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

- Minor Tidal Flooding for NE FL Atlantic beachfront and the St. Johns River basin through Tuesday

- Moderate Risk of Rip Currents at local beaches

- Isolated Thunderstorm Activity Returns Mid to Late Week

NEAR TERM /THROUGH TUESDAY/

Main Highlights Today and Tonight:

- Moderate rip current risk at Atlantic beaches

- Minor flooding will continue along the St. Johns River Basin during times of high tide through this evening

A weak stalled frontal boundary remains draped over the FL/GA border providing a moisture gradient with PWATs around 0.8-1.1" north and around 1.2-1.7" south of the boundary. The slight increase in moisture combined with diurnal heating could trigger a brief shower along the Gulf sea breeze as it shifts inland mainly for Marion county. Otherwise, dry conditions prevail today. Highs today will be above seasonable in the the upper 80s to around 90 with mid 80s along the immediate Atlantic coast. Near seasonable lows tonight in the 60s inland to the low 70s along the coast and St Johns river. A slight increase in low level moisture will allow for some shallow, patchy dense fog to develop around sunrise across inland SE GA and NE FL.

SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/

Main Highlights through Tonight:

- Moderating temperatures, and slowly increasing moisture this period

- Scattered showers midweek over North Central FL

The stationary front draped across the local area will begin to clear as its associated Low pressure over the Gulf of Maine shifts further north. High pressure over the Atlantic will begin to shift further north bringing southeasterly winds on Tuesday, then becoming easterly by Wednesday as gusts of around 15 to 20 mph will possible during the afternoon hours along the coast. With the switch to onshore flow, moisture levels will steadily increase during this period, with the highest PWATs over north central FL and coastal locations of NE FL by Wednesday afternoon. There is a chance for some showers and storms on Tuesday, a bit stronger onshore flow on Wednesday, will bring relatively higher chances of showers and storms across north central FL return by the afternoon hours.

Daytime highs during this period will primarily be in the upper 80s to lower 90s on Tuesday. A bit 'cooler' temperatures on Wednesday as the onshore flow increases, with lower to mid 80s along the coast and along the St. Johns River, upper 80s to lower 90s for inland locations west of the I-95 corridor. Overnight hours will have temperatures in the upper 60s across inland locations and the lower 70s along the coast. Some patchy fog will be possible during the overnight hours, primarily for inland locations as near calm winds and clear skies be present.

LONG TERM /THURSDAY THROUGH MONDAY/

Main Highlights This Period (Thursday through Sunday):

- Potential for strong storms with heavy rainfall increases this period

Thursday and Friday, mid/upper level ridging just off the SE US coast remains as a closed mid level shortwave trough over the southern/central plains moves eastward on Thursday and then opens up and merges with a broad northern trough over the Midwest/Great Lakes. This pattern will keep high pressure NE of the area bringing a moist ESE onshore flow to the area as a surface low well to the west moves ENE from northern TX to the Ozarks Plateau through the day Friday. A weak warm front forming along the Gulf coast will extend eastward into the area. This front will become a focus for increasing coverage of showers with numerous shower coverage Friday for much of the area. Warming high temperatures will increase instability and along with the return of a very moist airmass (PWATs over 2.00 inches, over the 90th percentile for early Oct) and lift along the front and inland moving Atlantic seabreeze will support increasing thunderstorm coverage with scattered thunderstorms for much of the area on Friday. Most of the storms will be more of the pulse nature due to weak shear the end of the week over the area. Rainfall amounts Thursday through Friday will be overall a tenth to a quarter of an inch with isolated higher totals around an inch.

Saturday, ridging aloft northeast of the region will extend SSW to the northern Bahamas while strong shortwave trough diving SE from Manitoba into the northern plains pushes shortwave energy through the mid south and southern Appalachian mountains. This will cause the surface low to move eastward through the TN Valley Saturday to our north. A Gulf coast warm front will lift north of the area with numerous showers over SE GA and less coverage over NE FL due to less instability closer to the ridge axis aloft.

Sunday, the surface low near the Carolina coast will lift away to the NE with an extending cold front approaching SE GA. The front will move through SE GA towards the FL/GA state line and nearly stall across NE FL on Monday as a wave of low pressure develops to the west along the central Gulf coast and moves towards the area. This pattern will bring numerous showers and scattered thunderstorms, through there is potential for higher rain chances depending on the strength and timing of the wave of low pressure moving in from the west through the area with high end potential rainfall of 2-3 inches.

Temperatures will begin above normal with low 90s inland and near normal along the coast in the mid to upper 80s. High temperatures will trend to near normal by the end of the weekend into Monday with highs in the mid to upper 80s due to more clouds and rain. Low Temperatures will remain above normal in the low 70s inland and the mid to upper 70s at the coast with below normal lows arriving Monday night over inland SE GA as the cold front sinks southward towards north central FL into early Tuesday.

AVIATION /00Z TUESDAY THROUGH 00Z WEDNESDAY/

VFR conditions with generally light and variable winds continue through the period. Patchy fog will be possible for GNV/VQQ around 08-12Z. Have TEMPOs for lower VSBYs.

MARINE

High pressure will shift over the region early this week with prevailing west to southwest winds, turning southeasterly in the afternoon nearshore from the Atlantic seabreeze circulation. High pressure will shift east of the waters midweek with southerly winds, turning easterly in the afternoon over the nearshore waters from seabreeze circulation. Increasing moisture will bring a return of scattered showers and isolated thunderstorms over the waters by late in the week.

Rip Currents: Long period swells and elevated surf heights continue to subside down into the 2-3 ft range today and expect a solid Moderate Risk of Rip currents through Tuesday.

FIRE WEATHER

- Patchy High Daytime Dispersions Inland Thursday - Patchy Low Daytime Dispersions Saturday Through Monday

The overall flow will steadily shift from the west-northwest to be from the east-southeast by midweek as high pressure shifts northeast of the region. This will allow for the dry air over the area to be steadily replaced with moist air from the Atlantic. With the return of moisture over the area, chances of showers and storms increase by midweek with highest chances over north central FL as scattered showers and isolated storms will be possible Tuesday through Thursday. By the end of the week, the coverage of scattered to numerous showers and isolated storms expands to include most of the area, with higher chances across northeast FL. Decent dispersions for much of the week, with some Patchy High dispersions on Thursday.

Fog Potential...Patchy fog over inland locations Tonight and Tuesday Night.

TIDES/COASTAL FLOODING

Astronomical higher than normal tides will continue into this evening with Minor Flooding occurring during times of high tide within the St. Johns River Basin and along the NE FL Atlantic coast/ICWW. Water levels peak during high tide between 1.5 - 2 feet above Mean Higher High Water (MHHW) through this evening. Lingering influence of this past weekend's full moon and long period swells will continue peak water levels rising 1.5 - 2 feet through Tuesday Evening over Duval county portions of the St Johns river and tributaries and also over the Northeast FL coast and Intracoastal waters from Mayport southward to Flagler County.

PRELIMINARY POINT TEMPS/POPS

AMG 62 90 68 89 / 0 0 10 20 SSI 72 85 74 84 / 0 0 10 10 JAX 68 88 71 86 / 0 10 10 10 SGJ 70 86 72 84 / 0 20 10 10 GNV 68 88 69 88 / 0 20 0 30 OCF 68 89 69 89 / 0 20 10 50

JAX WATCHES/WARNINGS/ADVISORIES

FL...Coastal Flood Advisory until 8 PM EDT Tuesday for FLZ125-138- 225-233-325-333. Coastal Flood Advisory until 8 PM EDT this evening for FLZ132- 137-633. GA...None. MARINE...None.