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

- Heat and Humidity Builds this Week through the Weekend. Heat Advisory For All of Northeast FL & Southeast GA Coast Today and Wednesday. Heat Advisories Possible Each Afternoon and Evening from Wednesday Through the Weekend

- Widely Scattered Afternoon & Evening TStorms Today- Thursday. A Few Strong Storms Are Possible Across Portions of Southeast GA Today. Scattered Afternoon & Evening TStorms Friday - Sunday

NEAR TERM /THROUGH TONIGHT/

Main Highlights:

- Heat Advisory in effect from Noon to 7PM

- Scattered Thunderstorms This Afternoon and Early Evening, more numerous along the Southeast Georgia coast

- A few strong to severe thunderstorms possible, mainly over SE GA

- Moderate Risk of Rip Currents at Northeast Florida Beaches

High pressure will stretch across south FL through Tonight, with a trough over the southeastern US. Thunderstorms are expected to develop this afternoon due to a combination of diurnal instability, convergence on trough, and sea breeze interactions. The greatest chance for storms, and particularly strong storms, will be over SE GA, due to the trough.

With loss of diurnal heating, convection will dissipate this evening.

With the prevailing flow from the west, the heat will build all the way to the beaches this afternoon. Heat advisory level apparent temperature values are expected across much of the area this afternoon, except for inland SE GA, where A bit of drier air will be in place in the low levels. Lows Tonight in the middle 70s will be common.

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/

Main Highlights This Period:

- Heat Advisory for Northeast Florida and Coastal Southeast Georgia Wednesday. Likely another Heat Advisory for portions of the area Thursday.

- Daily Isolated to Scattered Afternoon Thunderstorms, some of which could be strong West/southwest winds continue Wednesday and Thursday, with higher precipitation chances along the east coast and around the I-10 corridor. Overall, rain chances are around 20-50% both days, a little lower than normal due to suppressive affects from a ridge aloft and the low amounts of moisture in the lower levels. However, we still anticipate scattered thunderstorms each day, with potential for isolated strong storms due to boundary collisions.

Biggest concern during this period will be dangerously hot temperatures and heat index values. High temperatures will be in the mid to upper 90s, even at the east coast beaches. Maximum afternoon heat indices will be around 105-111 degrees, Heat Advisories will be necessary for portions of the area.

LONG TERM /FRIDAY THROUGH MONDAY/

Main Highlights This Period:

- Heat Advisory Potential Each Day, Near Record High Temperatures

- Scattered Afternoon/Evening Thunderstorms Each Day

Near record high temperatures and dangerous heat index values continue Friday onward. Highs will reach the lower to upper 90s, hottest temperatures inland as the Atlantic sea breeze 'cools' down the coast. Again, max afternoon heat indices will be just below or at Heat Advisory criteria each day, peaking around 105-112 degrees.

Overall, precipitation chances continue to be around 20-50% each day, with thunderstorms mainly in the afternoons and evenings as a weak front approaches from the north late this week into the weekend. Storms generally will taper off after sunset each day but there may be some lingering convection through the evening closer to wherever the front is.

AVIATION /18Z TUESDAY THROUGH 18Z WEDNESDAY/

VFR conditions will prevail at area TAF sites this morning.

Convection will develop this afternoon, primarily affecting sites closer to the Atlantic coast. Gusty winds, and restrictions can be expected in and near storms.

VFR conditions are then expected to prevail overnight.

MARINE

Today, Atlantic high pressure will shift south and westward as a trough forms over the southeastern states, with winds prevailing west-southwesterly this morning and more westerly the rest of the week. Each afternoon, the sea breeze will shift winds southeasterly over the near shore waters through the upcoming weekend, followed by southerly evening wind surges which may briefly increase to near caution levels. Scattered thunderstorms may push east from the coast into the coastal waters this evening. Scattered mainly afternoon and evening thunderstorms will remain possible each day through the upcoming weekend.

Rip Currents: A lower end moderate risk may continue at the northeast FL beaches This afternoon as breezy onshore winds develop following the passage of the sea breeze. Low surf heights will likely yield a low risk at the southeast GA beaches. A low risk is then expected from Wednesday through at least Saturday at area beaches as offshore winds and low surf heights prevail.

FIRE WEATHER

- Patchy High Afternoon Dispersions Beginning Tuesday

Light west to southwest winds will keep the Atlantic seabreeze near the coast each day, with lower thunderstorm coverage expected today through Wednesday and forecast to be around 20-50%. A few strong thunderstorms may produce gusty outflows with locally erratic winds.

Temperatures will rise into the mid 90s inland and lower to mid 90s at the coast today and Wednesday with peak heat index values rising to heat advisory levels to about 106-112 into midweek. A heat advisory is in effect for parts of the area today, and may be needed again on Wednesday. Patchy high daytime dispersions expected today into Wednesday as mixing heights increase along with increasing westerly transport winds. Fog Potential: Significant fog development is not expected, with shallow, patchy fog late overnight limited to areas that receive locally heavy rainfall.

CLIMATE

Daily record high temperatures are possible by Thu-Fri:

Thursday, August 13th: KJAX: 99/2023 KAMG: 100/9999 KCRG: 96/2023

Friday, August 14th: KJAX: 99/2023 KGNV: 97/2023 KAMG: 101/2023 KCRG: 98/2023

PRELIMINARY POINT TEMPS/POPS

AMG 95 76 95 76 / 30 30 30 20 SSI 95 78 95 79 / 60 30 30 20 JAX 95 76 95 76 / 50 20 40 20 SGJ 94 77 95 77 / 20 10 40 20 GNV 94 75 94 75 / 10 0 20 10 OCF 94 75 94 75 / 20 10 20 10

JAX WATCHES/WARNINGS/ADVISORIES

FL...Heat Advisory until 7 PM EDT this evening for FLZ021-023-024- 030-031-035-038-120-124-125-132-136>138-140-220-225-232- 233-236-237-240-322-325-333-340-422-425-433-522-533-633. Heat Advisory from noon to 7 PM EDT Wednesday for FLZ021-023- 024-030-031-035-038-120-124-125-132-136>138-140-220-225- 232-233-236-237-240-322-325-333-340-422-425-433-522-533- 633. GA...Heat Advisory until 7 PM EDT this evening for GAZ153-154-165- 166. Heat Advisory from noon to 7 PM EDT Wednesday for GAZ153-154- 162-165-166. MARINE...None.