An area of low pressure, packed with tropical moisture, has formed in the eastern Gulf of Mexico. It is poised to produce a great deal of heavy rainfall in Florida and up the entire East Coast during the course of this week as it crawls northward. Areas of flooding are reasonably likely, although it is too soon to pinpoint exactly where.
Florida is likely to catch the brunt of the system’s rain through Monday, before the system spreads over the rest of the Southeast on Tuesday and Wednesday, while rain continues in Florida. By Thursday and Friday, the heaviest rain should focus on the Mid-Atlantic, before reaching New England by Saturday.
The National Hurricane Center is monitoring this system for the possibility that it could develop into a tropical or subtropical storm in the Gulf of Mexico, but the chance is only 30 to 40 percent. “Regardless of subtropical or tropical cyclone formation, this system will enhance rainfall across portions of Florida and the northeastern Gulf Coast during the next few days,” the Hurricane Center said in a discussion early Monday.
If a tropical storm develops, its name would be Alberto. Such formation would be on the early side, considering that Atlantic hurricane season doesn’t begin until June 1. However, Weather.com reports that we’ve seen named storms form before June in four of the past six years.
Tropical systems that develop early in the hurricane season are usually most notable for their rain, rather than wind, and this week’s disturbance is no exception.
As this disturbance comes north, its rainfall will be intensified by a zone of high pressure off the East Coast that, like a pump, will draw moisture from both the Gulf of Mexico and Atlantic Ocean right up the Interstate 95 corridor.
The National Weather Service’s rainfall forecast for the Southeast and the Northeast shows very heavy rainfall totals over the next week.
From Florida to North Carolina, the Weather Service predicts widespread totals of two to four inches over the next several days, with a pocket of four to seven inches in eastern Florida.
From Virginia to eastern Maine, it calls for one to four inches of rain, with locally heavier amounts possible in the central Appalachians. Note that some of the rainfall shown in the Mid-Atlantic is the result of thunderstorms Monday and Tuesday afternoon, rather than the tropical disturbance slated to come through between Wednesday and Friday.
While areas of flooding are possible where the heaviest rainfall develops, this precipitation will, for the most part, be beneficial. From South Florida into eastern Virginia, there are pockets of abnormally dry and drought conditions.
Particularly during the summer months, in the absence of tropical disturbances such as this one, meaningful rainfall can be very hit-or-miss, which increases the likelihood of dry conditions expanding.