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 Afternoon & Evening Thunderstorms Inland Today. Isolated Strong Storms Possible for Locations West of U.S. Highway 301. Wind Gusts of 35-45 mph, Frequent Lightning Strikes, and Small Hail Possible

- Scattered to Numerous Afternoon & Evening TStorms Sun through Wed. Isolated Strong Storms and Locally Heavy Rainfall Possible

- Moderate Rip Current Risk Continues at All Area Beaches

- Strengthening Onshore Winds Will Increase Marine Hazards from Late Wednesday through Friday

NEAR TERM /THROUGH TONIGHT/

Main Highlights through Tonight:

- Scattered Afternoon and Early Evening Thunderstorms at Inland Locations.

- Isolated Strong Storms Possible at Inland Locations, with Gusty Winds, Frequent Lightning Strikes and Possibly Small Hail.

- Moderate Rip Current Risk Continues at All Area Beaches.

Overnight surface analysis depicts a surface trough approaching the east central FL Atlantic coast, while weakening high pressure (1019 millibars) was shifting westward across the lower Mississippi Valley. Meanwhile, a frontal boundary extends from the Upper Midwest southeastward through the Tennessee Valley and the Carolinas. Aloft...a Tropical Upper Tropospheric Trough (TUTT) was pushing westward across central FL. Otherwise, "Heat Wave" ridging remains centered over northeastern Texas and the Ozarks, with this feature extending its axis northeastward across the southern Appalachians. Latest GOES-East derived Total Precipitable Water imagery indicates that PWATs remain above late September climatology across our region, with values generally around 1.75 inches for locations south of Interstate 10 and around 2 inches for locales north of I-10. Showers and thunderstorms were being triggered by the combination of the surface trough and TUTT feature across the Atlantic waters adjacent to east central FL, with a few showers extending north of this feature to near Flagler Beach. Otherwise, patches of mid and high altitude cloud cover were progressing across our region, with calm winds at most locations allowing temperatures and dewpoints to fall to the upper 60s and lower 70s as of 08Z.

The TUTT feature and its accompanying surface trough will slow its westward movement further today as these features exit FL's Gulf coast by this afternoon. Meanwhile, a ribbon of deeper moisture will continue to reside across southeast GA through tonight as a frontal boundary over the Carolinas stalls to the north of our area. Meanwhile, a more subsident air mass will remain in place across coastal portions of northeast FL and southeast GA to the north of the TUTT feature, which will likely limit shower coverage to isolated for these locations. Persistent east-northeasterly winds could drive a few of these showers onshore this morning, with the inland moving Atlantic sea breeze boundary then becoming the focus for scattered afternoon showers and thunderstorms across inland portions of northeast and north central FL, mainly for locations along and west of the U.S. Highway 301 corridor. Scattered afternoon and early evening thunderstorms are also expected to develop across interior portions of southeast GA, with activity forecast to move slowly west or west-southwestward. Relatively cool temperatures aloft associated with the nearby TUTT could cause a few storms to pulse and become strong this afternoon, with any stronger activity being capable of producing downburst winds of 35-45 mph, along with frequent lightning strikes and possibly small hail. Weaker onshore flow today should allow coastal highs to climb to the upper 80s, while highs at inland locations generally reach the lower 90s, with heat index values peaking around 100 at most locations this afternoon.

The TUTT cell and its accompanying surface trough will begin to stall to the west of the Tampa Bay region tonight, with subsidence shifting west of our area overnight and low level flow veering to east-southeasterly. This evolution of the weather pattern will likely result in increasing convection overnight over the Atlantic waters, with light onshore winds potentially advecting some of this activity towards coastal locations during the predawn hours on Sunday. Evening convection over inland southeast GA, the Suwannee Valley and north central FL should progress west of the Alapaha and Suwannee Rivers by the mid-evening hours, with mid and high cloud cover likely persisting across much of our area overnight. Lows will mostly fall to the low and mid 70s across our region.

SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/

Main Highlights This Period: (Sunday through Monday night)

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

Upper low lingering over the eastern Gulf will provide additional instability to the region into early next week. At the surface, ridging over the eastern seaboard weakens but ENE flow remains. A moist airmass (PWATs 1.8-2.1") continue to filter into the area from the Atlantic. For Sunday and Monday, an early start is anticipated to showers and storms as the Atlantic sea breeze shifts inland to the I-95 corridor by noon. Showers and storms increase as the Atlantic sea breeze shifts well inland and merges with the Gulf sea breeze along and west of I-75 in the late afternoon and evening. A few stronger storms could produce gusty winds and heavy downpours. Highs will range from the upper 80s along the coast to the low 90s inland. Overnight lows will be in the 70s.

LONG TERM /TUESDAY THROUGH FRIDAY/

Main Highlights This Period: (Tuesday through Friday)

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

The closed mid/upper Low over the northeastern Gulf will weaken 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 build in behind the front lowering coverage to be more scattered for the end of the week. A slight cooling trend next week with highs in the upper 80s to low 90s on Tuesday become low-upper 80s area-wide. Overnight lows in the 70s then dip into the mid 60s to low 70s.

AVIATION /12Z SATURDAY THROUGH 12Z SUNDAY/

Outside of influence from an isolated thunderstorm, VFR conditions maintain through the morning, afternoon, and evening hours. Light northwest to northerly surface winds will become sustained around 5 knots towards 14Z before shifting to northeasterly and easterly at 5- 10 knots this afternoon. Isolated showers and potential TSRA may impact inland sites along the I-75 corridor (at KGNV) between 20z- 00z this evening. Tonight, east to southeasterly surface winds fall to around 5 knots during the evening hours will then diminish overnight. As winds calm, light fog may develop at KVQQ during the predawn hours Sunday.

MARINE

A surface trough and disturbance aloft moving slowly westward across the Florida peninsula this morning will emerge over the southeast Gulf this afternoon. Widely scattered showers and possibly a few thunderstorms should remain confined to the waters from around St. Augustine southward today, with coverage then slowly increasing throughout our local waters after midnight on Saturday night and Sunday. Scattered to numerous showers and thunderstorms are then expected early next week as the disturbance aloft moves slowly r northeastward across our area. East to northeasterly winds will otherwise prevail through the early portions of next week, with speeds and seas remaining below Caution levels. Strong high pressure building over southeastern Canada and New England towards the middle portion of next week will then wedge down the southeastern seaboard, resulting in surge of northeasterly winds that will likely bring Small Craft Advisory conditions to our local waters beginning later on Wednesday and continuing through the late portions of next week.

Rip Currents: Persistent east-northeasterly winds will keep a moderate rip current risk in place through the weekend and early portions of next week at all area beaches. A high risk is likely beginning later on Wednesday and continuing through the late portions of next week as northeasterly winds strengthen and breaker heights build.

FIRE WEATHER

Northeast to east winds will continue through early next week. Fair to good daytime dispersions prevail this weekend. Isolated showers and storms develop along the sea breezes with the sea breeze merger along and west of the I-75 corridor in the late afternoon and evening. Storm coverage increases to more numerous on Sunday and Monday.

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 71 90 71 / 40 40 30 0 SSI 89 75 88 75 / 20 30 40 10 JAX 90 72 89 73 / 20 20 30 10 SGJ 88 76 87 74 / 20 10 20 20 GNV 90 71 90 71 / 30 0 60 10 OCF 91 71 91 71 / 50 10 60 10

JAX WATCHES/WARNINGS/ADVISORIES

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