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

- Monday: Red Flag Warning for portions of Northeast FL

- Cold Blast Returns Tonight with Nightly Freezes through Wed. Tonight: Dangerous Wind Chills in the low 20s Areawide + Freeze Warning. Monday Night: Freeze Warning & dangerously low wind chills. Tuesday Night: Light Inland Freeze & Frost Warning through Monday Afternoon

NEAR TERM /THROUGH TONIGHT/

WEATHER CONCERNS PERIOD: - Red Flag Warning (Critical Fire Weather) today for portions of northeast Florida - Freeze and dangerously low wind chill values area-wide tonight

After a cold start to the morning, high temperatures will be about 15-20 degrees below normal, only reaching the upper 40s to mid 50s as breezy northwesterly winds continue. Wind gusts will pick up after sunrise again, peaking around 30 mph in the afternoon, these winds coupled with low relative humidity values will create dangerous fire weather conditions again. A Red Flag Warning is now in effect for portions of northeast Florida.

Cold air advection and clear skies will allow for freezing temperatures areawide Monday night into Tuesday morning, with some inland locations seeing hard freeze conditions. Winds will calm Monday night, but dangerously cold wind chill values in the 20s areawide will return Monday night prompting a Cold Weather Advisory for most of northeast Florida. Given calmer winds but dry conditions, patchy frost may develop over inland areas.

SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/

MAIN WEATHER CONCERNS (Tuesday - Wednesday Night: - Critically Low Humidity Values at Inland Locations on Tuesday

- Light Freeze Inland with Widespread Frost on Tuesday Night

- Warming Trend Begins on Wednesday

Deep troughing will depart the southeastern seaboard early on Tuesday, leaving behind a dry northwesterly flow in its wake through early Wednesday morning. Meanwhile, Arctic high pressure will gradually weaken as it settles over the FL peninsula on Tuesday afternoon and night. Following a very cold start to the day, sunny skies and a very dry air mass will allow highs to rebound to the 55- 60 degree range on Tuesday afternoon. Dewpoints remaining in the teens and 20s will result in long durations of critically low humidity values at all inland locations, while decreasing surface winds preclude Red Flag conditions across our region.

Although cirrus cloud cover will begin to enter our area from the northwest on Tuesday evening, decoupling winds early in the evening will create radiational cooling, with a light freeze possible at inland locations, accompanied by widespread frost, as lows fall to the lower 30s. Light freeze potential should be greater for inland north central FL, closer to the decaying Arctic surface ridge. Patchy to areas of frost may extend to coastal locations, where lows will fall to the mid and upper 30s.

Flow aloft across our region will become zonal by Wednesday afternoon and night, downstream of a trough that will be digging southeastward from the Pacific northwest through the Rockies, with this feature quickly entering the southern Plains states by early Thursday. High pressure will shift eastward off the southeast FL coast by Wednesday afternoon, with breezy southwesterly winds and rising heights boosting highs to the upper 60s and lower 70s region- wide, which is near late February climatology. Mid and high altitude cloud cover will continue to gradually increase across our area through Wednesday night, with warm air advection keeping lows in the 40s almost area-wide.

LONG TERM /THURSDAY THROUGH SUNDAY/

Main Hazards During the Long Term Period: - Beneficial Showers and Possibly a Few Storms Late in the Week through the Upcoming Weekend

Flow aloft across the Deep South will transition to southwesterly on Thursday downstream of a trough and associated frontal boundary that will will be diving southeastward through the Ozarks and the lower Mississippi Valley. Mainly mid and high altitude cloud cover will continue to gradually thicken across our area, but a dry low level air mass will likely linger across northeast and north central FL through Thursday evening. Shower chances will gradually increase downstream of the approaching frontal boundary towards sunset on Thursday evening for locations west of Waycross in southeast GA and for areas northwest of Live Oak in the Suwannee Valley. Our local pressure gradient will also tighten on Thursday, creating breezy south-southwesterly winds that may increase the wildfire potential given ongoing drought conditions. Highs on Thursday afternoon will climb above late February climatology, with mid to upper 70s at most inland locations, except lower 80s for portions of north central FL.

Model blends currently indicate scattered to numerous showers traversing our region from Thursday night through Friday night as the frontal boundary slows its southeastward momentum. PWATs climbing above 1.5 inches should allow enough instability to develop ahead of the front to possibly develop a few thunderstorms, mainly for locations south of Interstate 10. Beneficial rainfall amounts are expected area-wide during this time frame, and the frontal boundary may stall over north central FL on Friday night and Saturday as troughing pivots across the southeastern states. The aforementioned trough could also develop a weak wave of surface low pressure across our area on Saturday, keeping at least scattered showers and thunderstorms in the forecast into Saturday evening.

Forecast confidence decreases late in the weekend, with model blends indicating a light onshore wind regime that may keep at least scattered chances for showers into early next week. Above normal warmth will prevail despite expected cloud cover, with highs generally in the 70s inland, possibly reaching the lower 80s for north central FL, and lows remaining in the 50s. Onshore winds and cool shelf waters may keep coastal highs in the mid to upper 60s, especially for southeast GA.

