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

- Scattered to Numerous Showers and Isolated Thunderstorms Today. Heavy Downpours Possible Along the Interstate 95 Corridor through Thursday

- Strengthening Onshore Winds & Increasing Marine Hazards through Sat. High Risk for Rip Currents and Increasingly Rough Surf at All Area Beaches. Frequent Wind Gusts of 35-45 mph Possible at Coastal Locations on Thursday. Small Craft Advisories through at least Friday Night for All Atlantic Coastal Waters. High Surf Advisories Possible Along the Northeast FL Coast from Thurs - Sat. Minor Coastal Flooding Around Times of High Tide from Thursday Evening. Minor Tidal Flooding Around Times of High Tide within the St. Johns River Basin

UPDATE

No major updates to the expected trends this afternoon. There were a few key adjustments this morning and to rain chances today. Those included cooling expected high temperatures for portions of southeast GA this afternoon (now lower 80s) due to the frontal passage and thick, overcast stratus and expanding rain chances farther inland this afternoon and overnight tonight with the strong northeasterly steering flow pushing showers into the western areas of the coastal counties.

Those strong onshore winds are expected to push up tidal levels through Thursday with potential for minor coastal flooding along the Atlantic coast and within the upper portions of the St Johns, possible the middle St Johns by Friday due to a weak reverse flow.

NEAR TERM /THROUGH TONIGHT/

Main Highlights through Tonight:

- Isolated Thunderstorms this Afternoon, with Locally Heavy Rainfall

- Strengthening Onshore Flow and Beach Hazards Today & Tonight

Low pressure will organize and strengthen east oft he Carolinas today and tonight. As this occurs, an upper trough digs into the southeast states tonight, pushing the backdoor front to our northeast southward through the region and into Central Florida by Thursday Morning with much stronger high pressure building down the southeast coastline accordingly.

The result will be a stronger northeasterly onshore flow building across our area today, with numerous showers and isolated t'storms pushing onshore throughout the day with heavy downpours at times. Most rainfall will be found closer to the coast, though chances for showers will expand further inland throughout the day, especially with a little bit of diurnal enhancement inland. Despite a bit of enhancement, much drier air aloft should limit most t'storm coverage today, though a few isolated storms will be possible which could produce some gusts a bit stronger than the gradient flow.

Overall, drier and cooler conditions will be present over southeast Georgia, especially inland GA. While the strongest conditions and most hazardous beach/marine conditions will generally occur after the near term forecast period, winds build to the 10-20 mph range with gusts as high as 25-30 mph, which will return a high rip current risk to all area beaches today. The developing maritime flow will nudge high temps down a few degrees overall, though today will still be a transition day of sorts, and therefore mid to upper 80s will remain common, though a few readings up to 90 will be possible inland.

The northeasterly surge will build further tonight behind the front as high pressure ridging pushes southward, especially towards the coast. Winds will remain elevated area-wide overnight to prevent any fog, though periods of coastal showers will continue through the overnight hours tonight where onshore winds increase to near or stronger levels later in the night after a slight lull during about the first half of the night. Low temps will remain mild in the low 70s over northeast FL and the coast, though mid to upper 60s will be expected across inland GA as some cooler and drier air starts to filter in.

AVIATION /12Z WEDNESDAY THROUGH 12Z THURSDAY/

A cold front will bring gusty northeasterly winds, scattered to numerous coastal showers, isolated thunderstorms, and a prolonged period of low stratus. A large area of inland low stratus across southeast GA is pushing south toward KGNV and will arrive with LIFR ceilings around 1230z followed by steady improvement to MVFR through 14-15z. A low stratus deck is expected to progress southward along the coast, reaching KSSI around 15z and then the Jacksonville Metro terminals around 17z with ceilings at MVFR to low VFR (2-3 kft). With the cloud cover, a wave of heavy showers may bring brief visibility impacts to terminals along the I-95 corridor. Gusty northeasterly winds will develop through 18z with gusts up to 25 knots this afternoon. Anticipate winds to remain gusty through the evening before tapering off after midnight, except at the coast where gusts will likely persist along with MVFR stratus.

