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

- Isolated TStorms Possible Along & North of I-10 on Fri & Fri Night

- Periods of Heavy Rainfall Expected Across Southeast GA Sat & Sat Night

- Periods of Heavy Rainfall Shift Southward Across Northeast FL Late Sat. Isolated TStorms Possible Area-Wide. Severe Weather Not Anticipated.

- Severe to Extreme Drought Continues for Inland Areas

- Light Freezes & Frost Possible Inland on Mon & Tues Nights Next Week

- Moderate Rip Current Risk Continues at Area Beaches

UPDATE

Forecast on track as light to moderate rainfall has overspread most of SE GA this evening, while a few light showers and/or sprinkles will be possible along the I-10 corridor of North FL, while the rest of NE FL remains mostly dry through the overnight hours. Temps at least 10-15 degrees milder last night due to the increased cloud cover and winds slowly shifting towards the south towards morning. Lows will generally remain steady or only slowly fall into the mid/upper 40s across SE GA, with lower/middle 50s across NE FL.

NEAR TERM /UNTIL 6 AM FRIDAY MORNING/

Afternoon surface analysis depicts developing weak low pressure (1014 millibars) situated along a frontal system near the northern Gulf coast. Meanwhile, an arctic cold front was pushing southeastward across New England and the Tennessee and Ohio Valleys, with stronger high pressure (1033 millibars) building over the Upper Midwest in the wake of this front. Aloft...fast zonal flow prevails locally, as our region remains situated between ridging over Cuba and the Bahamas and troughing that was being deflected eastward across the Upper Midwest and the Plains states.

Weak shortwave energy embedded within the fast west-southwesterly flow pattern across the Deep South was inducing strengthening isentropic lift / overrunning across southeastern GA, where light showers and sprinkles were quickly moving northeastward across inland locations. Temperatures remain in the 40s at 18Z across inland southeast GA, where thick mid and high altitude cloudiness was locked in place. Temperatures remain in the 50s across coastal southeast GA and along the Interstate 10 corridor, with breaks in this cloud cover have allowed temperatures to climb into the 60s. Fair skies prevail across most of north central FL, where temperatures have climbed to the lower 70s as of 18Z. Dewpoints ranged from the 40s for locations along and north of I-10 and 50-55 elsewhere.

Brisk west-southwesterly flow aloft will continue across our region into the weekend as troughing continues to dig to the northwest of our region and ridging prevails over the Bahamas and the Greater Antilles. Shortwave energy embedded within this fast, mostly zonal flow pattern locally will continue to push across southeast GA through around midnight, assisting in strengthening the overrunning / isentropic lift pattern. Chances for measurable light rainfall will gradually increase late this afternoon through this evening across southeast GA, with chances for measurable rainfall extending to northern portions of the Suwannee Valley.

Dry weather is expected elsewhere through tonight, with less cloud cover over north central FL possibly allowing some patchy fog or low cloud development towards sunrise. Low level flow will veer overnight as weak low pressure glides eastward along the FL panhandle coast, with this storm system's warm front lifting towards north central FL by sunrise on Friday. Developing warm air advection will keep lows in the 50s across coastal southeast GA and all of northeast and north central FL, with near steady temperatures in the upper 40s expected for most of inland southeast GA.

SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY NIGHT/

Friday, mid/upper level WSW flow will be over the region downstream of broad troughing between the intermountain west and the MS river valley extending southwestward across the Rio Grande Valley into a formerly cutoff low near the Baja peninsula while ridging aloft remains southeast of the region over the southern Bahamas and the Turks and Caicos. At the surface, a wavy frontal boundary will extend eastward along the FL/GA state line with low pressure along the FL panhandle Gulf coast. Through Friday night, the northern portion of the trough will shift eastward across the Great Lakes and OH Valley with a stream of shortwave energy traversing across the deep south and the Gulf coast ahead of the broad troughing. This will push the wave of low pressure ENE across the area in the afternoon and offshore into the Atlantic waters Friday night with rounds of heavier showers spreading across Southeast GA and the northern Suwannee Valley. An embedded isolated T'storm is possible through Friday night, but not expecting severe weather threats.

