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

- Isolated Thunderstorms this Afternoon for Locations South of I-10

- Widely Scattered Afternoon & Evening Thunderstorms on Saturday

- Scattered to Numerous Mainly Afternoon & Evening TStorms from. Isolated Strong Storms and Locally Heavy Rainfall Possible

- Moderate Rip Current Risk at All Area Beaches

NEAR TERM /THROUGH TONIGHT/

Main Highlights through Tonight:

- Moderate Rip Current Risk at All Area Beaches

- Isolated Thunderstorms Possible this Afternoon, Mainly for Locations South of Interstate 10

Overnight surface analysis depicts slowly weakening high pressure (1024 millibars) situated over the southeastern states. Meanwhile, coastal troughing was positioned over the near shore waters adjacent to northeast FL. Otherwise, a cold front was pushing southward from the Mid-Atlantic states and the Ohio Valley, with stronger high pressure (1031 millibars) building over the Upper Midwest and the Great Lakes states in the wake of this frontal boundary. Aloft...a Tropical Upper Tropospheric Trough (TUTT) was spinning slowly westward across the Gulf Stream waters adjacent to northeast and east central FL, while "Heat Wave ridging was centered over northeast TX, the Ozarks, and the lower Mississippi Valley. Latest GOES-East derived Total Precipitable Water imagery indicates that our air mass is gradually moistening from east to west, with PWAT values now in the 1.8 - 2 inch range across portions of north central FL, ranging to values around or just below 1.5 inches across portions of inland southeast GA and western portions of the Suwannee Valley. Coastal troughing and gradually cooling temperatures aloft were generating isolated showers over the Atlantic waters that were occasionally moving onshore, mainly for locations south of the I-10 corridor, with a few showers surviving their inland trek across north central FL, where deeper moisture was now in place. Fair skies prevail across most of southeast GA and the Suwannee Valley, where temperatures and dewpoints have mostly fallen to the upper 60s as of 07Z. Breezy onshore winds were keeping temperatures in the upper 70s to around 80 at coastal locations, with temperatures and dewpoints otherwise generally in the lower 70s across the rest of our area.

The TUTT feature situated just off the northeast and east central FL coast will migrate slowly southwestward today and tonight, traversing north central FL and the I-4 corridor this afternoon and evening, then emerging over the far eastern Gulf just west of Tampa Bay and the FL Nature coast by sunrise on Saturday. Meanwhile, high pressure over the southeastern states will weaken today as a cold front enters the Tennessee Valley and the Carolinas overnight tonight. Otherwise, weak coastal troughing will remain in place over the near shore waters adjacent to northeast FL. This evolution of the weather pattern will keep deeper moisture in place for locations south of Interstate 10, with coastal troughing and onshore winds will develop isolated to widely scattered showers and a few embedded thunderstorms over the Atlantic waters that may occasionally push onshore through late this afternoon. Ridging positioned to the west of our region will continue to extend its axis eastward across the southeastern states, providing a slightly drier and more subsident air mass for southeast GA, extending southward to the I-10 corridor. Highs at these locations will soar to the lower and possibly middle 90s, but dewpoints will mix down to the 65-70 range this afternoon, keeping peak heat index values in the upper 90s to around 100. Breezy onshore winds will keep coastal highs in the mid to upper 80s today.

Coastal troughing will weaken tonight, and our local pressure gradient will continue to gradually loosen as high pressure weakens over our area. Shower chances should diminish further at coastal locations as onshore winds diminish, where lows will fall to the mid and upper 70s. Inland temperatures should fall to the upper 60s and lower 70s.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/

Main Highlights This Period:

- Scattered to possibly numerous showers and storms This Weekend

Surface ridging over the eastern seaboard weakens as a mid/upper level Low over the FL peninsula gradually shifts into the eastern Gulf this weekend. Convective coverage increases this weekend with an increase in low level moisture coming in from the Atlantic combined with diurnal instability and enhanced by passing shortwaves aloft. Isolated to widely scattered showers and storms develop along the Atlantic sea breeze as it shifts well inland and eventually merges with the Gulf sea breeze along the I-75 corridor late Saturday afternoon into evening. Coverage becomes more numerous on Sunday in the moist and unstable ESE deep layer flow. A few stronger storms could produce gusty winds and heavy downpours.

Onshore winds will continue the same spread of daytime temperatures with relatively cooler highs along the coasts in the mid to upper 80s, with lower 90s further inland. Overnight lows will mainly be in the 70s.

LONG TERM /MONDAY THROUGH THURSDAY/

Main Highlights This Period:

- Daily chances for showers and thunderstorms with locally heavy rainfall possible

The closed mid/upper Low over the eastern Gulf will meander and dissipate by mid-week as weak ridging continues at the surface. Scattered to numerous diurnally driven showers and storms develop into mid-week, with moist air (PWATs ~2") continuing to filter into the area from the Atlantic. A cold front dips southward into the SE US Tuesday and then shifts across the region Wednesday into Thursday. High pressure and slightly drier air builds in behind the front lowering coverage to be more scattered.

Daytime high temperatures will be in the mid 80s to lower 90s with overnight lows in the 70s.

AVIATION /12Z FRIDAY THROUGH 12Z SATURDAY/

Coastal showers continue and may graze or pass over NE FL terminals today. Predominant conditions will be VFR with multilayered clouds and lowest bases around 3kft. Northeasterly winds prevail at all sites, increasing to 10-15 knots by 16z. VFR conditions hold tonight but coastal airfields may experience brief MVFR ceilings as bouts of stratocumulus push in from the Atlantic.

MARINE

High pressure situated over the southeastern states will gradually weaken today, with a weak coastal trough positioned over the northeast Florida waters developing scattered showers and possibly an embedded thunderstorm through late this afternoon, mostly for the waters from St. Augustine southward. Winds and seas should remain below Caution levels during the next several days throughout our local waters, and surface trough and disturbance aloft crossing the Florida peninsula on Saturday will emerge over the eastern Gulf on Sunday and Monday. Showers and thunderstorms are expected to increase beginning late Saturday night, with activity likely continuing through at least early next week. A stronger high pressure center may attempt to wedge down the southeastern seaboard later next week, potentially resulting in another round of stronger northeasterly winds across our local waters.

Rip Currents: Breezy onshore winds will keep breakers in the 3-4 foot range at the northeast FL beaches today, while values subside to the 2-3 foot range at the southeast GA beaches. These conditions will generally yield a higher end moderate risk at all area beaches. Northeasterly winds will only gradually subside this weekend and early next week, maintaining a moderate risk at area beaches.

FIRE WEATHER

Northeast to east winds will continue today but not as breezy as previous days. Fair to good daytime dispersions prevail through Saturday. Slightly drier air over portions of the region will keep rain chances low today, with only rounds of isolated showers moving onshore along the coast and into north-central Florida. Shower and storm chances increase this weekend as the Atlantic sea breeze shifts well inland each afternoon.

Fog Potential...No significant fog expected. However, patchy fog is possible for inland areas in the early morning hours this weekend.

PRELIMINARY POINT TEMPS/POPS

AMG 93 70 92 71 / 10 10 30 20 SSI 88 75 88 76 / 0 10 10 20 JAX 89 70 90 73 / 10 10 10 10 SGJ 87 76 88 75 / 20 10 20 30 GNV 91 70 91 71 / 20 0 30 0 OCF 92 70 91 70 / 20 0 30 0

JAX WATCHES/WARNINGS/ADVISORIES

FL...None. GA...None. MARINE...None.