AVIATION /06Z MONDAY THROUGH 06Z TUESDAY/

VFR conditions and gusty northwesterly winds continue through the TAF period. Gusts will be on and off through the night, and more frequent after daybreak.

MARINE

Frequent gusts to gale force will continue through Monday afternoon between a strong surface low pressure well northeast of the region and high pressure to the west. Winds and seas begin to subside Monday night into Tuesday as the surface high builds eastward across the Gulf Coast states. The high will extend across south Florida Wednesday as the next front approaches from the west into Thursday. A low chance of thunderstorms returns by Friday as the front slowly shifts south across the local waters, likely stalling across the Florida peninsula into the weekend.

Rip Currents: Moderate rip current risk today for the northeast Florida and southeast Georgia beaches.

FIRE WEATHER

RED FLAG CONDITIONS THIS AFTERNOON FOR NORTH CENTRAL AND PORTIONS - Of Northeast Florida

- Elevated Fire Danger Elsewhere This Afternoon

- Pockets Of High Daytime Dispersion Values This Afternoon

ELEVATED NIGHTTIME DISPERSION VALUES FOR COASTAL NORTHEAST - Florida Tonight

- High Daytime Dispersion Values Wednesday And Thursday

A Red Flag Warning is in effect this afternoon for all of north central Florida and for portions of northeast Florida, due to critically low humidity values, northwesterly winds sustained at 15- 20 mph, and ongoing extreme drought conditions. An Elevated Fire Danger will exist elsewhere today due to gusty northwesterly winds, near critical humidity values, and ongoing severe to extreme drought conditions. Strong transport winds will create pockets of high daytime dispersion values, with good to marginally high values forecast elsewhere. Breezy northwesterly transport winds will keep nighttime dispersion values elevated for coastal northeast Florida tonight.

Diminishing northwesterly surface and transport winds on Tuesday morning will shift to westerly during the afternoon hours. Long durations of critically low humidity values are expected at all inland locations. Surface and transport winds will then shift to southwesterly on Wednesday, with increasing speeds resulting in high daytime dispersion values at most inland locations, with good values expected for coastal locations. Strong south-southwesterly surface and transport winds will prevail on Thursday, creating high daytime dispersion values at most locations. Beneficial rainfall is possible late this week, with a few thunderstorms possible south of Interstate 10 on Friday afternoon.

FOG POTENTIAL AND OTHER REMARKS: A light freeze is expected early on Monday morning for inland locations north of Interstate 10. Widespread freezing temperatures are forecast late tonight and early Tuesday morning, with a hard freeze likely for inland southeast Georgia, the Suwannee Valley, and portions of inland northeast and north central Florida. Patchy frost formation will be possible late tonight and early Tuesday morning area-wide. A light freeze and widespread frost are then expected at most inland locations late on Tuesday night and early Wednesday morning, with patchy to areas of frost possibly extending to coastal locations. . Widespread frost and a possible light freeze are forecast on Tuesday night.

PRELIMINARY POINT TEMPS/POPS

AMG 48 25 55 33 / 0 0 0 0 SSI 50 30 55 37 / 0 0 0 0 JAX 52 28 59 33 / 0 0 0 0 SGJ 54 31 58 37 / 0 0 0 0 GNV 54 27 59 33 / 0 0 0 0 OCF 55 26 59 31 / 0 0 0 0

JAX WATCHES/WARNINGS/ADVISORIES

FL...Cold Weather Advisory from 4 AM to 9 AM EST this morning for FLZ021-023-024-030-031-035-038-120-124-125-132-136>138- 140-220-225-232-233-236-237-240-322-325-333-340-422-425- 433-522-533-633. Cold Weather Advisory from 2 AM to 9 AM EST Tuesday for FLZ021- 023-024-030-031-035-038-120-124-125-132-136>138-140-220- 225-232-233-236-237-240-322-325-333-340-422-425-433-522- 533-633. Freeze Warning from midnight tonight to 9 AM EST Tuesday for FLZ021-023-024-030-031-035-038-120-124-125-132-136>138- 140-220-225-232-233-236-237-240-322-325-333-340-422-425- 433-522-533-633. Freeze Warning until 9 AM EST this morning for FLZ023-024-120- 220-322. Red Flag Warning from 1 PM this afternoon to 6 PM EST this evening for FLZ023-024-030-031-035-038-132-136>138-140- 232-236-237-240-333-340-425-433-533-633. GA...Cold Weather Advisory from 4 AM to 9 AM EST this morning for GAZ132>136-149-151>154-162-163-165-166-250-264-350-364. Freeze Warning from midnight tonight to 9 AM EST Tuesday for GAZ132>136-149-151>154-162-163-165-166-250-264-350-364. Freeze Warning until 9 AM EST this morning for GAZ132>136-149- 151>154-162-163-165-166-250-264-350-364. MARINE...Gale Warning until 10 AM EST this morning for AMZ450-452-454- 470-472-474.