textproduct: Jacksonville

KEY MESSAGES

For the latest NE FL and SE GA Daily Key Messages please visit: https:/www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf

- Scattered Afternoon & Evening Thunderstorms Friday. Hazards: Wind Gusts of 35-45 mph, Frequent Lightning & Heavy Downpours

- Increasing Coverage of Afternoon & Evening Thunderstorms This Weekend. Heavy Rainfall & Localized Flooding Possible on Sunday and Monday, mainly for northeast FL.

- Moderate Rip Current Risk at the Northeast FL Beaches

- Heat Advisory Conditions Possible Towards the Middle of Next Week

UPDATE

No major updates needed on the forecast this evening, but did slightly adjust PoPs to better align with current radar and model trends for after sunset. A few isolated showers/storms will be possible mainly over inland northeast Florida after sunset towards midnight. Tonight, lows will be in the mid to upper 70s.

Higher precipitation chances (especially over north central Florida) and warmer high temperatures than today are forecast for Friday.

SHORT TERM /THROUGH SATURDAY NIGHT/

Main Highlights During Friday and Saturday:

- Heavy Rain and Localized Flood Concerns for NE FL this Weekend - Daily bouts of showers and storms

A Tropical Upper Tropospheric Trough (TUTT) will likely closing off into an upper low on Friday while drifting slowly northwestward into the northeastern Gulf of America. Cooling temperatures aloft associated with this feature, combined with deep tropical moisture (PWATs near or above 2 inches), will increase afternoon and evening thunderstorm coverage compared to recent days. With prevailing northwesterly flow, the Atlantic sea breeze will push inland, focusing the primary corridor of convection near and west of the US- 301 corridor, with the highest coverage across inland northeast Florida and north central Florida.

The upper low is forecast to linger over the northeastern Gulf through Saturday before lifting northeastward late in the weekend as a northern-stream trough approaches the eastern United States. A weak surface low may attempt to develop beneath the upper feature and acquire some subtropical or tropical characteristics as it moves northeast on Sunday. However, confidence in surface low development remains low, with the National Hurricane Center maintaining only a 20 percent chance of tropical development and recent guidance trending less favorable.

Regardless of tropical development, a deep tropical airmass will overspread the region through the weekend, supporting numerous showers and thunderstorms each afternoon and evening, with the greatest coverage expected Sunday. The primary hazard will be periods of heavy rainfall capable of producing localized flooding, especially across northeast and north central Florida where repeated rounds of convection are most likely. Frequent lightning and locally gusty winds will accompany the stronger storms.

Temperatures will remain seasonably hot on Friday and Saturday, with highs in the lower to middle 90s and peak heat index values of 102 to 107 degrees. Increasing cloud cover and widespread convection should hold highs closer to the upper 80s to lower 90s by Sunday while maintaining humid conditions.

LONG TERM /SUNDAY THROUGH THURSDAY/

Main Highlights For Next Week:

- Scattered to Numerous Afternoon Thunderstorms - Potential heat advisory conditions by the middle of next week

he upper low may gradually lift northeastward early next week into the northeast Gulf of America, although some uncertainty remains regarding its exact timing. Regardless, deep tropical moisture will persist across the region through at least Monday as west to southwesterly flow develops behind the departing system. This will support scattered to numerous afternoon and evening showers and thunderstorms, with the greatest coverage Sunday and Monday. Periods of heavy rainfall capable of producing localized flash flooding will remain the primary concern, especially where storms repeatedly track over the same locations.

Sometime late Monday or Tuesday next week per Google Deepmind and some ECMWF AI ensemble members, the upper low should move away as mid-level ridging gradually builds eastward from the west-northwest, resulting in a more typical summertime pattern. While scattered afternoon and evening thunderstorms will continue each day, coverage should gradually decrease. At the same time, increasing heights aloft will allow temperatures to climb back into the middle 90s, with oppressive humidity pushing peak heat index values into the 105 to 110 degree range by midweek. Heat Advisory conditions may become increasingly likely, particularly across inland locations where storm coverage is lower and temperatures climb the highest.

AVIATION /00Z FRIDAY THROUGH 00Z SATURDAY/

Generally VFR conditions expected tonight, with lingering convection near GNV through midnight. Friday, shower and storm chances are highest inland, likely not reaching SSI at this time. For SGJ, CRG and JAX, placed VCTS for now. Highest chances with MVFR to IFR impacts tomorrow afternoon and evening will be at GNV and VQQ. Expect the Atlantic sea breeze to impact the coastal sites around 18-20Z Friday.

MARINE

High pressure will remain to the west near the northern Gulf coast through Friday with west to northwest winds turning east to southeasterly each afternoon due to daily seabreeze circulation. A weak trough will develop over the area Saturday with prevailing wind flow from the southwest with a southerly wind surge in the evening hours elevating winds to near caution levels.

Surface troughing will strengthen Sunday and Monday, with weak low pressure possibly developing over the northeast Gulf. The National Hurricane Center has maintained a low chance, or 20 percent, of weak tropical cyclone formation in the northeast Gulf. Showers and thunderstorms will increase in coverage this weekend, and this weak low pressure center may then progress northeastward across our local waters early next week.

Rip Currents:

Southerly wind surges during the evening hours this weekend may build surf heights to 2-3 feet at the northeast FL beaches and to around 2 feet at the southeast GA beaches, yielding a moderate risk at all area beaches.

FIRE WEATHER

- Fair To Good Dispersions Friday And This Weekend

Wind speeds are forecast to remain below 15 mph through the end of the week. No minimum RH concerns are forecast, with afternoon smoke dispersion values anticipated to be generally fair to good Friday and this weekend. Moisture steadily increases across region into the weekend, with rain and storm chances incrementally increasing through the weekend. Any storms that manage to develop will be capable of producing frequent lightning strikes, high wind gusts, and heavy downpours.

Fog Potential and Other Remarks: Significant fog development is not expected for the next several nights. Gusty and erratic winds will be possible in and near thunderstorms, with occasional outflow boundaries capable of producing sudden wind shifts well away from ongoing convection.

PRELIMINARY POINT TEMPS/POPS

AMG 75 94 74 93 / 20 30 30 70 SSI 79 93 79 93 / 20 20 10 30 JAX 75 95 75 94 / 20 40 10 60 SGJ 76 93 76 93 / 10 30 10 60 GNV 75 93 73 92 / 30 70 50 80 OCF 75 93 74 91 / 30 70 40 90

JAX WATCHES/WARNINGS/ADVISORIES

FL...None. GA...None. MARINE...None.