Highs Friday will be warm south of the front across NE FL with upper 70s to around 80 over north central FL/southern St Johns river basin, but remain cool in the upper 50s to low 60s north of Waycross. Lows on Saturday will start of around 50F over SE GA and be milder over NE FL in the upper 50s inland to the lower 60s along the coast and southward to Ocala.

Saturday, another shortwave trough impulse associated with northern portion of the larger trough will move through the TN Valley and help spur another wave of low pressure developing over southern GA and moving eastward. Rounds of heavier showers will develop in the afternoon and push into Northeast FL areas from the Suwannee Valley by the mid to late afternoon and to the first coast around sunset. An isolated T'storm is possible south of I-10, but instability will be lacking to produce strong to severe Tstorms. Frontal boundary will sink south into NE FL by Saturday night with light westerly winds becoming northwesterly, then north to northeasterly behind the front as it stalls near north central FL. Heavy showers will persist overnight into early Sunday as the low moves over the area, then off the coast with another low developing to the west.

Highs Saturday will be near normal along the I-10 corridor in the upper 60s, above normal southward into north central FL in the mid to upper 70s and below normal into SE GA with upper 50s north of Waycross and low 60s along the coast.

Sunday, another, more vigorous shortwave with the northern portion of the trough will phase with the southern portion and push eastward from the southern/central plains across the MS valley towards the southern and central Appalachians. This will bring additional lift/instability over the region with final wave of low pressure developing over the NE Gulf and pushing east across NE FL and into the Atlantic waters by the mid to late afternoon. This will feature new rounds of heavy rainfall spreading back across NE FL and extending numerous showers back north into SE GA. Embedded isolated T'storm activity will help produce heavier rainfall rates as PWATs (Precipitable water levels) exceed the 90th percentile and near daily max values around 1.80 inches. While much of this rain will be beneficial, rainfall rates of 2-3 inches per hour may produce isolated instances of flash flooding in low lying and poor drainage areas such as within urban areas. Severe T'storm potential will be very low given weak low level instability with storms more likely elevated.

Widespread rainfall totals of 2-4 inches will be expected over SE GA into the Suwannee Valley with 1-3 inches along the coast. There is high end potential for greater than 6 inches of rainfall over western portions of SE GA/northern Suwannee Valley through Sunday night.

Highs Sunday stay below normal north of I-10 into 60-65F degree range with upper 60s just south of I-10 into Jacksonville and warm above normal into the low to mid 70s over southern zones. Lows Sunday will be similar to Saturday around 50F over SE GA and mid 50s over inland NE FL to upper 50s to near 60F over the NE FL coast.

LONG TERM /MONDAY THROUGH THURSDAY/

Monday, large trough will swing east of the eastern seaboard with ridging briefly building across the MS valley with WNW flow over the region. A cold and dry airmass will filter into the area as high pressure over the Midwest builds eastward. Despite cloudy skies turning mostly sunny skies by afternoon, brisk northerly to northwest winds will keep highs below normal with upper 50s and lower 60s over SE GA, and mid 60s for NE FL with upper 60s over north central FL. Lows will fall Monday night to the mid 30s over inland SE GA with potential for frost with low 40s over inland NE FL/SE GA coast. Lows will warm towards the NE FL coast as the northerly wind fetch catches warmer temperatures from the local waters with low 50s along the NE FL coast. Tuesday through Thursday, high pressure will settle over the region with a light freeze and frost event inland Wednesday morning. Skies will be mostly sunny with light west winds becoming southwesterly Thursday under high cirrus aloft. Highs below normal on Tuesday gradually warm each day towards normal values by Thursday. Another cold front will approach Thursday with a few showers, but overall not expecting much rainfall.

