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 Strong Thunderstorms with Locally Heavy Rainfall Possible through Early this Evening, Mainly for Inland Northeast and North Central FL.

- Areas of Locally Dense Fog Possible Across Inland Southeast GA Late Tonight and Early Thursday Morning, Mostly for Locations North of Waycross.

- Widely Scattered Afternoon and Evening Thunderstorms on Thursday.

- Increasing Rain and Thunderstorm Chances Friday through Next Week. Isolated Strong Thunderstorms & Heavy Downpours Friday and Saturday. Locally Heavy Rainfall Potential Sunday through Next Week.

- Increasing Coastal and Marine Impacts Expected Next Week.

- Moderate Risk of Rip Currents Continues at All Area Beaches.

NEAR TERM /THROUGH TONIGHT/

Main Highlights:

- Isolated Strong Thunderstorms with Locally Heavy Rainfall Possible through Early this Evening, Mainly for Inland Northeast and North Central FL.

- Areas of Locally Dense Fog Possible Across Inland Southeast GA Late Tonight and Early Thursday Morning, Mostly for Locations North of Waycross.

Afternoon surface analysis depicts a decaying frontal boundary that stretches along the Interstate 10 corridor. Meanwhile, high pressure (1023 millibars) was centered over VA and NC in the wake of this boundary. Aloft...a narrow trough extends from the eastern Gulf through our region, as ridges were centered to the east of the Bahamas and over the lower Mississippi and Tennessee Valleys. Otherwise, a powerful trough in the southern branch of the jet stream was progressing slowly across the Four Corners region in the Desert Southwest. Latest GOES-East derived Total Precipitable Water imagery indicates that deeper moisture prevails to the south of the aforementioned frontal boundary, where PWATs were generally in the 1.5 - 1.75 inches, while values north of I-10 were mostly in the 1.25 - 1.5 inch range. Widely scattered showers and thunderstorms were developing within an enhanced cumulus field located along and south of the stalled boundary, with a slow, general westward movement to this activity. Outside of developing thunderstorm activity, temperatures at 19Z were generally in the 85-90 degree range inland and the low to mid 80s at coastal locations, where onshore winds were becoming breezy. Dewpoints ranged from the low and mid 60s to the north of the frontal boundary across inland southeast GA and the northern Suwannee Valley, while upper 60s and lower 70s prevailed elsewhere.

Widely scattered showers and a few thunderstorms will continue through around sunset for locations along and south of the Interstate 10 corridor, where deeper moisture resides around a slowly dissipating frontal boundary. Relatively cold temperatures aloft and colliding mesoscale boundaries may cause a few storms to "pulse" and become strong through around sunset, mainly for locations along the U.S. Highway 301 corridor in northeast and north central FL. Stronger storms this afternoon and early this evening could contain brief wind gusts of 35-45 mph, frequent lightning strikes, and torrential downpours, with the slow movement of these downpours potentially creating some threat for localized flooding, especially if downpours were to persist over more urban locations such as Gainesville, Lake City, Palatka, or Ocala. Activity should conclude early this evening.

High pressure centered along the Carolina coast late this afternoon will move offshore overnight, with low level southeasterly flow potentially bringing a few showers developing over the Atlantic waters overnight onshore towards sunrise, mainly for locations from around St. Augustine southward. Otherwise, gradually increasing moisture levels and decoupling winds could produce another round of dense fog for inland locations in southeast GA, mainly for areas north of Waycross. Lows tonight will range from the upper 60s across inland southeast GA and northeast FL to the lower 70s across north central FL, while a light onshore breeze keeps coastal lows mostly in the mid 70s.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/

Main Highlights:

- Return to summer like pattern: Scattered thunderstorms Thursday and Friday, with highs in the upper 80s to low 90s. Chances for showers and storms will increase on Thursday and Friday as prevailing flow shifts to become more southerly and drier air is replaced with moist maritime air guided via high pressure over the Atlantic, raising PWAT values up to about 2.3 to 2.45 inches by the end of the period. Convection is expected to be heaviest over north central Florida on Thursday and then spreading to cover most of northeast Florida and extending into southeast Georgia on Friday. Daily high temperatures for the end of the week will rise into the lower 90s over inland areas and in the mid to upper 80s for coastal counties. Overnight low temperatures will drop down into the upper 60s and lower 70s for inland areas and in the mid 70s for areas along the coast and near the St Johns River.

