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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 Afternoon and Evening Thunderstorm Potential through Friday. Main Impact Area this Afternoon and Evening: Suwannee Valley and Inland Southeast GA.

- Dense Fog Possible Early on Thursday and Friday Mornings.

- High Risk for Rip Currents at Northeast FL Beaches through Tonight. Moderate Risk at the Southeast GA Beaches. Moderate Risk at All Area Beaches from Thursday through the Weekend.

- Tidal Flooding Continues within Portions of the St. Johns River Basin. Minor Flooding During Times of High Tide in Putnam & Western Flagler Counties through at least Thursday Night.

NEAR TERM /THROUGH TONIGHT/

Main Highlights:

- Isolated Thunderstorms Possible Late this Afternoon and Evening, Mainly for Locations West of I-75 and U.S. Highway 301.

- Locally Dense Fog Possible Towards Sunrise on Thursday at Inland Locations.

- Minor Tidal Flooding Continues Within Portions of the St. Johns River Basin.

Afternoon surface analysis depicts a lengthy cold front stretching from the Great Lakes southward through the Tennessee and Lower Mississippi Valleys, with a pre-frontal trough extending from Apalachee Bay northward across eastern portions of the FL panhandle and through the Chattahoochee Valley in the Deep South. Aloft...ridging aloft remains in place along the U.S. eastern seaboard, with this feature deflecting a potent shortwave trough northeastward through the Upper Midwest, while another shortwave was moving eastward across the Intermountain West. Latest GOES-East derived Total Precipitable Water imagery indicates that an unseasonably moist air mass prevails across our region, with PWATs generally ranging from 1.6 to 1.9 inches across most of our area. Deeper moisture is located just along and south of the Interstate 4 corridor in the FL peninsula. Strengthening isentropic lift ahead of the prefrontal trough was generating isolated showers across our area that were moving slowly northward, mainly for locations along and west of U.S. Highway 301. Unseasonably warm and humid conditions otherwise continue across our area, with temperatures at 19Z in the low and mid 80s, with dewpoints remaining in the upper 60s and lower 70s.

Ridging aloft along the southeastern seaboard will continue to deflect a potent shortwave trough east-northeastward from the Upper Midwest across the Great Lakes states through tonight. This weather pattern will tend to slow the forward progress of an associated surface cold front and pre-frontal trough through tonight, with a low level jet remaining positioned to the northwest of our region across central and northern portions of AL and GA, extending into the Tennessee and Ohio Valleys. Ridging aloft over our area has kept a more stable air mass in place, and showers developing in the humid air mass have generally been transient in nature so far this afternoon. However, enough moisture and potential interaction of convective outflows with other mesoscale boundaries such as the Gulf sea breeze and the inland moving Atlantic sea breeze should result in a gradual increase in shower coverage this afternoon, and perhaps a few embedded thunderstorms through early this evening, mainly for locations along the I-75 corridor in the Suwannee Valley and north central FL as well as locations west of the U.S. Highway 301 corridor in interior southeast GA.

Shower activity should wane towards midnight tonight, with a loosening pressure gradient and moist air mass fostering the development of low stratus cloud cover towards sunrise. Mid and high altitude cloud cover should move eastward across our area overnight and offshore towards sunrise, potentially resulting in widespread fog formation that could be locally dense early on Thursday morning. Lows tonight will only fall to the mid and upper 60s throughout our region.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/

Main Highlights This Period:

- Dense Fog Possible Early on Thursday and Friday Mornings.

A cold front will push towards the region on Thursday, pushing through on Friday Night. With the approaching frontal boundary, a southwesterly wind shift for much of the area will allow for Gulf moisture to be brought inland, which may allow for some showers to develop during the afternoon hours on Thursday along the sea breezes. By the evening hours, could have some light showers along far inland SE GA. With near calm winds, could bring some patchy to areas of fog during the overnight hours into Friday across inland locations, mainly for NE FL locations. By Friday, southwest winds across the area will keep the onshore flow pinned along the coast with scattered chances of showers during the afternoon hours.

Daytime highs will be in the low to mid 80s Thursday and Friday afternoon. Overnight lows will be around the mid 60s inland and mid to upper 60s along the coast Thursday Night. Behind the front, cooler temperatures will bring Lows in the mid 50s across SE GA. Lows across NE FL will still sit in the mid 60s as the front will still be working its way southward.

LONG TERM /SATURDAY THROUGH WEDNESDAY/

Main Highlights This Period:

- Cooler and Drier Conditions Expected this Weekend.

After the front's passage, drier air filters into the area which will keep conditions on the dry side for the upcoming weekend and into the start of next week. Monday Night, both the GFS and Euro show different evolutions of a upper level trough. The GFS shows the trough digging further south and pushing across the local region by midweek, setting up the potential for a wet pattern developing during the overnight hours into Tuesday. Whereas the Euro depicts a less aggressive pattern, which would keep dry conditions into midweek.

