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

- Red Flag Warning this Afternoon for North Central & Northeast FL. Elevated Wildfire Danger Elsewhere this Afternoon. Long Durations of Critically Low Humidity Values at All Inland Locations Tuesday

- Tonight: Freeze Warnings Area-Wide, with Hard Freezes for Inland Locations West of I-95. Cold Weather Advisories Tonight for Northeast & North Central FL. Tuesday Night: Light Freeze Inland & Widespread Frost w/ Patchy Frost at Coastal Locations

- Small Craft Advisory through early Tuesday Morning

- Beneficial Rainfall and Isolated Thunderstorms Expected Thursday Night & Friday

MONDAY MORNING UPDATE

KEY CHANGES AND UPDATE MESSAGES: - Cold Weather Advisory and Freeze Warning for this morning have been cancelled - Red Flag Warning has been expanded to include all of northeast FL this afternoon and evening, and could be expanded into parts of southeast GA later today depending on trends and observations - Gale Warning over area waters has been replaced with a Small Craft Advisory through tonight

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 Surface ridging will strengthen along the Mid-Atlantic coast as the frontal boundary potentially stalls over north central FL, resulting in an onshore wind pattern. Highs will likely remain in the 70s for most locations on Saturday, with lower 80s possible for north central FL and upper 60s for coastal southeast GA. Lows should remain in the 50s throughout our area on Saturday night.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 /12Z MONDAY THROUGH 12Z TUESDAY/

VFR conditions and gusty northwesterly winds continue through around 23Z this evening. Sustained surface speeds of 15-20 knots and frequent gusts of 25-30 knots are expected, especially after 14Z. Northwesterly surface winds will then diminish to 5-10 knots at the regional terminals after 00Z this evening.

MARINE

Intense low pressure situated off the Mid-Atlantic coast early this morning will lift northeast through tonight, reaching Atlantic Canada by early Tuesday morning. Meanwhile, Arctic high pressure building southeastward from the Upper Midwest will gradually weaken as it settles over the Florida panhandle by sunrise on Tuesday. Small Craft Advisory conditions expected rest of today and tonight before winds and seas gradually subside on Tuesday as weakening high pressure shifts southeastward towards the Florida peninsula. This high pressure center will then shift offshore of the southeast Florida coast by Wednesday afternoon, with breezy south- southwesterly winds prevailing across our local waters through Friday. Showers and possibly a few thunderstorms will overspread our local waters on Friday and Friday night as a frontal boundary stalls over our area. A wave of weak low pressure potentially developing along this front could keep shower chances in place for at least a portion of the upcoming 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.

CLIMATE

Record Low Temperatures on Tuesday at our designated climate sites:

Tues, February 24: KJAX: 27/1989 KCRG: 27/1989 KGNV: 25/1989 KAMG: 24/1964

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...Red Flag Warning from 1 PM this afternoon to 6 PM EST this evening 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. 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. GA...Freeze Warning from midnight tonight to 9 AM EST Tuesday for GAZ132>136-149-151>154-162-163-165-166-250-264-350-364. MARINE...Small Craft Advisory until 7 AM EST Tuesday for AMZ450-452-454- 470-472-474.