MARINE

Low pressure will strengthen well to the northeast of the region through the end of the week, tracking further to the north of the area through the weekend. High pressure will build down the eastern US coastal states Wednesday causing a backdoor cold front to sweep southward. The gradient between the high, and the front trailing from the low to the northeast, will result in enhanced northeasterly winds and waves beginning later today and lasting through at least Friday. A period of Gale conditions will be possible Thursday into Thursday night. These conditions ease this weekend as high pressure weakens and the aforementioned low pulls further away from the area.

Rip Currents: Rip current risk will increase from north to south today and into Thursday thanks to a northeasterly wind surge, with a high risk expected at all beaches starting today. High risk will persist through at least Friday, and remain elevated through the upcoming weekend as rough and mostly short period seas persist.

FIRE WEATHER

- Elevated Nighttime Dispersions At Coastal Locations Tonight ELEVATED NIGHTTIME DISPERSIONS ALONG THE I-95 CORRIDOR AND - Coastal Locations On Thursday Night

Scattered to numerous showers and thunderstorms are expected to develop early this morning at coastal locations, with activity then spreading south and westward across most of northeast and north central FL by this afternoon. Shower activity will then shift to the Interstate 95 corridor tonight through Thursday evening before a drier air mass overspreads our entire area from Friday through Monday. This drier air mass will drop minimum humidity values to near critical thresholds across inland portions of southeast Georgia by Sunday afternoon.

Northeasterly transport winds will gradually strengthen from north to south today today, with breezy surface winds developing along the I-95 corridor during the mid to late morning hours and then spreading inland this afternoon. These strengthening winds will create fair to good daytime dispersion values. North-northeasterly surface and transport winds will remain breezy at coastal locations tonight, creating elevated nighttime dispersion values. North- northeasterly surface and transport winds will continue to strengthen on Thursday and Thursday night along the I-95, with breezy conditions redeveloping at inland locations by mid-morning Abundant lower cloud cover will keep daytime dispersion values in the fair to good range despite breezy to windy conditions. Elevated nighttime dispersion values are forecast to continue along the I-95 corridor on Thursday night due to breezy surface speeds. Breezy northerly surface and transport winds and decreasing cloud cover on Friday at inland locations will create good daytime dispersion values area-wide.

Fog Potential...Significant fog formation is not expected during the next several days.

TIDES/COASTAL FLOODING

Astronomical tides will rise through the weekend due to the upcoming Full "Harvest" Moon that occurs on Saturday. A northeast wind surge will overspread coastal locations through Thursday will combine with the increasing astronomical tides to create minor coastal flooding along the Atlantic coast from Thursday evening through at least Saturday. Minor flooding will be possible along the Atlantic coast beginning with the evening high tide on Thursday, where water levels of 1.5 - 2.5 feet above Mean Higher High Water (MHHW) are preliminarily forecast, which will create mostly minor, nuisance type flood impacts. Minor flooding will then expand to the St. Johns River basin beginning on Friday and are expected around times of high tide through the weekend and into next week, as rising astronomical tides beyond the date of the Full Moon keep water levels elevated, generally at 1-2 feet above MHHW during each tide cycle for most locations within the basin.

PRELIMINARY POINT TEMPS/POPS

AMG 88 68 79 61 / 20 10 0 0 SSI 85 71 79 64 / 40 30 20 10 JAX 86 72 80 65 / 50 20 30 20 SGJ 85 74 81 71 / 60 40 60 30 GNV 89 71 85 66 / 40 10 20 0 OCF 91 73 86 68 / 40 20 20 0

JAX WATCHES/WARNINGS/ADVISORIES

FL...High Risk for Rip Currents through late Saturday night for FLZ124- 125-138-233-333. GA...High Risk for Rip Currents through late Saturday night for GAZ154- 166. MARINE...Small Craft Advisory until 8 PM EDT Friday for AMZ450-470. Small Craft Advisory from 6 PM this evening to 2 AM EDT Saturday for AMZ452-454-472-474.