Marine Weather and Tide Forecast for Siesta Key, FL

DISCUSSION
The overall forecast remains on track with increased confidence in model solutions. The weak frontal boundary currently stalled across the C Florida Peninsula continues to provide instability in the very moist and unstable atmosphere to produce more rounds of showers and a few thunderstorms.

Main threat from this afternoon's heavy trainers will be a potential for localized flooding of training cells. The flood watch remains in place around the Tampa Bay area with the higher rain chances along the coast especially urban areas that have received heavy rain in last few days. Rainfall totals of 1 to 3 inches, with locally 5+ inches is possible. Interior areas have not seen as much widespread rain in the last week and are still in drought conditions, so will keep those areas out of a watch for now.

Hurricane Isaias in the south central Gulf this afternoon will turn more northward towards the north central Gulf on Friday lifting the stalled front Nward over the N FL Peninsula. Increasing low level winds will become southeast to south across the area Friday to produce faster moving showers/storms, with strong gusty winds, which will decrease the risk for widespread heavy rainfall, but locally heavy rain will remain possible.

As Hurricane Isaias moves into the N Gulf Fri into Sat it will produce new moon high tides above normal values along coastal areas with a coastal flood advisory in effect from Yankeetown to Egmont Key Friday through Saturday morning for tides 1 to 3 feet above astronomical values, and a Storm Surge Watch for coastal Levy county for tides 2 to 4 feet above astronomical values. There will also be an increasing risk for dangerous rip currents at area beaches Friday persisting into Saturday.

Isaias moves into the Deep South this weekend but abundant moisture and southerly flow will combine with afternoon heating to generate numerous showers and scattered thunderstorms. Early next week, drier surface high pressure is expected to decrease rain chances and lower dewpoints.

AVIATION
(18Z TAFS)
Areas of SHRA and ISOLD TSRA over the E Gulf waters continue to move ashore producing MVFR to LCL CIGs /VSBYs in the stronger cells through 00Z with SE-S surface winds. Conditions should improve overnight as the stalled frontal boundary slowly lifts N, but Thu afternoon TSRA to redevelop.

MARINE
The frontal boundary stalled across the central waters will lift to the north with numerous showers and isolated thunderstorms continuing. Hurricane Isaias moving through the Central Gulf will producing increasing hazardous marine conditions tonight, through Friday and continuing Saturday. Expect swells and winds to produce large choppy and confused seas up to around 10 feet. Winds and seas are expected to gradually subside to end of weekend. Surface high pressure will build over the waters early next week with benign conditions developing.

FIRE WEATHER
No fire weather hazards are expected through the weekend as deep tropical moisture will keep minimum afternoon relative humidity values well above critical levels.

PRELIMINARY POINT TEMPS/POPS
TPA 73 87 78 87 / 60 60 30 60 FMY 75 90 77 90 / 60 50 30 50 GIF 73 90 76 90 / 60 60 30 90 SRQ 73 89 76 89 / 60 50 40 60 BKV 69 89 74 90 / 70 60 30 70 SPG 74 87 78 87 / 70 60 30 70

TBW WATCHES/WARNINGS/ADVISORIES
FL...Flood Watch until midnight EDT tonight for Coastal Citrus- Coastal Hernando-Coastal Hillsborough-Coastal Manatee- Coastal Pasco-Inland Citrus-Inland Hernando-Inland Hillsborough-Inland Manatee-Inland Pasco-Pinellas-Sumter.

Coastal Flood Advisory from 8 AM Friday to 8 AM EDT Saturday for Coastal Citrus-Coastal Hernando-Coastal Hillsborough- Coastal Pasco-Pinellas.

High Rip Current Risk from Friday morning through Saturday evening for Coastal Charlotte-Coastal Hillsborough-Coastal Lee-Coastal Manatee-Coastal Sarasota-Pinellas.

Storm Surge Watch for Coastal Levy.

Gulf waters...Small Craft Advisory from 8 PM this evening to 8 PM EDT Saturday for Coastal waters from Tarpon Springs to Suwannee River FL out 20 NM-Waters from Tarpon Springs to Suwannee River FL out 20 to 60 NM.