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 Of Rip Currents through Monday

- Thunderstorms this Week - Mainly Afternoon & Evening. Today: Isolated Strong Storms near I-75 Corridor Late Afternoon & Evening. Tue & Wed: Inland Storms. Thu-Sat: Better storm chances focus toward I-95 Corridor

NEAR TERM /THROUGH TONIGHT/

Main Highlights This Period:

- High Risk for Rip Currents through Monday - Isolated Severe Storm Risk near I-75 late afternoon & evening

A very unstable airmass was developing across the local forecast area early this afternoon with surface based CAPEs over 3k J/kg with temps in the upper 80s to near 90 inland and juicy dew pts in the lower 70s. Radar showed a few 'seeding' showers breaking out ahead of the east coast sea breeze across Flagler, Putnam, Marion and Duval counties. With further heating and sea and river breeze boundaries developing, diurnally enhanced convection will continue to erupt through the afternoon and expand in coverage between the Highway 301 and Interstate 75 corridors. By late afternoon into the early evening, sea breeze and boundary collisions are still on track to merge near the Interstate 75 corridor where the best potential for strong to pulse severe storms will focus. Mean layer 1000-700 mb ESE steering flow near 10 kts will propagate cells toward the WNW, but upper level NW anvil level flow will push some lingering stratiform and lightning risk back toward the ESE as surface based storms depart to the west of the region through 10 pm.

The 12z JAX RAOB displayed a more unstable airmass compared to yesterday with a weakening and lifting low level inversion. Very steep mid level lapse rates (7.5 C/km) were noted between 700-500 mb with below normal 500 mb temps of -11.6 degC and stronger NW anvil level winds. There was also a notable layer of dry mid level air. All of these convective ingredients support an increased risk of isolated strong to pulse severe storms this afternoon where boundary mergers collide, especially for locations west of Highway 301 and toward the I-75 corridor between the 5 pm and 8 pm time frame. Thunderstorm hazards will include gusty wet downbursts of 40-60 mph and small hail, as well as localized heavy rainfall and frequent lightning. With storm motion of only near 10 kts and deep layer moisture over the 75th percentile of 1.53" for locations near and west of Highway 301, localized, temporary flooding could occur this evening across parts of the Suwannee River Valley, with localized high end values of 2-3 inches.

Rainfall tapers off by 10 pm as drier air invades from the east with precipitable water content falling below 1 inch into Monday morning. With inland rain this evening, clearing skies overnight and decoupled winds, included patchy ground fog toward daybreak for much of the I-75 corridor northward into SE GA, generally west of Waycross as low temperatures fall into the mid to upper 60s inland to low 70s coast thanks to the drier air.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/

Main Highlights This Period:

- Showers and storms development limited on Monday. Afternoon thunderstorms return on Tuesday along the sea breeze.

- Rip currents at area beaches will be a concern; High risk likely through the first half of the upcoming week.

Drier air in place on Monday will limit convection, leaving mostly sunny skies and warm temperatures. An onshore breeze will keep east coast locations in the 80s whereas most inland spots will rise into the low 90s. The stronger easterly winds may bring a few stray showers onshore Monday afternoon and into north central Florida, but overall it will be a dry day.

Tuesday, PWATs begin to increase with steering flow coming off the Atlantic, paving the way for daily afternoon showers and storms. Convection will mainly be limited to northeast FL on Tuesday, particularly near the I-75 corridor where sea breezes merge, with similar temperatures to Monday as the onshore breeze continues.

LONG TERM /WEDNESDAY THROUGH SATURDAY/

Weather Concerns this Period:

- Daily afternoon thunderstorms; best coverage and strongest storms expected along the sea breeze mergers

- Rip currents at area beaches continue to be of concern

Precipitation chances will increase in coverage gradually each day Wednesday onward as onshore winds continue and a front begins to sink southward and stall over northern Georgia late this week. Midweek, the Atlantic sea breeze will push inland, sparking up convection mainly west of I-95 each afternoon as it interacts with the Gulf sea breeze. By the end of the week into the weekend, steering flow is expected to become more southerly, allowing the two sea breezes to meet in a more central location, and increasing precipitation chances overall this weekend.

Overall, temperatures each day will be a little above normal, in the lower to mid 90s inland, and a little cooler near the Atlantic coast in the mid to upper 80s.

AVIATION /18Z SUNDAY THROUGH 18Z MONDAY/

Sea breeze showers and storms will continue to blossom near and inland of the inland progressing east coast sea breeze through 9 pm, with the best chances of TSRA impacting VQQ now through 20z and GNV from roughly 18-01z. Breezy ESE winds will trail the sea breeze with dry conditions at other terminals after 19z with sustained speeds 11- 14 kts and gusts of 20-25 kts at times. Winds relax into the evening as debris clouds fade, with dry conditions by 02z. After 06z, fog potential increases at VQQ and especially GNV where rainfall is most likely to occur later today. At this time, included 6 SM at GNV and 4 SM at VQQ after 08z through 12z. After 12z, VFR conditions under ESE winds 5-10 kts and dry weather.

MARINE

The Bermuda ridge will dominant through the week with a ridge axis extending just north of the local waters. This pattern will bring persistent east to southeast winds, with local wind surges each afternoon and evening trailing the inland progressing east coast sea breeze. Morning and midday showers and isolated coastal storms will shift inland by mid-afternoon with generally clearing skies across the local waters late afternoon into the evening.

Rip Currents:

A high rip current risk continues for all local beaches through at least Monday due to persistent onshore winds. An elevated risk will continue through the end of the week due to prevailing ESE winds.

FIRE WEATHER

- Patchy High Dispersions Into Midweek

The combination of deep mixing and sufficient southeasterly transport winds will generate generally good to high dispersions inland each afternoon heading into midweek. Patchy high dispersion will be present over inland locations on Monday and Tuesday. MinRH will be unconcerning this week, with slightly lower values inland on Monday, however they will be above critical values. Moisture then steadily increases each day, with thunderstorms possible each afternoon and evening, mainly for inland northeast FL through Thursday, then area-wide Friday through next weekend.

FOG POTENTIAL AND OTHER REMARKS: Isolated thunderstorms each day Tuesday onward. Patchy fog possible early Monday morning inland.

PRELIMINARY POINT TEMPS/POPS

AMG 90 65 89 63 / 60 40 0 0 SSI 82 72 83 73 / 10 0 0 0 JAX 88 68 86 70 / 20 0 0 0 SGJ 85 72 86 73 / 10 0 0 10 GNV 91 68 91 69 / 60 40 10 0 OCF 91 68 91 70 / 50 40 10 0

JAX WATCHES/WARNINGS/ADVISORIES

FL...High Risk for Rip Currents through late Monday night for FLZ124-125- 138-233-333. GA...High Risk for Rip Currents through late Monday night for GAZ154-166. MARINE...None.