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

- Isolated to Scattered Afternoon and Evening TStorms Today. Isolated Storms May be Strong with Gusty Winds, Heavy Rainfall, and Frequent Lightning

- Moderate Risk of Rip Currents Today

- Heat and Humidity Builds this Week. Heat Indices Could Briefly Approach 108 Today. Heat Advisories Possible Each Day from Tuesday through Friday

NEAR TERM /THROUGH TONIGHT/

Main Highlights:

- Brief Strong Storms Possible, Wind Gusts to near 40 mph and locally heavy downpours

- Moderate Risk of Rip Currents at Area Beaches

'Drier' air (PWATs near 1.8-2.0") compared to recent days will lower precipitation chances today to around 20-50% as the mean 500 mb ridge extends from the western Atlantic waters across the north central FL coast into the the NE Gulf waters. Weak southwest surface winds will bring in the Gulf sea breeze pretty far inland and promote a slower storm motion, posing a localized flooding risk. Generally we expected isolated to scattered storms firing up as the Gulf and Atlantic sea breezes merge closer to the east coast, with pretty high DCAPE values present, gusty winds will be possible with any isolated strong storm development this afternoon/evening.

With less storm coverage, temperatures will rise to above normal, highs in the lower to upper 90s. Hottest temperatures will be over inland southeast Georgia, where low to very low precipitation chances are. Maximum afternoon heat index values are expected to remain just below Heat Advisory criteria, peaking around 104-107.

Tonight, some patchy fog will be possible over north central Florida and along the I-75 corridor.

SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/

Main Highlights This Period:

- Daily Isolated to Scattered Afternoon Thunderstorms, some of which could be strong

- Increasing Heat Index Values near Heat Advisory levels each day Convective developments are expected to be more inhibited for northeast Florida on Tuesday as high pressure moves across central Florida from out of the east and drier air associated with a northwesterly flow passes over the forecast area. Scattered showers and storms will become relatively more widespread by Wednesday as high pressure moves more into the Gulf and higher levels of moisture cross over portions of southeast Georgia and northeast Florida with higher chances for storms occurring over southeast Georgia and for areas east of I-75. Daily high temperatures will rise up into the mid to upper 90s through midweek with overnight low temperatures dropping down into the mid 70s over inland areas and in the mid to upper 70s along the coastline. Heat index values during this period are expected to rise to be well above 100 Fahrenheit and potentially rising to near Heat Advisory levels.

LONG TERM /THURSDAY THROUGH SUNDAY/

Main Highlights This Period:

- Isolated to Scattered Afternoon Thunderstorm Coverage

- Heat Advisory Potential Each Day

- Higher chances for thunderstorms on Friday

High pressure will move off to the east by Friday resulting in a more southerly and onshore flow going into the weekend, ahead of high pressure ridging moving over the forecast area from out of the Atlantic before the beginning of next week. Daily bouts of isolated to scattered thunderstorms are expected through the period, with convection forecasted to be more widespread on Friday and then diminishing over the weekend. Above average temperatures will continue through the end of the week and into the weekend with daily max temps rising into the upper 90s and heat index values reaching above 110 and likely reaching heat advisory levels during periods of peak heating.

AVIATION /18Z MONDAY THROUGH 18Z TUESDAY/

Southwest winds 5-8 knots inland and near 10 knots at the coast turning east to southeasterly around 18Z behind Atlantic seabreeze. Seabreeze will help initiate afternoon thunderstorms with VCTS noted at all sites and TEMPOs at the Duval sites. High pressure ridge over the area will limit overall storm chances compared to past few days.

Southerly winds after 00Z with storms ending near the coast and inland after 01Z under broken mid and high level clouds from fading storms through the end of the period. Early morning MVFR to IFR restrictions likely at VQQ again with a low chance of fog at GNV.

MARINE

Atlantic high pressure will gradually build westward across our local waters today and persist through the week. Southwesterly flow will prevail over the local waters with an afternoon sea breeze developing over the near shore waters each afternoon, followed by a southerly evening wind surge. Winds and seas are forecast to remain below Caution levels this week. Only isolated afternoon and evening thunderstorms are forecast today through Friday, mainly impacting the near shore waters.

Rip Currents: The afternoon sea breeze will combine with a lingering ocean swell to produce a moderate risk at area beaches this afternoon. Persistent offshore winds will likely lower this risk by midweek.

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 20-40%. 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 Tuesday with peak heat index values rising to heat advisory levels to about 106-110 into midweek. Dispersions improve gradually today compared to Sunday. Patchy high inland dispersions expected Tuesday 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 KCRG: 98/2023

PRELIMINARY POINT TEMPS/POPS

AMG 95 76 95 75 / 10 10 30 20 SSI 92 79 95 79 / 30 0 30 20 JAX 93 75 96 76 / 40 10 30 20 SGJ 92 76 94 76 / 40 10 20 10 GNV 93 74 95 74 / 40 10 10 10 OCF 94 74 95 74 / 30 10 10 0

JAX WATCHES/WARNINGS/ADVISORIES

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