STAY INFORMED: Get the (free) First Alert Weather app
Leslie has turned hurricane while spending the week moving very slowly over the Central Atlantic making a gradual curl before heading north then northeast & even east by the weekend. The storm's swell will affect the Florida coastline & much of the U.S. east coast through much of the week & - when combined with onshore flow - result in a high rip current risk at area beaches. Otherwise Leslie will stay far away from any land areas.
A cluster of strong convection persists over the Caribbean. Broad low pressure has developed but t'storm activity lacks much organization & there is a fair amount of mid & upper level shear at the moment. Tropical development over the Caribbean &/or SW Atlantic appears probable next week but the end result is still - as one would expect at this early juncture - far from certain.
The overall pattern through the first two weeks of Oct. will favor tropical development over the Atlantic Basin. The velocity potential anomaly map below indicates expansive green lines - upward motion - spreading from the E. Pacific into the Atlantic Basin, part of a MJO (Madden-Julian Oscillation) pulse. While tropical development could occur just about anywhere, it would appear we especially need to be vigilant of the Caribbean &/or Southwest Atlantic from approximately Oct. 6 through the 16th.
The area of concern matches up with the "hot spots" for Oct. tropical cyclone genesis (development):
CIMMS satellite below shows the extent of dry air but also indicates it doesn't necessarily shut down the basin. Note the considerable dry air between Leslie & Florida which will help to shut down widespread rainfall for Jacksonville/NE Fl./SE Ga. through Friday/Saturday.
Mid & upper level wind shear (enemy of tropical cyclones) analysis (CIMMS). The red lines indicate strong shear:
The Atlantic Basin....
Gulf of Mexico:
Water vapor imagery (dark blue indicates dry air) - notice the dry air spinning into Leslie:
Deep oceanic heat content is seasonably high over the Caribbean, Gulf of Mexico & SW Atlantic as one would expect early in the fall....
Sea surface temp. anomalies:
SE U.S. surface map:
Surface analysis centered on the tropical Atlantic:
Surface analysis of the Gulf:
The E. Pacific remains active....
"Sergio" is strengthening well offshore of Mexico, far to the south of the Baja & will turn northwest over open water through late week then veer back to the west.
© 2020 Cox Media Group