LONG TERM /SATURDAY THROUGH WEDNESDAY/

Main Highlights This Period:

- Above normal thunderstorm chances with strong to marginally severe storms possible Sunday.

- Strong northeasterly winds developing Tuesday onward.

Prevailing flow will shift about to become more out of the southwest as flow becomes situated between high pressure riding extending over the southern Florida peninsula from out of the east and an advancing cold front pressing in from out of the northwest, resulting in more widespread showers and thunderstorms for southeast Georgia and northeast Florida. A significant amount of rainfall is anticipated through this period with a potential for 2 to 3 inches of rain over portions of northeast Florida and 1 to 2 inches for parts of southeast Georgia. Temperatures will experience a cooling trend through the end of the weekend and into the beginning of next week, with temps expected to drop down to be below the seasonal average by Monday and Tuesday.

AVIATION /18Z WEDNESDAY THROUGH 18Z THURSDAY/

Showers and thunderstorms located just west of the JAX and VQQ terminals early this afternoon are expected to move slowly westward, ending vicinity thunderstorm coverage at these terminals towards 20Z- 21Z. Showers developing near the GNV should increase in coverage and intensity after 20Z, and a PROB30 group for thunderstorms with brief surface wind gusts up to 25 knots and MVFR visibilities during heavier downpours was maintained at GNV through around 00Z this evening. VFR conditions should then prevail after 00Z through at least 03Z at the regional terminals. MVFR to IFR visibilities will then develop at VQQ towards 05Z, with periods of LIFR conditions expected through around 11Z. VFR conditions should then prevail by 12Z, with a few coastal showers potentially impacting SGJ towards 13Z. Confidence was too low to indicate anything other than vicinity showers at SGJ at this time on Thursday morning. Northeast to east surface winds sustained at 10-15 knots outside of thunderstorm activity will shift to east or southeasterly after 22Z, with sustained speeds diminishing to around 5 knots overnight at the SSI and SGJ coastal terminals and less than 5 knots inland. East to southeasterly winds will then increase to 5-10 knots by 15Z Thursday at the regional terminals.

MARINE

High pressure centered over the Carolinas will shift eastward and offshore of the Outer Banks later this afternoon. Meanwhile, a stalled frontal boundary over the northeast Florida waters will gradually dissipate through tonight, with widely scattered showers and a few embedded thunderstorms possible throughout our local waters today, followed by coverage shifting south of the waters adjacent to St. Augustine tonight. Prevailing easterly winds today will shift to southeasterly tonight, with coverage of showers and thunderstorms expected to slowly increase on Thursday and Thursday night. Showers and thunderstorms will then continue to increase on Friday and Saturday, and a frontal boundary settling over the southeastern states late this weekend and early next week will produce waves of widespread showers and thunderstorms throughout our local waters. Strong high pressure building over the Great Lakes and Mid-Atlantic states in the wake of this frontal boundary early next week will wedge down the southeastern seaboard beginning on Tuesday, creating strengthening northeasterly winds and building seas through late next week.

Rip Currents: A combination of long period east swells near 1-2 ft, onshore flow, and prior surf conditions suggest a low-end moderate risk of rip currents through Thursday.

FIRE WEATHER

Moisture will return to the area, with chances of showers and storms increasing this week, the highest coverage will be over north central Florida. By the end of the week, coverage expands but highest thunderstorm chances remain focused across northeast Florida. Overall, dispersion will be fair to good this week, with potentially for areas of low afternoon dispersion this weekend.

Fog Potential...Patchy fog over inland southeast Georgia and portions of northeast Florida early Wednesday morning, and across inland southeast Georgia Thursday morning.

EQUIPMENT

KVAX radar will remain down until further notice. Parts are on order.

PRELIMINARY POINT TEMPS/POPS

AMG 68 90 70 91 / 0 10 0 70 SSI 75 85 76 86 / 10 10 10 40 JAX 70 87 73 88 / 10 30 10 70 SGJ 75 86 76 87 / 20 30 20 60 GNV 70 90 72 90 / 20 60 20 80 OCF 70 91 73 91 / 30 70 30 80

JAX WATCHES/WARNINGS/ADVISORIES

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