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 to Numerous Afternoon and Early Evening Thunderstorms Expected on Sunday. Strong Storms are Possible Along the I-95 Corridor, with Wind Gusts of 40-50 mph Possible, Along with Frequent Lightning Strikes and Torrential Downpours.

- Daily Heat Index Values Peak in the 104 - 108F Range through Monday

- Afternoon and Evening Thunderstorm Coverage Shifts South of the I-10 Corridor on Monday.

- Becoming Breezy and Cooler on Tuesday at Coastal Locations with Numerous Showers and Embedded Thunderstorms Possible.

- Small Craft Advisory Conditions Expected Tuesday Afternoon through Thursday Across Our Local Atlantic Waters. High Risk of Rip Currents is Likely at Area Beaches.

SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/

Main Highlights This Period: (Sunday through Monday night)

- Daily Thunderstorm Potential Sunday and Monday, with a few strong storms possible, with gusty winds and heavy rainfall.

- Potential for isolated strong thunderstorms and localized flooding.

- Summertime heat continues with heat index peaking near heat advisory criteria.

Under partly cloudy skies tonight temperatures will gradually cool to the low to mid 70s.

A trough of low pressure will extend south across the southeastern US Sunday, with a high pressure ridge centered to the southeast extending across south FL. Between these features, the low level flow will from the southwest. The flow will be light enough for the east coast sea breeze to move inland to around I95. Convection will start inland Sunday late morning to early afternoon, then work east through the afternoon. The greatest chance for strorms will be along the I95 corridor due to sea breeze interactions.

The trough will dissipate Monday, as high pressure builds to the north northeast. The flow will remain light Monday, but will come more from the northeast to east. This will allow the east coast sea breeze to push well inland, so the convective max in the afternoon will be more toward the central part of the forecast area. Some drier will filter south into SE GA Monday, so higher convective chances expected for NE FL, than SE GA.

Temperatures this period will remain above seasonal averages.

LONG TERM /TUESDAY THROUGH SATURDAY/

Main Highlights This Period Tuesday through Saturday:

- Daily Thunderstorms Potential.

- Elevated Rip Current Risk.

Strong high pressure will build to the north northeast Tuesday through Wednesday night, an inverted trough develops just east of the region. The gradient between these two features will be pinched, leading to an elevated northeast flow. Tuesday and Wednesday will be gusty days along the coast, and across NE FL. Convection potential these two days will be greatest near the coastal trough, due to subsidence from the high.

Inverted troughing will settle overhead Thursday through Saturday. Daily thunderstorm potential will continue due to diurnal heating and convergence associated with this trough.

Near seasonal temperatures are forecast for this period.

AVIATION /00Z SUNDAY THROUGH 00Z MONDAY/

Light rainfall at the Duval County terminals, SSI, and SGJ should end towards 01Z, with MVFR ceilings possible through around 02Z at SGJ. Otherwise, VFR conditions will prevail at the regional terminals through at least 05Z. Low stratus ceilings and fog are expected at VQQ after 05Z, with LIFR conditions possible through around 12Z. MVFR visibilities will likely develop at GNV after 09Z, with some potential for low stratus ceilings to develop towards sunrise as well. Confidence was too low to indicate potential IFR conditions at GNV during the early morning hours on Sunday at this time. Low MVFR ceilings are likely to develop elsewhere towards 13Z, with some potential for a brief period of IFR ceilings through around 15Z. Confidence remains too low to forecast IFR ceilings at this time, with prevailing MVFR ceilings of 1,000 - 2,000 feet expected to persist through around 15Z-16Z at the regional terminals. Showers and thunderstorms are then expected to develop near the regional terminals after 18Z, with PROB30 groups recently inserted in the TAFs for brief surface winds gusts up to 30 knots and IFR visibilities during heavier downpours through around 23Z. Light southerly surface winds this evening will diminish overnight, with west-northwesterly surface winds forecast to develop before 14Z, with sustained speeds increasing to 5-10 knots towards 17Z. The Atlantic sea breeze boundary will develop at coastal locations towards 18Z, shifting surface winds to east-northeasterly around 10 knots at SGJ by 19Z, while southerly surface winds around 10 knots develop at SSI before 20Z.

MARINE

Weakening high pressure south of the area will maintain south to southwest winds and afternoon sea breezes through the rest of the weekend. Daily mid to late afternoon thunderstorms will move offshore, bringing locally strong wind gusts and frequent lightning at times. On Tuesday, a cold front will push south, sending a strong northeasterly wind surge through the local waters and elevating seas. Small craft advisory conditions are probable for the coastal waters starting Tuesday and may continue into Wednesday and possibly Thursday.

Rip Currents: Prevailing offshore winds (except for an afternoon sea breeze) and weak easterly swells will keep a low-end moderate risk of rip currents in effect the next couple of days. Strengthening northeast winds late Monday night into Tuesday will likely result in a high risk at all area beaches through at least Thursday as breakers build.

FIRE WEATHER

- PATCHY TO AREAS OF HIGH DISPERSIONS TUESDAY THROUGH THURSDAY AFTERNOONS.

A trough of low pressure will stretch across the southeastern U.S. this weekend. High pressure will build to the northeast early next week, and strengthen through mid week. As this high builds, an inverted trough will develop east of the area. The gradient between these two features will result in elevated winds Tuesday through Thursday, especially at the coast. An inverted trough will settle overhead late in the week into the weekend. Daily thunderstorm chances are forecast, mainly in the afternoon and evening hours.

PRELIMINARY POINT TEMPS/POPS

AMG 73 93 73 94 / 30 20 10 0 SSI 78 91 77 92 / 40 30 20 0 JAX 75 93 75 93 / 40 60 30 10 SGJ 76 91 76 91 / 30 40 40 20 GNV 74 93 74 93 / 30 50 40 40 OCF 74 93 75 93 / 20 60 40 60

JAX WATCHES/WARNINGS/ADVISORIES

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