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 Mainly Afternoon & Evening TStorms through Wed. Isolated Strong Storms Possible for Locations West of I-95 this Afternoon through. Wind Gusts of 35-45 mph, Frequent Lightning Strikes, and Small Hail Possible. Locally Heavy Rainfall Possible on Monday Afternoon and Evening

- Moderate Rip Current Risk Continues at All Area Beaches through Midweek

- Strengthening Onshore Winds Will Increase Marine Hazards from Late Wednesday through Next Weekend. High Risk for Rip Currents and Rough Surf Expected at Area Beaches. Minor Coastal Flooding Possible Around Times of High Tide Late this Week

NEAR TERM /THROUGH TONIGHT/

Main Highlights through Tonight:

- Scattered to Numerous Mainly Afternoon and Early Evening Thunderstorms Today.

- Isolated Strong Storms Possible at Inland Locations Late this Afternoon and Early this Evening.

- Moderate Rip Current Risk Continues at All Area Beaches.

Early morning surface analysis depicts a trough over the spine of the FL peninsula, with a weak pressure pattern otherwise prevailing across our region. Meanwhile, high pressure (1024 millibars) positioned over coastal New England has pushed a "backdoor" frontal boundary southward across the southern Appalachians, with this boundary extending eastward to the coastal Carolina region. Aloft...a Tropical Upper Tropospheric Trough (TUTT) was nearly stationary as it spins just west of the Tampa Bay region. Otherwise, "heat wave" ridging over eastern Texas, the Ozarks, and the lower Mississippi Valley was in the process of weakening as troughing over the Rockies and the Southern Plains progresses slowly eastward. Latest GOES-East derived Total Precipitable Water imagery indicates that PWATs remain above late September climatology across our area, with values in the 1.8 - 2 inch range. Isolated to widely scattered showers were weakening as they progress slowly west-southwestward across the Okefenokee Swamp and the Suwannee Valley, while convection associated with the aforementioned TUTT feature was blossoming over the offshore waters north of St. Augustine. Patches of mostly mid and high altitude cloud cover were drifting across our skies, with temperatures and dewpoints in the 70s area-wide as of 08Z.

A rather stagnant weather pattern is expected across our area today as the TUTT feature and its accompanying surface trough remain stationary near Tampa Bay and over the FL peninsula, respectively. Low level east-northeasterly flow will prevail, with a moist and unstable atmosphere promoting scattered to numerous showers and thunderstorms that will progress westward. Scattered convection over the Atlantic waters early this morning should edge towards coastal locations as the morning progresses, with activity then increasing in coverage and intensity this afternoon as the Atlantic sea breeze pushes showers and thunderstorms west of the I-95 corridor by the mid to late afternoon hours. Relatively cool temperatures aloft, supplied by the TUTT feature, should allow for a few storms to "pulse" and become strong to the west of the I-95 corridor later this afternoon and possibly continuing in the Suwannee Valley and portions of interior southeast GA this evening, with stronger storms being capable of producing downburst winds of 35-45 mph, frequent lighting strikes, heavy downpours, and possibly small hail as well. Breaks in the mid and high altitude cloud cover this morning should allow highs to climb to the upper 80s and lower 90s, with heat index values peaking around 100 before convective coverage and cloud cover increases later this afternoon.

Convection may linger early this evening across the Suwannee Valley and inland southeast GA, with this activity then shifting west of the Alapaha and Suwannee Rivers before midnight. Convergent low level east-northeasterly flow and plenty of available moisture should allow for widely scattered showers and possibly a few embedded thunderstorms to develop and blossom over the Atlantic waters again overnight, and this activity should approach coastal southeast GA and portions of coastal northeast FL before sunrise on Monday. Patchy fog formation will also be possible at inland locations towards sunrise, mainly west of the U.S. Highway 301 corridor. Lows will generally fall to the 70-75 degree range across our area later tonight.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/

Main Highlights This Period: (Monday through Tuesday night)

- Scattered to Numerous Mainly Afternoon and Evening Showers and Thunderstorms Expected.