Below normal temperatures will across the area behind the front. Daytime Highs in the upper 70s to lower 80s on Saturday will cool into the lower 70s over the weekend and into next week. Overnight Lows in the lower 50s across the area on Saturday will dip to the mid 40s by Monday for SE GA and to the lower 50s across NE FL.

AVIATION /18Z WEDNESDAY THROUGH 18Z THURSDAY/

Scattered showers developing near the GNV and VQQ terminals could create brief periods of MVFR visibilities through around 06Z tonight. Confidence in timing and intensity remains too low to indicate anything other than vicinity coverage at this time. A PROB30 group may be added for MVFR conditions later this afternoon as activity potentially increases in coverage and intensity at the GNV terminal. There also remains a low probability for an isolated thunderstorm to develop west of GNV towards 20Z, but confidence was too low to indicate vicinity thunderstorms at this time. Otherwise, VFR conditions will prevail at the regional terminals through at least 07Z. Low stratus ceilings are expected to overspread the terminals during the predawn and early morning hours on Thursday, with low MVFR conditions indicated, except at VQQ, where IFR to LIFR conditions are expected to develop towards 08Z. Ceilings are expected to lift by 14Z, with VFR conditions then prevailing by 15Z Thursday. Southeasterly surface winds sustained at 10-15 knots and gusty will tend to shift to easterly while gradually weakening to 5-10 knots towards 21Z. Light southerly surface winds will then develop towards 13Z at the regional terminals, followed by the Atlantic sea breeze shifting surface winds to east-southeasterly around 10 knots at the SSI and SGJ coastal terminals by 17Z Thursday.`

MARINE

Elevated seas will continue across the offshore waters adjacent to northeast Florida through early this evening. Meanwhile, a cold front entering the southeastern states tonight will slow its forward speed, with prevailing winds shifting to southerly on Thursday and then southwesterly on Friday and Friday night. Scattered showers and isolated thunderstorms may impact the waters on Friday afternoon and evening ahead of this approaching front, which will cross our local waters before sunrise on Saturday. Winds will shift to northwesterly with increasing speeds after midnight on Friday night, followed by winds shifting to northerly and then northeasterly in the wake of this frontal passage on Saturday afternoon and evening. High pressure will gradually build into the southeastern states on Sunday and Monday, creating breezy northeasterly winds and gradually building seas across our local waters.

Rip Currents / High Surf: A high risk of rip currents continues this afternoon at the northeast FL beaches, while a higher end moderate risk is expected at the southeast GA beaches. Surf heights are only gradually decreasing, with 3-5 foot breakers expected to continue through Thursday at the northeast FL beaches. Onshore winds will weaken on Thursday and will shift to an offshore direction by Friday. However, a lingering easterly ocean swell will still yield a moderate risk at all area beaches from Thursday through the upcoming weekend.

FIRE WEATHER

- Low Dispersions South Of The I-10 Corridor on Thursday Afternoon.

Winds will continue to decrease through the end of the week as a cold front approaches. Easterly to southeasterly winds continue during the overnight hours into Thursday. As winds ease up Thursday, dispersions will fall to poor or low levels, especially at the coast and locations south of the I-10 corridor. Winds begin to shift to become southwesterly ahead of the a weak and mostly dry cold front, which will push across Friday night, ushering in a drier and cooler airmass over the weekend and into early next week.

FOG POTENTIAL AND OTHER WEATHER REMARKS: Areas to widespread fog will be possible during the predawn and early morning hours on Thursday and Friday across the area.

TIDES/COASTAL FLOODING

Water levels within most of the St. Johns River basin continue to gradually decline with each successive high tide cycle, with gauges now reporting peak levels mostly in the action stage (below minor flooding) from around Racy Point northward. We have thus discontinued the Coastal Flood Advisory for all but Putnam and western Flagler Counties, where tides continue to reach 1.5 to 2 feet above normally dry ground during times of high tide (minor flooding). Recent heavy rainfall over central FL may allow elevated water levels to linger for locations along the St. Johns River and its tributaries near Lake George and Crescent Lake during the next several days as the floodwater drains northward.

PRELIMINARY POINT TEMPS/POPS

AMG 66 83 66 81 / 40 10 20 20 SSI 68 79 66 80 / 10 20 10 30 JAX 67 85 66 84 / 20 10 10 20 SGJ 69 82 67 83 / 10 10 10 20 GNV 67 85 67 84 / 30 20 20 10 OCF 67 86 68 85 / 20 10 10 10

JAX WATCHES/WARNINGS/ADVISORIES

FL...Coastal Flood Advisory until 4 AM EST Friday for FLZ038-137. High Risk for Rip Currents through late tonight for FLZ124-125-138- 233-333. GA...None. MARINE...None.