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

- High Risk for Rip Currents Today Most Local Beaches. High Risk Wednesday All Local Beaches. Elevated Rip Current Risk through Thursday

- Daily Afternoon & Evening Thunderstorms Tuesday to Sunday. Main Hazards: Locally Heavy Rain, Lightning & Gusty Winds to 40 mph

NEAR TERM /THROUGH TONIGHT/

Highlights Through Tonight:

- Breezy onshore/easterly winds today

- Passing gusty showers & inland mainly afternoon storms

- High Risk for Rip Currents Southeast GA Beaches & Elevated Tides

Taste of fall continues for southeast GA and northeast Florida today with waves of coastal showers and increasingly breezy northeast to east winds as a weak coastal trough develops over the adjacent coastal waters. Low chance (< 10%) of a morning coastal thunderstorm focused south of St. Augustine where deeper moisture resides near the departing surface front across north-central FL. Through the day, shower activity will expand inland with diurnal heating, but convective depth will be limited across much of southeast GA and and near and north of the FL Interstate 10 corridor as drier mid and upper level air from the north filters across the area. Thus, expected mostly diurnally driven showers into the afternoon for locations north of I-10 while the better coverage of afternoon showers and thunderstorms focuses across north-central FL, generally from St. Augustine toward Gainesville southward.

This evening, inland showers fade while coastal showers and isolated thunderstorms continue as the coastal trough lingers offshore. After midnight, the coastal trough begins to break down and weaken as surface high pressure offshore of the mid-Atlantic region settles southward. Could see an influx of shower activity toward daybreak, shifting farther inland as the trough axis also shifts westward.

High temperatures trend a little warmer into today nearing 90 toward the Interstate 75 corridor while breezy onshore winds keeps coastal areas cooler with highs in the mid 80s. Tonight, lows will continue to range in the 70s to near 80 toward the coast.

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/

Main Highlights This Period:

- Daily Thunderstorms Chances

A cold front will sit over the FL peninsula through midweek, weakening and dissipating by Thursday evening. The overall flow will shift from easterly to southeasterly and eventually southwesterly by Thursday afternoon as mid level ridging sits off the Atlantic coast. With easterly-southeasterly onshore flow continuing on Wednesday, shower and storm activity will push towards inland locations by the afternoon hours. Wednesday highs will be in the upper 80s to lower 90s, with the coolest temperatures along the coast with the onshore flow. As ridging develops over the western Atlantic, deep southwesterly flow makes a return, bringing elevated moisture once again with PWATs rising to the 2.2" to 2.4" range. The overall flow will allow for the gulf breeze to push inland, which in turn will direct showers and storms from west to east. By the afternoon, mergers between the breezes will likely be along the eastern portion of the area near the I-95 corridor. Thursday highs will be a bit warmer as most locations will have temperatures in the lower 90s, with mid 80s to lower 90s along the coast.

LONG TERM /FRIDAY THROUGH MONDAY/

Main Highlights This Period:

- Daily Thunderstorms Chances

Southwesterly flow ahead of a frontal boundary as it begins to slow and stall over central GA this weekend. Chances of precipitation look to remain in the 60% range Friday/Saturday with the Weather Prediction Center having the entire area under a 'Marginal' risk of excessive rainfall both days. Chances begin to trend down to the 30% to 50% for a majority of the area with north central FL remaining in the 60% range on Sunday/Monday. Temperatures will predominantly be in the lower 90s through the upcoming weekend into next week.

AVIATION /12Z TUESDAY THROUGH 12Z WEDNESDAY/

VFR ceilings and occasional MVFR ceilings expected through 14-16Z as moist flow between a coastal trough to the east and high pressure to the north brings in periodic showers onshore and inland. Northeast winds around 10 knots at the coast will increase to 12-15 knots with gusts to 25 knots while lighter inland winds 4-6 knots increase by 16Z to 10-12 knots with gusts near 20 knots. Have VCSH for all sites this afternoon with some MVFR ceilings as times as the coastal showers move onshore as the trough remains east of the terminals, but am including PROB30 groups for TSRA at VQQ, GNV, SGJ while PROB30 groups in place for JAX and CRG for MVFR VSBY and CIGs, while SSI will remain north of the better batch of showers this afternoon with no PROB30 groups as dry air limits coverage there.

VFR conditions prevail after 00Z-02Z and shower chances inland will diminish after 00Z while persisting at SSI through 06Z as the coastal trough weakens and moves onshore the Georgia coast as high pressure to the north shifts more to the northeast. Then, MVFR ceilings will redevelop in the early morning hours at GNV, JAX, and VQQ after 06Z.

MARINE

A coastal trough develops today and persists through Wednesday morning with waves of gusty showers and isolated thunderstorms. The trough begins to weaken Wednesday night into Thursday as high pressure builds northeast of the region. The high will then extend across the Florida peninsula Friday into the weekend with a return of southwest winds and the afternoon east coast sea breeze.

Onshore ENE winds strengthen today with building surf. With elevated ENE wind surge over the waters, extended the high rip current risk southward from southeast GA to included northeast FL beaches down the St. Johns county coast. Flagler county remains under a Moderate rip current risk today. Surf heights increase to 2-4 ft through the evening. High rip current risk likely for all local beaches Wednesday due to persistent onshore flow and elevated surf.

FIRE WEATHER

A cold front will be sit across central Florida through midweek before weakening and dissipating by Thursday evening. Increased rain and storm chances are forecast each day as onshore winds brings morning coastal showers which will spread towards inland locations throughout the day and increase in coverage. There remains potential for locally heavy downpours through mid-week. Overall, dispersion will be fair to good Tuesday and Wednesday. Winds will shift to southerly/southwesterly Thursday through the weekend as ridging develops off the east coast.

Fog Potential: Gusty and erratic winds will occur with thunderstorm activity. Patchy inland morning fog possible each day.

HYDROLOGY

Coastal water levels begin to increase this week with the approach of the New Moon on Sept 11th and breezy onshore easterly winds late Tonight through Wednesday, with the peak winds across the local waters and coast Tuesday. At this time, guidance and observations show that water levels will be near and just above the action stage through Wednesday both along the local Atlantic coast and within the St. Johns River basin.

PRELIMINARY POINT TEMPS/POPS

AMG 90 73 90 72 / 20 10 60 10 SSI 87 77 87 78 / 50 60 60 20 JAX 89 75 89 75 / 40 30 50 10 SGJ 86 77 88 76 / 50 30 40 10 GNV 89 74 90 73 / 50 20 60 10 OCF 90 74 91 74 / 70 30 60 20

JAX WATCHES/WARNINGS/ADVISORIES

FL...High Risk for Rip Currents through late tonight for FLZ124-125-233- 333. GA...High Risk for Rip Currents through late tonight for GAZ154-166. MARINE...None.