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

- High Risk of Rip Currents Across Northeast Florida Beaches Today. Moderate to High Risk for Rip Currents Through the Weekend

NEAR TERM /TODAY THROUGH TONIGHT/

Main Highlights:

- Isolated strong storms possible this afternoon into evening - High Risk of Rip Currents Developing Today for northeast FL beaches, Moderate risk for southeast GA beaches Today Deep layer ridging will remain north of the area through this period while an inverted surface trough approaches and moves through the forecast area from the east. Deep tropical-like moisture will rise to about 2.2 inches, or far wetter than normal, while the southeast flow pushes this deep moisture further inland through the afternoon and evening. Low level convergence and greater instability will lead to scattered to numerous showers and thunderstorms through the day as the steering flow shifts from east to southeast to south- southeast late tonight.

Expect to see scattered showers and a few storms in the morning along the coastal areas and the marine waters, and then inland during the afternoon. Will advertise POPS of about 40-70 percent for northeast FL, and 20-40 percent for inland southeast GA where the forcing for convection looks weaker. Convection is expected to fade in the evening, but stay elevated for the coastal areas and the marine waters given the position of the inverted trough. Most of all the guidance, including the HREF and REFS, show the best potential for localized heavy rainfall/flooding for the coastal counties from Flagler Beach to Fernandina Beach. Localized amounts may be to near 3 inches in a few spots through tonight. Sampled soundings from the NAM show lingering dry air aloft which could aid in a strong storm today that may result in gusts of 45-55 mph. If cells organize to a broken line/multi-cell pattern, then a downburst pulse severe storm is possible.

High temperatures will be near average in the lower 90s inland the upper 80s to near 90 coast with daily peak heat index values near 100-105. Muggy and mild overnight lows will range in the lower 70s inland and mid to upper 70s coast.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/

Main Highlights This Period:

- Isolated strong to severe thunderstorms each afternoon and evening - Localized flooding potential this weekend - High Risk for Rip Currents over Northeast Florida Beaches this weekend

Saturday, Atlantic ridging aloft will be centered over Bermuda and extend into the Southeast US coast with a weak shortwave moving towards the Carolina coast. The surface high pressure ridge axis will extend into GA/SC with an inverted trough lifting from the FL coastal waters to the SE GA coast. Southeasterly flow will weaken and become more southerly by the evening hours as the inverted trough lifts to the north and surface ridge axis reestablishes across north central FL. Very high Precipitable Water levels (PWATs) in excess of 2.25 inches will remain over the area and after morning coastal showers and isolated T'storms lift from the SE GA waters, the trailing shortwave energy, diurnal heating, and progressive Atlantic seabreeze will develop numerous T'storms shifting from I-95 to western counties along I-75 and US-441. High moisture levels and slow storm motions will support slow moving T'storms and heavy downpours (rain rates 2-3 inches per hour) bringing a risk of localized flooding concerns in low-lying, flood prone, and urban locations. WPC has a Marginal risk of Excessive rainfall over the area Saturday for localized flash flooding potential. Isolated stronger T'storms forming along storm cell mergers or outflow boundary collisions may produce gusty wet downburst winds up to 40- 50 mph and frequent lightning.

Highs will be near to slightly below normal Saturday with upper 80s along the coast and around 90 along I-95 and near normal west of I- 95 in the low 90s.

Saturday night, Scattered showers and isolated T'storms will continue well inland until around midnight before fading while scattered showers and T'storms persist over the SE GA coastal through the late evening hours. Mostly cloudy skies will remain with lows in the low/mid 70s inland and the mid/upper 70s along the coast. Sunday, the Atlantic ridge will shift southward over the western Atlantic waters and extend across the FL peninsula as a weak shortwave exits NE from the Carolina coast. Light southerly flow in the low levels will allow both Atlantic/Gulf seabreezes to merge inland with a slight decrease in PWATs to around 2.0 inches supporting scattered to numerous T'storms coverage. Highs will warm on Sunday to near to slightly above normal in the low/mid 90s inland and upper 80s to near 90 at the coast from decreasing clouds from the ridge.