AVIATION /00Z FRIDAY THROUGH 00Z SATURDAY/

Light rainfall has overspread all of SE GA early this evening and will impact the SSI terminal with lower VFR CIGS and 6SM vsbys in SHRA at times through 06Z, otherwise mid cloud decks in the 7000- 10000ft range will push across NE FL terminals through 06Z with a few sprinkles (VCSH) at JAX/VQQ/CRG while remaining dry at GNV/SGJ with light and variable winds around 5 knots through tonight, but likely enough wind to prevent any fog fog formation. SW winds increase to 10-12 knots with gusts to 15-18 knots Friday morning by 15Z onward with VFR conds remaining at NE FL terminals, while MVFR CIGS set up at SSI. Wind shift/frontal boundary with shower activity will push southward across the region Friday afternoon, reaching SSI by 18Z with lower MVFR CIGS and NW winds at 10G15 knots, then LIFR by 21Z time frame. The MVFR CIGS/shower activity and wind shift to NW reaches JAX/VQQ/CRG by 21-22Z and SGJ/GNV right at the end of the TAF period and have tweaked TAF forecast to show this downward trend in CIGS/VSBYS.

MARINE

Weak low pressure organizing along the northern Gulf coast this afternoon will lift a warm front northeastward across our local waters on Friday, accompanied by showers and possibly an isolated thunderstorm. Weak low pressure will move northeastward across southeastern Georgia on Friday afternoon, with this storm system's cold front then crossing our local waters on Friday night and Saturday morning. A wave of low pressure will then develop along this front just south of the northeast Florida waters on Saturday night, with widespread rainfall and a few embedded thunderstorms likely across our local waters through Sunday. Low pressure will then strengthen as it moves offshore on Sunday night and Monday, resulting in strengthening north northwesterly winds as rainfall ends, with Small Craft Advisory conditions possible from Monday through early Tuesday.

Rip Currents: SE GA Moderate Friday NE FL Moderate Friday

FIRE WEATHER

LOW DAYTIME DISPERSIONS AREA WIDE TODAY... LOW DAYTIME DISPERSIONS SE GA SATURDAY AND NORTH OF I-10 ON SUNDAY...

Light northwesterly to northerly winds surface and transport winds 5- 10 mph will create poor dispersion values today across the area as high pressure exits slowly to the east. Light scattered showers will spread east over Southeast GA areas into northern Suwannee Valley through tonight as a warm front lifts northward into the area from the south. Multiple rounds of rainfall are expected Friday through the rest of the weekend ahead of an approaching cold front that will move through Sunday night. The showers will be heaviest Friday into Friday night over Southeast GA into the Suwannee Valley with the axis of heavier showers moving into Northeast FL late Saturday into much of Sunday before ending by Sunday Evening. Isolated thunderstorms will be embedded with the heavier showers as well, but no severe storms are expected.

Breezy winds from the south to southwest will prevail south of the front over Northeast FL 15-20 mph with gusts 25-30, but low clouds and low mixing heights will limit dispersions to fair to good range while light winds/low clouds will create low daytime dispersions. As the front sinks south of the FL/GA state line on Saturday, light northerly winds 5-10 mph and cloud cover will promote low daytime dispersions north of I-10

FOG POTENTIAL AND OTHER REMARKS: Significant fog is not expected over the next few days. Heavy rainfall will produce rainfall totals of 2-4 inches for most locations with the highest amounts over western Southeast GA locations along/near US441 where locally higher totals may exceed over 6 inches.

PRELIMINARY POINT TEMPS/POPS

AMG 45 59 49 59 / 90 100 70 90 SSI 53 69 52 63 / 50 70 50 70 JAX 52 78 56 69 / 20 50 30 60 SGJ 57 79 60 72 / 10 10 30 40 GNV 54 79 61 74 / 10 20 30 60 OCF 55 80 63 77 / 10 20 30 50

JAX WATCHES/WARNINGS/ADVISORIES

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