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 Advisory Sunday Afternoon: Peak Afternoon Heat Index Values Sunday: 105- 110

- Increased Coverage of Afternoon & Evening Thunderstorms Sun - Tues. Strong to Isolated Severe Storms Possible Each Day. Heavy Downpours and Localized Flooding Possible

UPDATE

Active evening of convection is slowly coming to an end for most, though some activity will continue over the next few hours over southeast GA with any lingering boundary collisions. Heat Advisory has been cancelled for today, with yet another one already issued for the St. Johns River Basin and coast tomorrow - despite temps expected to be a few degrees lower Sunday, higher humidity and less dry air mixing will yield similar heat indices again tomorrow. Debris clouds otherwise slowly dissipate overnight with lows in the mid 70s most common.

SHORT TERM /THROUGH MONDAY NIGHT/

Main Highlights During This Period:

- Increased Storm Chances Sunday and Monday - Heat Advisory along the I-95 corridor of SE GA/NE FL for Sunday

Southwest steering flow off the Gulf coupled with an approaching front from the north will increase moisture across the area Sunday and Monday, prompting higher convective chances then we've seen this past week. Westerly surface winds will allow the Gulf sea breeze to push far inland, reaching the Atlantic sea breeze closer to I-95, leaving higher strong storm potential in that region as well as closer to the front across southeast Georgia. Still going to be pretty hot on Sunday, with highs in the mid to upper 90s, with the hottest apparent temperatures near the east coast, where values will approach Heat Advisory criteria. Will issue Heat Advisory for the I- 95 corridor of NE FL/SE GA and the St. Johns River Basin south of JAX.

Monday, shower and storm coverage increases further as the aforementioned front sinks further south into central Georgia. Highest storm chances will again be closer to the front, along and north of I-10, and also along the northeast Florida coast where the sea breezes interact. The primary strong storm threats will be gusty winds and heavy rainfall potentially causing flooding concerns. Again, convection may linger past sunset across southeast Georgia mainly. Temperatures will lower a few degrees Monday, with highs in the lower to mid 90s.

Isolated storms may linger after sunset both Sunday and Monday nights closer to where the front is, over southeast Georgia.

LONG TERM /TUESDAY THROUGH SATURDAY/

Main Highlights During This Period:

- High storm chances continue Tuesday - Heat re-builds into the region Wednesday through Friday

Numerous showers and storms are forecast again for Tuesday as the front sits across South Georgia, then slowly dissipates through the rest of the week. Most of the area is under a 'Marginal' risk of Excessive Rainfall on Tuesday, after several days of heavy rain there will be a threat of localized flooding, especially near the front and over flood prone areas.

Storm chances are generally lower Wednesday onward as northwesterly steering flow brings in drier air aloft, precipitation chances will be around 20-40%. Temperatures will gradually rise again each day through Friday back into the mid to upper 90s, with a risk of Heat Advisory headlines once again, mainly across Northeast Florida.

AVIATION /00Z SUNDAY THROUGH 00Z MONDAY/

TSRA is slowly coming to an end for northeast FL terminals, with some lingering VCTS to continue through the next several hours as storms dissipate. The best chance for more enhanced impacts besides VCTS over the next few hours would be at SSI, where a TEMPO group remains through at least 01Z. Otherwise, VFR is expected to return by about 02-03Z with no operational impacts expected overnight. Convection is expected to spread from southwest to northeast once again Sunday, with PROB30 groups included again as a similar setup expected as compared to Saturday.

MARINE

The region will be between high pressure to the south, and frontal zone just to the north through the middle of next week. Southwest flow will continue over the waters, as well as afternoon and evening strong to isolated severe thunderstorm potential over the next several days. Erratic outflow winds may affect area waters at times.

Rip Currents:

Surf heights of less than 2 feet at the northeast FL beaches on Sunday and early next week should also yield a low risk, with a similar low risk likely at southeast GA beaches.

FIRE WEATHER

- Areas Of High Dispersions Today And Tuesday North Of I-10

Drier than normal conditions are forecast through this afternoon before rain chances begin to increase Sunday and into early next week as a frontal boundary approaches from the north. Southwesterly surface winds continue through early next week, with areas of high afternoon dispersion along and north of I-10. Despite drier air in place, minRH will remain just above critical values, in the 30 to 40% range away from the coast this afternoon, but will return to more seasonable MinRh values of 40 to 50% Sunday into next week. Heavy rain potential Sunday through Tuesday due to expected numerous showers and storms each afternoon and evening.

Fog Potential and other remarks: Significant fog potential is not expected. Erratic wind gusts possible in and near thunderstorms, and at times, at a distance due to outflows.

CLIMATE

Daily record high temperatures at our designated climate sites for Sunday, July 12th:

July 12th: KJAX: 102/1879 KGNV: 99/1902 KAMG: 102/1966 KCRG: 99/2015

PRELIMINARY POINT TEMPS/POPS

AMG 76 96 73 92 / 10 30 40 80 SSI 78 96 76 93 / 30 30 20 80 JAX 76 96 75 94 / 40 50 20 80 SGJ 76 94 76 94 / 10 50 20 80 GNV 74 94 74 93 / 20 60 40 70 OCF 75 93 75 94 / 40 60 30 50

JAX WATCHES/WARNINGS/ADVISORIES

FL...Heat Advisory from 11 AM to 7 PM EDT Sunday for FLZ024-038-124- 125-132-137-138-225-232-233-237-325-333-425-433-533-633. GA...Heat Advisory from 11 AM to 7 PM EDT Sunday for GAZ153-154-165- 166. MARINE...None.