- A Few Strong Storms with Locally Heavy Rainfall are Possible, Especially on Monday.

The TUTT feature and its accompanying surface trough will move slowly northeastward across our area on Monday, with weak cyclogenesis then possible off the southeastern U.S. seaboard on Tuesday as these features lift slowly away from our region. Low- level onshore winds will continue, and convection may get an early start on Monday at coastal locations and along the I-95 corridor as temperatures aloft continue to gradually cool in association with the TUTT moving overhead. Activity will then progress slowly inland as the day continues, with a few strong storms possible further inland. Slow storm motion could also result in locally heavy rainfall amounts. Highs on Monday should again climb to the upper 80s and lower 90s, with plenty of humidity allowing heat indices to again peak around or just above 100 at inland locations.

Convection should continue to shift west of our area during the evening hours, with nocturnal activity flaring over the Atlantic waters then edging towards coastal locations by early Tuesday morning. Low level flow will become more southerly by Tuesday afternoon as the TUTT feature and developing surface low progress away from our region, with plenty of moisture left behind allowing for scattered to numerous showers and thunderstorms to develop along inland moving sea breezes on Tuesday afternoon. Temperatures aloft will not be quite as cool on Tuesday, but highs reaching the upper 80s and lower 90s could still provide enough instability for storms to "pulse" as mesoscale boundaries collide during the afternoon and early evening hours at inland locations, where isolated strong storms containing briefly gusty winds, frequent lightning strikes, and slow moving, locally heavy downpours will be possible. Activity will dissipate by the mid to late evening hours at inland locations, with late night convection again possibly impacting coastal locations before sunrise on Wednesday. Lows will remain mostly in the low and mid 70s across our area.

LONG TERM /WEDNESDAY THROUGH SATURDAY/

Main Highlights This Period: (Wednesday through Sunday):

- Scattered to Numerous Showers and Thunderstorms Continue on Wednesday.

- Strengthening Northeasterly Winds will Bring Increasing Marine Hazards to Coastal Locations on Thursday and Friday.

- Cooler Temperatures are Forecast Later this Week and into Next Weekend Area-Wide.

- Minor Coastal Flooding Possible Around Times of High Tide Late this Week and Next Weekend.

Troughing will dig over the eastern half of the nation during the long term period, with strong surface high pressure building over southeastern Canada and New England wedging down the southeastern seaboard on Wednesday afternoon and evening. This weather pattern will drive a cold front southward into our region, with deep moisture pooling downstream of this front across our area. Scattered to numerous showers and thunderstorms should continue across our area on Wednesday, especially as the front approaches during the afternoon and evening hours. A few strong storms and locally heavy rainfall will continue to be possible, with activity likely concentrating across inland portions of northeast and north central FL during the afternoon and evening hours as our local pressure gradient tightens, creating breezy northeasterly winds along the I- 95 corridor by the late afternoon hours. Highs will range from the mid 80s at coastal locations to around 90 at inland locations.

Showers and thunderstorms may continue on Wednesday night across northeast and north central FL as the frontal boundary shifts southward through our area, with breezy northeasterly winds potentially producing waves of coastal showers and possibly a few embedded thunderstorms throughout the night along the I-95 corridor. Cool air advection in the wake of the frontal passage could drop lows to the upper 60s despite an abundance of cloud cover across southeast GA on Wednesday night, with low to mid 70s persisting elsewhere.

Strong high pressure will persist over New England late this week, with low pressure initially offshore of the southeastern states then potentially strengthening off the Mid-Atlantic coast. This weather pattern will keep breezy northeasterly winds in place on Thursday along the I-95 corridor, and these winds may shift to northerly by Friday and Saturday, potentially ushering in a cooler and drier air mass into our region. Gusty onshore winds on Thursday should still provide coastal showers for coastal northeast FL, but rain chances could then decrease by Friday and Saturday depending on how the coastal storm evolves off the Mid-Atlantic coast. Highs should remain in the low and mid 80s from Thursday onward area-wide, and lows could fall into the lower 60s for inland southeast GA and the mid to upper 60s elsewhere inland by late this week and into next weekend. Coastal lows may fall to around 70 as winds become more northerly and cool air advection continues later this week and into next weekend.

