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

- Hot and humid with Heat Indices of 108-110F this afternoon

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

NEAR TERM /THROUGH TONIGHT/

Main Highlights For Today and Tonight:

- Heat Advisory for portions of NE FL/SE GA from 11am-7pm, mainly along the I-10 and I-95 corridors for Heat Indices of 108-110F

- Scattered to Numerous Showers and Thunderstorms with locally heavy rainfall potential, mostly across Northeast Florida

Amplified Eastern US trough in the mid levels has pushed the frontal boundary all the way into SE GA at the surface with drier air filtering aloft and models have been way too aggressive with overall rainfall chances during the early morning hours today, with only a few isolated showers/storms expected. The frontal boundary at the surface will sag all the way into NE FL and along the I-10 corridor by the afternoon hours. For now still believe the models may be too aggressive with rainfall chances this morning, with most activity expected to kick off by the mid-late afternoon hours along the Gulf Coast sea breeze and I-75 corridor of inland NE FL as the SW steering flow will keep the East Coast sea breeze pinned close to the Atlantic Coast this afternoon. Was hoping to be all done with Heat Advisory headlines, but the pinned East Coast sea breeze and proximity of the frontal boundary will lead to above normal dew point temps well into the mid/upper 70s across NE FL and coastal SE GA, while they mix out into the lower 70s across inland SE GA. These dew point temps combined with Max temps still reaching into the lower to middle 90s for most areas, and still even some upper 90s across inland SE GA will still support Heat Indices of 108-110F by the early afternoon across portions of SE GA and portions of NE FL, mainly along the I-95 and I-10 corridors, and have posted a marginal Heat Advisory for Today, while areas across Alachua, Gilchrist and Marion Counties should have high enough cloud cover and rainfall chances to have peak heat indices around 105F, along with portions of inland SE GA where lower dew point temps closer to 70F will hold Heat indices closer to 105F there as well. Afternoon/Evening convection along and to the south of the stalled frontal boundary will be set up for isolated strong/severe storms once again with damaging winds of 40-60 mph still possible in wet microburst activity and slower storm motion and training of storms off the NE Gulf and interaction with the stalled frontal boundary along the I- 10 corridor will lead to localized flood threat from the heavy downpours with isolated 2-4 inch rainfall amounts in the more intense storms. Ongoing drought conditions across most of NE FL and lack of recent rainfall should prevent the need for any flood watch at this time, but will need to be monitored as convection breaks out along the frontal boundary later this afternoon/evening. Storms will continue well into the evening hours as outflows continue to trigger convection pushing northward through SE GA through the late evening hours, with most activity finally coming to an end around midnight. Overnight lows a bit closer to normal in the lower/middle 70s inland and upper 70s along the Atlantic Coast.

SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/

Main Highlights This Period:

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

An overall similar setup to Thursday will be expected Friday, as the diffuse frontal boundary remains nearly stationary just north of our region. Some lingering pockets of drier air/lower PWATs over interior southeast GA will likely limit convective coverage for this area, with the highest chances/coverage of showers and thunderstorms expected to be generally along and south of I-10 and towards the coasts. Overall setup does not look significant with respect to strong to severe potential, however certainly cannot rule out an isolated downburst of up to 40-55mph with the presence of some drier air and the nearby frontal boundary aiding with synoptic lift along with the usual sea breezes. High temps nudge down a bit Friday, generally in the low to mid 90s. Guidance has overall been a bit over done with respect to lingering convection into the overnight hours, though a few showers or an isolated thunderstorm will be possible mainly closer to the Gulf coast Friday Night with just some lingering debris clouds otherwise, with lows in the low to mid 70s common.

Saturday, the above mentioned front lifts a bit further north, as another boundary and upper level trough swings southeastward towards the southeast states through Saturday Night. The upper level support slows down and weakens approaching our region which is expected for a summer pattern. However, major models do agree regarding a "surge" of layer moisture in addition to some added divergence and some lingering upper energy, and therefore expecting more widespread convective activity Saturday as PWATs surge to the 2-2.3 inch range. Strong to severe potential looks to bump up slightly, in addition to the flooding potential with some cells thanks to the very high moisture levels. Temperatures will top out mainly in the low 90s once again and into the low to mid 70s Saturday Night. A few showers or an isolated t'storm could once again linger into the overnight hours, especially closer to the Gulf Coast west of I-75 once again.

LONG TERM /SUNDAY THROUGH WEDNESDAY/

Main Highlights This Period:

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

An active pattern looks to persist to end the weekend and into the next work week as a weak frontal zone remains just north of the region and an upper level low to the west/northwest continues to feed tropical Gulf moisture across the area. Convective coverage overall looks to remain numerous to widespread each day. No specific day/setup sticks out significantly regarding strong to severe t'storm potential, but a few strong downbursts will be possible each day, in addition to a continued heavy rain/flooding threat with the ample layer moisture. Temperatures trend overall near to slightly below normal for much of the long term as a result of the more active pattern.

AVIATION /06Z THURSDAY THROUGH 06Z FRIDAY/

Convection has ended at all TAF sites early this morning, with VFR conds developing and expect to continue, except for some patchy MVFR fog at VQQ. Rainfall chances increase again this afternoon in the SW flow and expect to continue TEMPO groups at all NE FL TAF sites and only PROB30 groups at SSI for IFR/MVFR conds in TSRA activity, mainly in the 20-24Z time frame. Expect VFR conds to return after sunset (00Z Friday) with a few lingering showers/stratiform rainfall (VCSH) through the end of the TAF period.

MARINE

A frontal zone will be located near or over the area through Friday, then to the north through the weekend. This will lead to a prevailing offshore flow through early next week, with the local sea breeze pinned near the coast each day.

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

- Heat Advisory in Effect Near I-10 & the Coast Today - Isolated Strong to Severe Storms Possible Rest of the Week

An active pattern will persist today and Friday as a frontal boundary remains nearly stationary just north of the region. Numerous showers and thunderstorms will be expected, especially across northeast FL during this time frame. Despite stronger flow south of the boundary over northeast FL, better mixing over southeast GA will result in good dispersions over most of the area through Friday. MinRH values may drop below 40% today over far interior GA with some drier air, but expected to remain above any critical thresholds. The pattern looks to remain active this weekend as another frontal boundary and abundant moisture approaches the area Saturday and persists into the start of next week.

Fog Potential: Significant fog development is not expected during the next several mornings. As mentioned above, isolated strong to severe thunderstorms are possible through the rest of the week. 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 97 72 95 73 / 20 20 40 20 SSI 93 76 93 77 / 40 30 40 30 JAX 95 74 93 73 / 70 50 50 30 SGJ 93 74 92 74 / 60 50 60 60 GNV 91 74 92 73 / 70 60 60 50 OCF 90 74 91 74 / 80 60 70 60

JAX WATCHES/WARNINGS/ADVISORIES

FL...Heat Advisory from 11 AM this morning to 7 PM EDT this evening for FLZ021-023-024-030-031-038-120-124-125-132-137-138- 220-225-232-233-237-322-325-333-422-425-433-522-533-633. GA...Heat Advisory from 11 AM this morning to 7 PM EDT this evening for GAZ152>154-162-163-165-166-250-264-350-364. MARINE...None.