FROM THE NATIONAL WEATHER SERVICE:
TODAY AND TONIGHT: Potent and complex system is rapidly developing across the Gulf of Mexico and southeastern US this morning as a deepening upper level trough slides east. Models are consistent with current radar and satellite loops which keep the bulk of the rain and storms associated with the first disturbance over the eastern Gulf of Mexico are expected to remain west and north of our region this morning. However, isolated activity currently over the Florida Straits is forecast to lift north into the region into the morning hours. Overall, expect a relative minimum in activity into at least early afternoon.
* Wind Threat: Due to the very strong developing low level jet, outside of any convection, both today and Friday will be windy days. South Florida should see sustained winds of 20 to 25 mph and frequent gusts 30 to 35 mph. The main convective wind threat will be maximized with the arrival of the squall line late this afternoon and evening, though any convective activity that develops in this environment will be capable of strong, if not severe wind gusts.
* Tornadoes: Morning cloud cover from ongoing Gulf activity may limit daytime heating somewhat, precluding a widespread tornado outbreak. However, with the strong low level jet, veering flow, the environment will be there for any storm to take advantage of with at least an isolated tornado threat. The threat looks to be in two phases: any discrete cells that can develop ahead of the main squall line, and embedded QLCS activity within the squall line as it moves through.
* Heavy Rain: Event total rainfall amounts through Friday afternoon for South Florida are forecast to be look to range between 1 and 3 inches, most of this falling this afternoon and evening with the main squall line. While the majority of South Florida is currently in a minor to moderate drought and can handle some of this rainfall, short period heavy bands may lead to at least minor flooding if they occur. All of South Florida is under a marginal risk for flash flooding.
* Coastal Flooding/High Surf: See the Beach Forecast section below for more detailed information. FRIDAY: Main frontal boundary is expected to be through the region before daybreak Friday, though rain chances will linger through much of the day as we remain under the influence of the deep upper trough. With little instability, the storm threat will be non existent with only gusty and quick moving showers. Outside of showers, sustained winds will be 25 to 30 mph, with frequent gusts over 40 mph possible. A wind advisory will likely be needed for the day on Friday. The passage of the upper level trough late in the day will bring through a secondary boundary to clear out the region late Friday night.