Fri August 16, 2013
Tropical Moisture, Not a Storm, Will Dump Heavy Rain on Parts of Florida This Weekend.
Good news to report on the tropics today, especially as it relates to Florida. Tropical Storm Erin was downgraded to a depression Friday morning, and the disturbance in the Gulf of Mexico, Invest 92L, is unlikely to impact the Sunshine State directly. It remains to be seen if Erin can survive the long haul across the cooler waters of the central Atlantic. However, the very warm water of the western Gulf of Mexico may still fuel tropical storm formation there over the weekend.
TROPICAL DEPRESSION ERIN
As of 11am Friday, the National Hurricane Center downgraded Erin to a tropical depression, citing a lack of deep convection (or thunderstorms) wrapping around the storm's center to keep the wind speeds up. Satellite data Friday continued to suggest the overall structure of Erin was still intact, but that the available moisture was waning and the center was moving over cooler water. The official forecast for Erin is for it to continue on its west-northwest track, possibly wobbling a bit more north or west at times, through the central Atlantic this weekend. It is entirely possible, however, that Erin will dissipate entirely by early next week due to the cooler waters, drier air, and faster trade winds. No matter the eventual outcome through Monday, Erin is harmless outside of a shipping interest.
The disturbance we've been tracking for days in the Caribbean has emerged in western Gulf and still has a high chance of developing, according to the NHC. Satellite data Friday afternoon was beginning to suggest better organization and the environment nearby is marginally favorable for tropical cyclone formation over the next 24 hours. If a depression or storm were to form, the forecast track and strength for this system is highly uncertain, largely thanks to different steering currents at different levels of the atmosphere. A weaker storm would more likely drift west toward Texas or Mexico Sunday, while a stronger system would be more tempted to turn north toward Louisiana or Mississippi late Sunday or Monday. If a more northward track ensues, increasing amounts of wind shear would most-likely halt development prior to landfall or even cause 92L to weaken.
Regardless of Invest 92L's fate, heavy rain and possible flooding are still projected for much of North Florida and the panhandle thanks to a stalled front and an abundance of tropical moisture. Flash Flood Watches are in effect from the Nature Coast to the First Coast, and for the entire panhandle through Saturday where rainfall rates of 1 to 2 inches per hour are possible with some of the stronger storms. 3-day rainfall totals in the panhandle and near the Georgia border might exceed five inches through Monday.