Downpours to escalate in southeastern US, increase risk of flash flooding
Drenching showers and thunderstorms will gather over the southeastern corner of the nation and raise the risk of flash flooding and travel disruptions as tropical and non-tropical features converge into this weekend.
The unfolding pattern may ruin a day at the beach and create hazards for boaters in nearby coastal waters.
This image focused on Florida and the Bahamas was taken on midday Thursday, August 1, 2019. (NOAA / Satellite)
A cool front that had been making slow progress earlier this week will stall along the southern Atlantic coast this weekend.
At the same time, a southward dip in the jet stream will hang out in the same general area.
Meanwhile, tropical moisture will flow northward, while a tropical disturbance lurks in the western Atlantic.
That disturbance is no longer expected to become a tropical depression.
Downpours will focus on parts of Florida and the Bahamas through at least Friday with the risk of localized flooding.
On Tuesday, torrential rain associated with the disturbance triggered flooding in parts of Puerto Rico. During Wednesday, downpours hammered parts of the United States Virgin Islands with heavy rain and flooding.
The non-tropical features alone will be enough to produce drenching downpours and locally gusty thunderstorms.
On Wednesday, a thunderstorm dropped nearly 10 inches of rain near Greensboro, North Carolina, and caused record flooding on North Buffalo Creek. The creek crested just shy of 19 feet and shattered the old record of 16.4 feet.
On Thursday, 3.58 inches of rain fell in one hour at St. Petersburg- Albert Whitted Airport in Florida.
However, the boost in moisture from the tropics has the potential to enhance rainfall greatly in parts of the region.
The area at greatest risk of downpours that can disrupt travel and outdoor plans, as well as cause urban and low-lying area flooding, will extend across the southeastern half of the Florida Peninsula and may brush the coasts of the Carolinas.
A byproduct of the pattern will also agitate surf in the region. Swimmers and rescue personnel should anticipate stronger and more frequent rip currents than average into this weekend.
Some locations in this swath may receive upwards of 4 inches of rain over a two- to three-day period. Much of that rain may fall in several hours, however.
Farther northwest, the non-tropical features will be the main influence on the downpours.
Heavy rainfall from the Florida Panhandle to Virginia, Maryland, Delaware and the southern parts of Pennsylvania and New Jersey this weekend will be more localized but can still lead to isolated urban flooding, travel slowdowns and disruptions to outdoor activities.
Eventually, the southward dip in the jet stream will direct the tropical disturbance progressively farther away from the United States coast later this weekend into early next week.
Despite the risk of localized flooding, some areas ranging from neighborhoods to several counties could stand a thorough soaking. Some portions of the region are experiencing moderate drought conditions, according to the U.S. Drought Monitor.
Elsewhere in the tropical Atlantic, there is a new area of interest. A robust tropical disturbance has the potential to develop prior to reaching the Leeward Islands this weekend into early next week.
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