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

- Localized Flooding Rain Risk Today

- Moderate Rip Current Risk Today - High Risk Wednesday

- Daily Afternoon & Evening Thunderstorms

NEAR TERM /THROUGH TONIGHT/

Highlights Through Tonight:

- Unsettled Weather & Cooler Today

- Localized Flood Risk Continues

Cloudy and cooler today with waves of showers and storms as a surface front across the Carolinas early this morning settles farther south and extends across north FL or very near the GA-FL state line by this afternoon. The mid-level trough across the region will edge slightly farther south today with the axis across north Florida. This will bring slightly drier air (PWATs falling below 2 inches under northerly flow) across southeast GA into the afternoon while keeping richer moisture and stronger lift across northeast FL, near and south of the surface front. Higher rain chances this morning will focus across northeast FL and along the Atlantic coast where onshore, breezy northeast winds develop on the northern side of the surface front. Into the afternoon, rain chances expand east to west as diurnal instability increases and another vorticity max within the mid level trough pivots southward across north-central FL. Breezy northeast winds develop north of the front along the southeast GA coast this morning, then east-northeast winds expand southward through the afternoon as the surface front settles farther south of north Florida as high pressure strengthens northeast of the region. An inverted coastal trough begins to form tonight over the adjacent coastal waters, with elevated northeast winds along the coast tonight and a chance of coastal showers and isolated storms.

The main short-term weather hazard will continue to be localized flooding rainfall, especially along the coast and inland across northeast Florida near and south of the surface front this afternoon and into the evening. Rich, deep layer moisture with PWAT near the daily max today of 2.3 inches at JAX combined with weak steering flow near 5 kts will create slow moving showers and storms, that could train near the front and inland from the coast as onshore flow develops.

Leaned on the cooler side of temperatures today given lingering clouds and waves of rainfall with highs in the low/mid 80s for locations near and east of Interstate 95 and the St. Johns River basin to the mid/upper 80s farther inland. Some of the hourly guidance is trending about 3-5 deg cooler for many locations today, so adjustments may be needed depending on if cloud breaks occur later today. Tonight, lows will range in the 70s under elevated NE winds along the coast.

SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/

Main Highlights This Period:

- Localized Heavy Rain

- Daily Thunderstorms Chances

The cold front over the area shifts towards north central FL on Tuesday and will begin to weaken as it sits over central/north central FL on Wednesday. Northeasterly onshore flow continues at the start of the period as gusty conditions is anticipated along the coast, with the stronger winds along SE GA coastal locations and local waters. With this flow in place, showers and storms will push in from the local waters and towards inland locations from northeast to southwest through much of the day. Stronger storms are expected to develop over inland locations with peak diurnal heating during the afternoon hours. Forecast PWATs sit around the 1.75" to 2" mark on Tuesday, so could still some heavy downpours with any shower or storm that develop.

By Wednesday, a more easterly flow develops which will continue to push activity in from the Atlantic coast towards inland locations by the afternoon hours. Heavy downpours will again be likely as a bit more moisture will be aloft from the onshore flow.

Cooler temperatures on Tuesday behind the front with highs in the mid to upper 80s. A bit warmer temperatures on Wednesday as highs will be in the upper 80s to lower 90s.

LONG TERM /THURSDAY THROUGH SUNDAY/

Main Highlights This Period:

- Daily Thunderstorms Chances

Chances of precipitation look to steadily decrease through the end of the week, with chances of 60% on Thursday trending down to the 30% to 50% by the weekend. Southerly then southwesterly flow develops past midweek and into the upcoming weekend. Guidance continues to show another cold front dipping near SE GA on Saturday, but may stall north of the area on Sunday.

Temperatures in the mid 80s to lower 90s during the back half of the upcoming week as southwesterly develops heading into this weekend

AVIATION /06Z MONDAY THROUGH 06Z TUESDAY/

Unsettled weather with periods of restrictions as a surface front moves across the area this morning and stalls across north Florida through tonight. Early this morning fading stratiform rain will approach GNV and VQQ from the west the next couple of hours with TS activity quickly fading. Winds already shifted to NNE at SSI trailing surface front passage, with the wind shift expected at JAX, CRG, VQQ and SGJ by 15z then GNV by 18z. Transient ceiling restrictions of MVFR to LIFR expected at times this morning as the front shifts southward across the terminals and added PROB30 for scattered morning showers and isolated storms that will drift inland from the coast and also be possible near GNV and VQQ along the stalling front. Included TEMPOs this afternoon into the evening based on higher TS chances.

MARINE

A front stalls across north Florida today then shifts south of the waters tonight into Tuesday as high pressure strengthens to the northeast. A brief period of Small Craft Exercise Caution conditions is possible mainly over the Georgia waters Tuesday as a coastal trough develops offshore, then elevated combined seas may bring Small Craft Exercise Caution conditions to the outer waters on Wednesday as the coastal trough begins weaken. High pressure builds east of the local waters Thursday then extends across the Florida peninsula Friday into the weekend with a return of westerly winds and the afternoon east coast sea breeze.

Rip Currents: Rip current risk increases from north to south today as onshore flow develops with moderate risk for all local beaches. By Tuesday, solid moderate to possibly high rip current due to stronger and more persistent ENE onshore winds. High risk likely for all local beaches by Wednesday with persistent onshore flow and elevated surf with breakers 3-5 ft.

FIRE WEATHER

- Low Dispersions Over Northeast Florida On Monday

A cold front is expected to shift southward across southeast Georgia Today. Low daytime dispersion expected this afternoon across north central FL, possibly Tuesday due to more cloudiness and elevated rain chances. Surface winds and transport winds will begin to transition to northeast to east behind the front Today. Elevated rain chances are expected again on Tuesday and Wednesday.

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 next 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, extended probabilistic guidance keeps water levels below action stage late Tuesday through Wednesday both along the local Atlantic coast and within the St. Johns River basin.

PRELIMINARY POINT TEMPS/POPS

AMG 89 72 87 72 / 60 40 70 20 SSI 87 77 87 78 / 60 60 60 40 JAX 89 73 88 74 / 80 50 70 20 SGJ 87 75 86 76 / 70 40 60 20 GNV 89 72 88 73 / 70 60 80 20 OCF 90 73 89 73 / 70 50 80 30

JAX WATCHES/WARNINGS/ADVISORIES

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