LONG TERM /MONDAY THROUGH THURSDAY/

Main Highlights This Period:

- Daily Afternoon Thunderstorms - Heat Advisory Potential Returns Next Week

Atlantic high pressure ridge will become more centered over the FL peninsula Monday through midweek. The position of the ridge will allow for light west southwest flow to persist over the area as the surface high pressure ridge axis stays across central FL and promote daily seabreeze circulation that will favor the Gulf coast seabreeze progressing further inland towards I-95 while Atlantic seabreeze stay pinned closer to the coast. Decreasing PWATs through the week to near to slightly below normal levels 1.6-1.8 inches will lead to only isolated to Widely scattered T'storm coverage. However, an isolated stronger T'storm could develop with high DCAPE values due to drier air associated with the ridge enhancing wet downbursts.

Temperatures will steadily heat up next week with low to mid 90s inland and near 90 along the coast Monday rising to the mid/upper 90s inland and low/mid 90s along the coast due to the Atlantic seabreeze staying near to just offshore the beaches much of the afternoon and increased sunshine and heights from the ridge. The above normal highs and muggy dewpoints in the mid/upper 70s will support peak heat indices into heat advisory levels of 108-110 much of next week. Lows will be slightly above normal in the mid 70s inland and upper 70s at the coast.

AVIATION /06Z FRIDAY THROUGH 06Z SATURDAY/

Multilayered clouds expected over the region through the early morning with only a low chance, near or below 20 percent, for a shower nearing SGJ, CRG, and SSI toward sunrise. As deep moisture rotates into the region from the east starting after 12z, enhanced chances of showers and storms can be expected today. First good chances for showers and storms will be for the coastal TAFs starting at about 12z/13z, and then after 16z/17z for GNV. With how much moisture is moving in, we can expected some MVFR cigs and possibly IFR SHRA/TSRA during the day, though exact timing is tricky. Light and variable Sfc winds near 5 kt or less tonight will become easterly up to 10-15 kt during the daytime. Anticipate gusty winds of about 25-30 kt in convection.

MARINE

High pressure ridge extending from over Bermuda westward to the southeast states will continue through the weekend. A trough of low pressure will move into the area today, which will increase east to southeast winds and build seas. Small Craft Exercise Caution headlines are in effect for parts of the Florida waters. In addition, numerous showers and thunderstorms are expected at times over the area waters today through Saturday. Some of the thunderstorms may be strong. The high pressure ridge will build back over the area waters early next week resulting in a weaker wind flow.

Rip Currents: Winds are becoming more easterly and seas at area buoys have risen slightly compared to yesterday to about 2 ft. An increase in wind waves and breezier onshore flow will put the risk solidly in moderate to high today. By Saturday, we will likely be moderate to high risk based on current forecasts. The risk may be a touch lower risk on Sunday, but still close to the moderate to high category. In any event, swimming conditions will deteriorate today through the weekend.

FIRE WEATHER

Prevailing easterly winds today with morning showers and isolated coastal storms shifting inland through the afternoon and early evening expanding in coverage especially across northeast Florida. Breezy southeast winds will impact coastal areas Friday. An upper disturbance and surface trough moving into the area from the Atlantic will increase chances for showers and thunderstorms this weekend with light southeasterly winds inland Saturday turning breezy and more easterly behind the Atlantic seabreeze as it shifts well west of I-95. By Sunday, light southerly winds Sunday with the trough lifting north of the area with a weaker Atlantic seabreeze closer to the coast turning winds southeasterly.

Daytime dispersions will be generally good today then generally fair Saturday and Sunday with increased clouds and rainfall across the area. Humidity will remain above critical values into the weekend.

Fog Potential: Significant fog development is not expected, with shallow, patchy fog late overnight limited to areas that receive locally heavy rainfall.

EQUIPMENT

KVAX 88D radar is down due to bad elevation encoder and will be unavailable until further notice until the part arrives and repair is made.

PRELIMINARY POINT TEMPS/POPS

AMG 92 73 90 73 / 30 10 60 30 SSI 88 78 88 78 / 40 70 80 30 JAX 89 74 89 74 / 60 30 80 10 SGJ 88 77 88 75 / 70 30 70 20 GNV 89 73 90 73 / 70 20 70 30 OCF 89 74 90 74 / 70 20 80 30

JAX WATCHES/WARNINGS/ADVISORIES

FL...High Risk for Rip Currents from 8 AM EDT this morning through late Saturday night for FLZ124-125-138-233-333. GA...None. MARINE...None.