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

- Small Craft Advisory Conditions Thursday & Thursday Night

- Freeze Watch Late Thursday Night & Early Friday Morning. Areas Impacted: Southeast GA, Inland Portions of Northeast & North Central FL. Widespread Frost Inland & Areas of Frost Extending to Coastal Locations

UPDATE

Slight tweaks to the precipitation forecast made this evening, as light showers move through southeast Georgia and the Suwannee Valley. As the front moves through overnight, winds will be too elevated to support fog formation and heavy cloud cover will help keep temperatures above freezing. A chillier day is forecast for Thursday following the frontal passage, with gusty northwesterly winds.

NEAR TERM /UNTIL 6 AM THURSDAY MORNING/

A consolidating area of low pressure will continue to gather to the north this evening, accelerating a cold front through the region tonight. A narrow band of low-grade Gulf moisture pooling ahead of the front in addition to an intensifying jet streak, will promote high chances (70-90%) for rain across the region this evening and overnight. Given the lack of appreciable moisture or instability, period of light stratiform rain is expected overnight as the front passes and exits offshore after sunrise Thursday.

Total rainfall amounts will be meager but the regions with better moisture and forcing across SE GA and the Suwannee Valley may total up to 0.50-0.75" which will be beneficial and slow any worsening drought conditions at least temporarily. For areas, where brush fires are breaking out and burning this will also help combat that activity and "clean" the smoke and haze out of the air.

Otherwise for tonight, breezy southwesterly winds will settle after sunset with temperatures warming a bit more tonight with lows in the upper 30s to low/mid 40s. Don't anticipate much in the way of any fog development given the continued light winds this evening and tonight.

SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/

Deep troughing will pivot across our region on Thursday, pushing its associated cold front across coastal northeast and north central FL around or shortly after sunrise. Lingering showers trailing this frontal boundary should move offshore during the early to mid morning hours. Consolidating and gradually strengthening low pressure moving slowly eastward offshore of the southeastern seaboard will create strengthening northwesterly winds during the morning hours, with moisture wrapping around this feature likely keeping lower stratus clouds lingering through at least the early afternoon hours before clearing from west to east during the late afternoon and evening hours. Strong cold air advection will likely keep highs around 50 for inland southeast GA and the mid to upper 50s elsewhere.

Surface ridging building along the northern Gulf coast will allow our local pressure gradient to gradually loosen as the night progresses, with clearing skies and continuing cold air advection will allow for a light freeze and widespread frost at all inland locations and possibly for coastal southeast GA, with areas of frost possibly extending into coastal northeast FL as well. Lows will generally fall to the upper 20s and lower 30s, except low to mid 30s for coastal northeast FL.

Dry northwesterly flow will continue on Friday as a reinforcing shortwave trough dives southeastward from the Great Lakes region through the Ohio Valley, with this feature then pivoting across the Delmarva region and the Mid-Atlantic coast by Friday evening. This feature will push a reinforcing cold front through the Ohio and Tennessee Valleys by Friday afternoon, with this boundary then entering the southeastern states on Friday night. Our local pressure gradient will tighten further on Friday afternoon downstream of this approaching boundary, with breezy westerly winds, sunshine and a dry air mass allowing highs to rebound to the upper 50s and lower 60s. This tighter gradient will persist on Friday night, with weak warm air advection ahead of the approaching reinforcing front and a west- northwesterly breeze keeping lows generally in the upper 30s and lower 40s, except mid 40s for coastal northeast FL.

LONG TERM /SATURDAY THROUGH WEDNESDAY/

The reinforcing and dry cold front will cross our region on Saturday, with strong high pressure building southeastward from the Great Lakes towards the Ohio Valley shifting our winds from northwesterly to northerly by the afternoon hours, except northeasterly at coastal locations. Flow aloft will become more zonal by the afternoon hours, with slowly rising heights, sunshine, and a persistently dry air mass allow highs to climb closer to early February climatology, with 60s inland and around 60 at coastal locations. Our local pressure gradient will then loosen on Saturday night as another high pressure center takes shape along the northern Gulf coast, with a light freeze and frost possible by early Sunday morning for inland locations along and north of Interstate 10. Lows elsewhere will fall to the mid to upper 30s, except low to mid 40s at coastal locations, where a light northeasterly breeze should continue.

