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

- Dangerously Hot & Humid Weather Continues Today. Extreme Heat Warning & Heat Advisory Today, Heat Indices: 110-115

- Severe Thunderstorm Watch through 10 PM. Scattered Strong to Severe Thunderstorms This Afternoon and Evening. Damaging Wind Gusts up to 50-70 mph, Frequent Lightning Strikes, and

- Localized Flooding Due to Heavy Downpours Possible

- Numerous Mainly Afternoon & Evening TStorms through Monday. Daily Rounds of Heavy Downpours Could Result in Localized Flooding

NEAR TERM /UNTIL 7 AM THURSDAY MORNING/

Main Highlights For Today and Tonight:

Surface cold front will sink to near the GA/FL line Tonight. Convection will continue to move south across NE FL this evening, but a gradual weakening trend is expected with loss of diurnal heating. With the proximity of the front, precipitation could continue across north central FL through the night.

Lows in the lower to mid 70s.

SHORT TERM /7 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/

Main Highlights This Period:

- Rounds of Showers and Thunderstorms, Isolated Strong to Severe Storms Possible

- Near Heat Advisory conditions Thursday for Northeast FL & the Coast

By Thursday, the cold front will be draped across SE GA, with the majority of showers and storms south across NE FL, with limited chances over SE GA as drier air filters in behind the boundary. Convective activity may begin to develop during the morning to afternoon hours for portions of north central FL, with further development by the afternoon to evening hours closer to stalled boundary over SE GA. Heavy downpours and strong downbursts will again be possible with any showers and storms that develop as there will still be a good amount of moisture aloft south the stalled boundary. SPC currently has a Marginal Risk for Severe Storms for locations along the boundary in SE GA and south of the boundary across NE FL. With the boundary shifting a bit north along the Altamaha River, a similar pattern will be in place once again on Friday with coverage of numerous and widespread showers and storms once again mainly over NE FL, with isolated strong to severe downbursts possible.

Temperatures will be a bit cooler on Thursday and Friday, but still will still rise into the lower to mid 90s. While it is close, Heat Index values currently aren't hitting Heat Advisory criteria on Thursday, will hold off on issuing a Heat Advisory for Thursday at this time and will reassess with the next package.

LONG TERM /SATURDAY THROUGH WEDNESDAY/

Main Highlights This Period:

- Daily Rounds of Mainly Afternoon and Evening Thunderstorms, Isolated Stong to Severe Storms Possible

The pattern looks to remain active for the upcoming weekend and likely into next week as well, as a frontal zone lingers just north of the region and energy from another upper trough affects the southeastern states. This regime as well as abundant moisture each day will support at least nuermous showers and t'storms daily, as well as strong downburst and heavy rainfall potential. Temperatures overall trend near to slightly below normal during the long term period given the more active convective pattern.

AVIATION /00Z THURSDAY THROUGH 00Z FRIDAY/

The line of thunderstorms near the I10 corridor will sink south across northern FL early in this TAF period, becoming stalled over north central FL overnight.

While JAX area and SSI TAF sites will see a period of quiet weather overnight, thunderstorms will persist at KGNV and KSGJ throughout the night, and day on Thursday. For Jacksonville area TAF sites and KSSI, the thunderstorm potential will increase again Thursday afternoon.

MARINE

Active weather pattern develops today with a surge of southwest winds to Small Craft Exercise Caution levels which will continue through tonight. A frontal boundary will then sink into the Deep South late this week, with this feature becoming stationary during the weekend. Strong to severe thunderstorms will be possible well in advance of this front this afternoon and evening, with stronger storms potentially producing damaging wind gusts, waterspouts, frequent lightning strikes, and torrential downpours. Scattered to numerous thunderstorms will continue across the northeast Florida waters on Thursday and Friday, with less coverage currently forecast for the Georgia waters. Waves of showers and thunderstorms will then overspread all of our local waters during the upcoming weekend. Outside of expected thunderstorm activity, southwesterly winds will prevail with Caution conditions likely through the upcoming weekend.

Rip Currents: Low to marginal moderate risk of rip currents is expected through the end of the week at NE FL and SE GA beaches with surf/breakers of only 1-2 feet due to the offshore flow.

FIRE WEATHER

- Patchy High Daytime Dispersions Inland Through Thursday

- Isolated to Widely Scattered Severe Storms Possible Rest of Week

A frontal boundary will remain over SE GA through Tonight, with showers and thunderstorms expected to persist into the evening hours. An active pattern looks to persist into this weekend as another frontal boundary approaches the region, with daily showers and storms over the area. Mixing of slightly drier air over interior southeast GA through Friday will drop minRH values to around 35-40%, but above any critical thresholds. Patchy high dispersions will be possible on Thursday over southeast GA.

Fog Potential: Significant fog development is not expected during the next several mornings. As mentioned above, isolated to widely scattered strong to severe thunderstorms are possible through the rest of today. Gusts up to 40-60 mph will be possible in these storms as well as erratic winds in/nearby any storms.

PRELIMINARY POINT TEMPS/POPS

AMG 74 96 73 95 / 30 10 20 30 SSI 78 96 77 93 / 50 30 60 50 JAX 76 95 73 93 / 60 70 60 80 SGJ 76 93 74 91 / 50 50 40 80 GNV 75 92 73 91 / 70 60 50 80 OCF 76 91 75 91 / 70 70 40 80

JAX WATCHES/WARNINGS/ADVISORIES

FL...Extreme Heat Warning until 8 PM EDT this evening for FLZ021- 023-024-030-031-035-120-124-125-132-136-137-220-225-232- 233-236-237-322-325-333-422-425-433-522-533-633. Heat Advisory until 8 PM EDT this evening for FLZ038-138-140- 240-340. GA...Extreme Heat Warning until 8 PM EDT this evening for GAZ153- 154-162-163-165-166-264-350-364. Heat Advisory until 8 PM EDT this evening for GAZ132>136-149- 151-152-250. MARINE...None.