Bryan Norcross: Sprawling non-tropical system bringing heavy rain to parts of Florida
An upper-level non-tropical storm system is developing on schedule off the west coast of Florida. The system looks like a big pinwheel, but it's not a tropical depression or storm. It's a completely different animal.
An upper-level non-tropical storm system is developing on schedule off the west coast of Florida. The system looks like a big pinwheel, but it's not a tropical depression or storm. It's a completely different animal.
The system is well developed about 10,000 feet above the surface, but there is very little reflection of the system in the winds or pressure at the ground. The first requirement for a tropical system is a circulation at the surface of the earth.
INVEST 91L DECLARED IN THE GULF, WITH HEAVY DOWNPOURS EXPECTED IN FLORIDA
Over time, especially over very warm water, an upper-air system can develop a surface circulation, and a tropical depression or tropical storm can form. The National Hurricane Center is giving this one a low chance of that happening the first part of next week.
Tuesday looks like the day the system will have its best chance to transition to a tropical depression or maybe a low-end tropical storm. The forecasts indicate that it will be just south of the Florida Panhandle at that time.
There is no indication at this time it will become very strong, even if it does transition, but of course we’ll watch it to be sure.
The system is battling dry air and will face some hostile upper winds. You can see that most of the thunderstorms have been shoved into the Gulf this morning, although heavy rain is rotating into Southwest Florida and will increase in coverage over the peninsula with the heating of the day.
The strong consensus of the computer forecast models is that the system will drift north over the Gulf. That will keep the right side of the circulation, which is pulling tropical moisture from the south, over Florida. Corridors of heavy rain will move north, meaning some areas could receive 6 or more inches.
Be ready for flooding alerts from the National Weather Service.
WHAT IS A TROPICAL DEPRESSION?
Over the next several days, the rain zone will likely spread into the surrounding states. By the middle of the week, if the system is still around, it could drift west along the Gulf coast, pushed along by the base of the heat-dome high-pressure system to the north.
Stay aware. This broad system will be around for a number of days. Effects will extend well away from the center of circulation.
The dust and hostile upper winds took the system the NHC was tracking off the board. Still, some gusty winds and rain will affect the Cabo Verde Islands.
The conga line of storms continues. There's no threat to land.
Fausto and Genevieve appear to be in the offing. The potential for development southwest of Hawaii has ended.
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