles southeast of St. Augustine, Florida, with top sustained winds of 35 mph. The lowest surface pressure at the center of TD 3 was just 1014 mb, which is not much lower than the surrounding atmosphere.
The Hurricane Hunters did find a pocket of stronger winds associated with thunderstorms well east of TD 3’s center on Tuesday morning. Scatterometer data showed surface winds of 39 knots (45 mph) in this area, and flight-level winds were up to 40 knots. However, these winds were associated with squalls rather than being part of the depression’s central circulation. Closer to TD 3’s center, winds were much weaker, and on their final pass through the storm, the hurricane hunters found that the circulation was no longer closed, with light southwest winds on the northwest side.
A recon VDM does not necessarily mean a circulation is closed, only that a wind shift along one transect coupled with a pressure minimum was found.
— Levi Cowan (@TropicalTidbits) July 23, 2019
Only just now is NW quad being sampled, and the wind is in the wrong direction. #TD3 is likely opening up, if it hasn't already. pic.twitter.com/WYpGcWEXwG
The thunderstorms directly associated with TD 3’s remnants should remain east of Florida over the coming few days. Gusty winds and rainfall of 1-3” could affect northwest parts of The Bahamas on Tuesday. A stout cold front (for midsummer) will push off the North Carolina coast later Tuesday, bringing heavy thunderstorms along the way. TD 3’s remnants are expected to get absorbed by this front offshore.
95L coming to the Gulf of Mexico late this week?
The cold front helping to steer TD 3 offshore is also expected to push into the Gulf of Mexico this week, bringing unusually cool July temperatures to the Deep South. A weak area of low pressure will likely form on Thursday along the front, a few hundred miles south of the Florida Panhandle coast. This system has the potential to develop into a tropical depression late this week as it moves slowly east-northeast to northeast. The low is likely to bring rains of 1 - 3” to portions of northern Florida, southern Georgia, and coastal South Carolina by this weekend.
SSTs in the northern Gulf of Mexico are bit below average for this time of year, due to the lingering effects of Hurricane Barry’s passage earlier this month, but they are still plenty warm for development: near 29°C (84°F). There will be some high wind shear and dry air to the system's north, along the Gulf Coast, which might hamper development. None of our top three models for predicting tropical cyclone development—the GFS, European, and UKMET models—predicted development of this future low into a tropical depression with their 0Z Tuesday runs. The disturbance had a little bit of support for development from the 0Z Tuesday GFS and European model ensemble forecasts—about 10% to 20% of the 70 ensemble members predicted development of a tropical depression by this weekend. In their 8 am EDT Tuesday Tropical Weather Outlook, NHC gave this future low 2-day and 5-day odds of development of 0% and 20%, respectively.
Bob Henson contributed to this post.