Astronomical tides will be on the rise later this week due to the upcoming Full "Harvest" Moon, and minor coastal flooding during times of high tide along the Atlantic coast and within the St. Johns River basin will be a possibility later this week and into next weekend, all depending on the strength and positioning of coastal low pressure to our north and the trajectory of surface winds.

AVIATION /12Z SUNDAY THROUGH 12Z MONDAY/

More active convective day this afternoon. Though there is potential for isolated coastal showers through 16z, most shower and thunderstorm development will focus along the inland moving Atlantic sea breeze. Highest confidence for downpours and thunderstorm influences will be at inland airfields 40-70% this afternoon and early evening (18-23z). Downpours will restrict visibility at times at KJAX/KVQQ/KGNV with visibility briefly falling to IFR or lower with +TSRA. Light northwest to northerly surface winds will shift to northeasterly at 5-10 knots by 16Z and then easterly around 10 knots by 20Z. Surface winds will then shift to southeasterly with diminishing speeds after 01Z this evening. As winds trend calm, there will be potential for patchy low stratus and light fog at inland airfields after 08z.

MARINE

Surface troughing and a disturbance aloft located just west of Tampa Bay will remain nearly stationary through tonight before lifting slowly north-northeastward across our local waters by Monday night and Tuesday. Scattered showers and thunderstorms will remain possible through tonight, with coverage then increasing from Monday through at least Thursday. East-northeasterly winds will prevail through Tuesday, with speeds and seas remaining below Caution levels outside of thunderstorm activity. Strong high pressure building over southeastern Canada and New England on Tuesday will begin to wedge down the southeastern seaboard on Wednesday afternoon and evening, creating a surge of northeasterly winds that will likely create Small Craft Advisory conditions across our local waters by Thursday and Friday.

Rip Currents: Persistent east-northeasterly winds will keep a lower-end moderate risk in place through midweek at all area beaches. A surge of strengthening northeasterly winds and building breaker heights will arrive on Wednesday evening, and a high risk is likely at all area beaches on Thursday and Friday, possibly continuing into next weekend.

FIRE WEATHER

LOW DAYTIME DISPERSION VALUES FOR COASTAL SOUTHEAST GEORGIA AND - Portions Of Coastal Northeast Florida Today

Scattered to numerous showers and thunderstorms are expected to develop each day through Thursday, mainly during the afternoon and evening hours. Activity will generally progress from east to west, with showers and thunderstorms concentrating along the Interstate 10 corridor, the Suwannee Valley, and the Okefenokee Swamp this afternoon through early this evening. Otherwise, east-northeasterly surface and transport winds will prevail through Tuesday, followed by gradually strengthening northeasterly surface and transport winds on Wednesday, with stronger speeds then forecast on Thursday and Friday. Lighter speeds today will yield marginally low daytime dispersion values for coastal southeast Georgia and portions of coastal northeast Florida, with generally poor values forecast elsewhere, except fair values for north central Florida. Poor to fair daytime dispersion values will continue through midweek, except for good values across inland southeast Georgia on Wednesday.

Fog Potential...Patchy fog formation is possible across inland portions of southeast Georgia, the Suwannee Valley and inland portions of north central Florida during the predawn and early morning hours on Sunday and Monday.

PRELIMINARY POINT TEMPS/POPS

AMG 91 70 91 70 / 40 20 30 0 SSI 87 75 88 74 / 30 30 40 20 JAX 89 71 90 72 / 50 20 50 10 SGJ 87 75 88 74 / 30 10 40 20 GNV 89 71 91 71 / 60 30 70 10 OCF 90 71 91 72 / 50 20 70 20

JAX WATCHES/WARNINGS/ADVISORIES

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