Zonal flow aloft on Sunday will then transition to flat riding across our area early next week, allowing temperatures to moderate to above early February climatology on Monday and Tuesday. Highs on Sunday will climb to the mid and upper 60s, except lower 70s for north central FL. The lingering dry air mass and radiational cooling on Sunday night may again allow for at least patchy frost formation by early Monday morning, especially for inland locations north of I-10, where lows will fall to the mid and upper 30s, while upper 30s and lower 40s prevail elsewhere.

Highs will then reach into the 70s for all inland locations on Monday and Tuesday, with cooler shelf waters keeping coastal highs in the 60s on Monday afternoon and around 70 on Tuesday. Lows will remain in the 40s early next week, except around 50 at coastal locations on Tuesday night. A weakening shortwave trough progressing eastward through the southern branch of the jet stream should approach our region on Wednesday, bringing increasing clouds and possibly a few showers. Long term model blends currently keep dry conditions in place through midweek for our region, with above normal warmth continuing area-wide.

AVIATION /00Z THURSDAY THROUGH 00Z FRIDAY/

Tonight a cold front will bring light rain to terminal airspace in NE FL and SE GA. As it moves southeastward ceilings will trend lower initially toward MVFR this evening then IFR during the predawn hours Thursday. Gradual flight condition improvement to MVFR is expected behind the front Thursday morning as winds veer northwesterly, becoming breezy during the late morning hours with gusts up to 25 knots. By early afternoon, VFR conditions are expected.

MARINE

An approaching cold front will move across the waters late tonight. Gusty northwesterly winds behind the front will lead to a period of Small Craft Advisory conditions Thursday and Thursday night. After a brief lull in the winds Friday morning, another cold front will clip the waters resulting in another uptick in winds to Small Craft Advisory levels through Saturday morning. High pressure building to the north behind the front will shift winds to onshore, out of the northeast, and lower speeds by Saturday afternoon.

Rip Currents: Moderate Risk with long period swells producing surf/breakers in the 2-4 ft range today with a further decrease to around 2 ft surf/breakers on Thursday in the offshore flow which may bring the overall rip current risk to low levels.

FIRE WEATHER

Breezy southwesterly surface and transport winds will combine with near critically low humidity values and ongoing drought conditions to create an elevated fire danger this afternoon for northeast and north central Florida, as well as portions of southeast Georgia, mainly for inland locations south and east of Waycross. Otherwise, beneficial showers will overspread inland southeast Georgia this afternoon and evening, with activity then moving across the rest of our area tonight and early Thursday morning. Surface and transport winds will shift to northwesterly during the predawn hours on Thursday, with strong transport speeds and breezy surface speeds creating high daytime dispersion values during the afternoon hours, especially for locations south of Waycross in southeast Georgia. Breezy northwesterly surface and transport winds on Friday morning will shift to westerly on Friday afternoon, with gradually strengthening transport speeds and breezy surface speeds combining with near critically low humidity values to possibly create an Elevated Fire Danger for most of our area, with high daytime dispersion values forecast nearly-area wide. These conditions may continue into Saturday, as surface and transport winds shift back to northwesterly, with breezy transport speeds forecast.

FOG POTENTIAL AND OTHER REMARKS: A light freeze and widespread frost is expected at most inland locations during the predawn and early morning hours on Friday. A light freeze and frost is possible for inland locations along and north of Interstate 10 late Saturday night and early Sunday morning.

PRELIMINARY POINT TEMPS/POPS

AMG 38 51 29 60 / 90 0 0 0 SSI 44 54 34 59 / 90 10 0 0 JAX 44 57 32 62 / 90 10 0 0 SGJ 48 59 35 61 / 90 30 0 0 GNV 44 57 31 62 / 90 20 0 0 OCF 47 59 30 62 / 90 30 0 0

JAX WATCHES/WARNINGS/ADVISORIES

FL...Freeze Watch from late Thursday night through Friday morning for FLZ021-023-024-030-031-035-120-136-137-140-220-232- 236-237-240-322-340-422-425-522. GA...Freeze Watch from late Thursday night through Friday morning for GAZ132>136-149-151>154-162-163-165-166-250-264-350- 364. MARINE...Small Craft Advisory from 10 AM Thursday to 7 AM EST Friday for AMZ452-454-470-472-474.