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 Thunderstorms Each Day Through the Weekend. Strong Storm Potential Each Afternoon and Evening. Daily Rounds of Heavy Downpours May Cause Localized Flooding

- Increasing Rip Current Potential Later This Week Through the Weekend

NEAR TERM /THROUGH TONIGHT/

Main Highlights through Tonight:

- Isolated strong storm possible this afternoon into evening

Southwesterly flow, forming along the stalled front extending over the forecast area from out of the northwest and north of high pressure ridging extending over the Florida peninsula from out of the east, will continue to bring showers and storms through the afternoon and into this evening. Convection will initially be more inhibited for southeast Georgia due to drier air associated with the frontal boundary with scattered showers and storms more likely to develop over northeast Florida and along the coast as the southwest sea breeze collides with the east coast sea breeze, pinned near the shoreline. Drier air over the region will begin to become more disorganized and recede northward tonight as the high pressure ridging from the east presses in. High temperatures this afternoon will reach up into the lower 90s with overnight low temperatures dropping down into the lower 70s for inland areas and in the mid 70s along the coastline. Heat index values this afternoon will rise to be above 100, however conditions are expected to remain below heat advisory criteria today.

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/

Main Highlights This Period:

- Isolated strong to severe thunderstorms each afternoon and evening

Wednesday, a closed mid to upper level trough over the southern appalachians will open up as broad troughing moves into the upper Midwest while Atlantic ridging aloft centered north of Bermuda will extend southwestward into south FL. At the surface, the frontal boundary just north of the area will dissipate as support weakens aloft and the Atlantic surface high pressure ridge axis will extend into southern/central FL peninsula. Light south to southwest low level flow will allow the Atlantic seabreeze to shift inland past I- 95 before merging with the Gulf seabreeze west of US-17. Higher moisture levels across NE FL will support scattered thunderstorms becoming numerous between US-17 and highway 301 while drier air across SE GA limits chances to isolated to widely scattered storms in the afternoon to early evening. Light southerly winds 5-10 mph will turn southeasterly behind the Atlantic seabreeze 10-15 mph with gusts to 20 mph along the coast and behind seabreeze passage.

High temperatures will reach the lower 90s away from the coast with coastal highs in the upper 80s.

Wednesday night, convection will fade by 10PM across most of the area while isolated storms continuing across inland SE GA as some shortwave energy aloft perpetuates activity past midnight. Dry conditions return after midnight with gradually clearing skies and lows in the low 70s inland and mid 70s at the coast.

Thursday, the open trough will lift away from the region while Atlantic ridging aloft builds between Bermuda and the Delmarva peninsula. The Atlantic surface ridge axis will extend across SE GA from the northeast with southeast low level flow that will bring in breezy southeasterly winds turning easterly behind the Atlantic seabreeze. A ribbon of higher moisture will stretch from the Carolinas southward into the FL peninsula and support scattered coverage of thunderstorms near the coast becoming numerous west of highway 301 where Atlantic/Gulf seabreeze merger is expected.

Highs on Thursday will match Wednesdays values in the low 90s inland and the upper 80s at the coast.

Each day, potential for isolated strong storms will exist along storm cell mergers with outflow/seabreeze boundaries that would support gusty downburst winds 40-50 mph (mainly from heavy water loading due to high moisture levels) along with frequent lightning and locally heavy downpours that could lead to minor flooding in low lying, flood prone, and urban areas given slow storm motions.

LONG TERM /FRIDAY THROUGH TUESDAY/

Main Highlights This Period:

- Isolated strong to severe thunderstorms each afternoon and evening

Friday into Sunday, high pressure remains east northeast of the region over the Atlantic waters with an inverted trough over the southeast coast into NE FL. This will allow for increased chances for showers and thunderstorms inland due to east to southeast onshore flow.

The high will sink southward early next week with the surface ridge axis shifting into central FL. This will allow more southerly low level flow pattern and lead to Gulf and Atlantic seabreezes merging east near I-95 and US-17 corridors. Drier air under the ridge will limit convection to scattered coverage.

Highs will begin the period a little below average Friday, be near average this weekend, and increase to above average into early next week due to less storm coverage. Lows will be a bit above normal this weekend and then dip back to around normal Monday and Tuesday evenings as a slightly drier airmass shifts over the area.

AVIATION /18Z TUESDAY THROUGH 18Z WEDNESDAY/

Isolated to scattered showers with embedded thunderstorms will be moving through the forecast area this afternoon and through the evening. Sustained winds will be primarily out of the southwest at about 8 to 10 knots with coastal areas shifting to be more out of the south as the coastal sea breeze builds. Convection will dissipate by around 01z-03z with more mild and variable winds in place overnight and into Wednesday morning.

MARINE

Frontal boundary will remain stalled north of the waters today and then dissipate on Wednesday. Offshore flow continues this morning with a shift to south-southeasterly this afternoon and evening in the wake of the pinned Atlantic sea breeze. High pressure ridge will build north of the waters by Wednesday with a return to a prevailing southeast onshore flow that will become easterly by Friday and Saturday.

Rip Currents: A wind shift to a more southeast/onshore flow along with some increase in long period swells will build surf/breakers to 2-3 feet by mid-week with a Moderate rip current risk expected and potentially surf/breakers of 3-4 feet by Friday into the upcoming weekend.

FIRE WEATHER

Drier air shifting in from the north and west will limit coverage of thunderstorms today to isolated to widely scattered except around the southern St Johns river basin south of SR 207/Palatka with light southwest winds inland and south to southeasterly winds behind the Atlantic seabreeze as it remains pinned east of I-95. Dispersions will be in the good range today with fair to good values this week through Friday. Scattered to numerous thunderstorms will focus inland Wednesday into Friday as east southeasterly onshore flow develops due to high pressure anchoring northeast of the region. Isolated strong thunderstorm potential will remain each afternoon with storm outflows causing sudden and erratic wind shifts, locally stronger winds, and dangerous cloud to ground lightning in and near thunderstorms.

Fog Potential: Significant fog development is not expected.

PRELIMINARY POINT TEMPS/POPS

AMG 72 92 72 92 / 20 30 40 60 SSI 77 89 78 89 / 20 10 30 30 JAX 73 91 73 91 / 20 30 20 40 SGJ 74 90 75 90 / 20 30 20 40 GNV 72 90 72 91 / 10 50 30 70 OCF 73 89 73 90 / 10 50 30 70

JAX WATCHES/WARNINGS/ADVISORIES

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