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

- Long-Duration Cold Weather Outbreak through the Weekend. Hard Freezes Inland & Light Coastal Freezes Tonight. Additional Light Freezes and Frost Possible Inland on Thurs & Fri Nights. Life- threatening Wind Chills (Single Digits) Possible Sat Night & Early Sun. Protect People, Pets, Plants, and Practice Safe Heating

- Gale Conditions this Weekend Atlantic Coastal Waters

- Saturday Snowfall Potential Decreasing. Probabilities for Minor Impacts (Transportation) of 15-25% Across Southeast GA

UPDATE

Cold conditions and a widespread freeze this morning and will continue today with continental high pressure system situated over the LA and srn MS area with a ridge axis to the north FL. Some decent northwesterly flow just above the surface per sounding (about 20-24 kt) with the parent high to the west.

The 12z JAX sounding showed a surface temp of 27 degrees and dewpoint of 23 deg. Very dry air noted above the surface which suggests we may get a bit drier air than forecast so have shaved off a couple of degrees from the forecast dewpoints today which lower min RH. Forecast highs on track for all zones 50s today. Otherwise, minor adjustments for the sky with periods of mid to high clouds passing over the area in association with a shortwave trough. These clouds should still clear out tonight. Another cold night and have tweaked forecast min temps down slightly based on blend of guidance. Will be upgrading most if not all of the freeze watch to a freeze warning for the update.

On the marine forecast, NW winds at 41008 show 16 kt and guidance also shows potential 15-20 kt over area waters this morning. This is reasonable given the wind on JAX 12z sounding had 24 kt at about 1000 ft. Thus, have extended the exercise caution headline until 11 AM.

NEAR TERM /THROUGH TONIGHT/

Cold and dry weather will prevail through today and tonight with anomalously cold temps aloft. Relative to climate guidance has 850 temps around 3C, which is around the 10th percentile locally.

With the cold and slight northwesterly drainage breeze, current wind chill were measuring at in the low to mid 20s, so elected to issue a short-fused Cold Weather Advisory for the rest of the night. The upper level shortwave will usher clouds in from the west which may lead to some warming which may allow the cold weather advisory to be ended earlier as apparent temps begin to rise. Otherwise, the Freeze Warning will remain in effect through the rest of the morning with temps climbing above freezing between 8-9AM.

For today, high pressure at the surface will be dominant while a weak dry front pushes through this afternoon with the passing upper shortwave. Mostly cloudy skies should begin to clear late in the afternoon in the wake of the shortwave, leading to clear skies tonight. This will set up another night of subfreezing temperatures inland but unlike the last couple of nights, this will be a "light" freeze. Light northwesterly drainage winds may keep frost from becoming widespread tonight but certainly areas of frost are certainly likely given the softening wind.

Temperatures will warm into the low/mid 50s this afternoon in SE GA and into the mid/upper 50s in NE FL. Tonight, lows will fall to the into the upper 20s inland and low/mid 30s closer to the coast. A Freeze Watch remains in effect for tonight and is likely to be bumped to a Warning later today.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/

High pressure ridge will be overhead Thursday, then will build more toward the northeast Thursday night into Friday morning. The region will be in a progressive upper flow with weak disturbances moving through bringing cloud cover. Temperatures will continue below average through Thursday night, but will be near normal on Friday.

An area of low pressure will gather in the central Gulf Friday, and track toward the local area. The low will move east across FL peninsula Friday night bringing cloud cover and rain chances. Temperatures will be below normal.

There is some question, as to whether the precipitation could briefly mix with snow as area further develops off the coast late Friday night. There is a great deal of uncertainty regarding this potential.

LONG TERM /SATURDAY THROUGH TUESDAY/

The low is expected to strengthen and move off to the northeast Saturday and Sunday. The chance for a light wintry mix extends into Saturday, as the low pulls away, but this chance is fairly low.

The cold this period is expected to have the main impact. Highs will largely be limited to the 40s over the weekend, with lows Saturday night in the 17 to 22 range. A hard freeze is expected all the way to the beaches. Due to the proximity of the developing low, winds will also be elevated, pushing wind chills down into the single digits across the forecast area.

It will be a little milder Sunday night, but still in the lower to mid 20s.

High pressure ridging will build from the west Monday, and more overhead on Tuesday. Temperatures will remain below normal Monday and Tuesday, but not as cold as the weekend.

AVIATION /12Z WEDNESDAY THROUGH 12Z THURSDAY/

VFR conditions will prevail through the forecast period. Light NW winds will increase back into the 8-10 knot range after 15Z. Light to calm winds expected tonight. Much of the BKN high clouds are expected to push out of the area by this afternoon or evening at the latest.

MARINE

High pressure located to the northwest of the region will be the prevailing weather feature through Friday, with a cool and dry air mass persisting. A dry front will clip the waters this evening and briefly elevate winds to Exercise Caution Levels through Thursday morning. A Gulf low pressure system is expected to develop and cross Florida and push into the local waters Saturday, then move off to the northeast Sunday. As this low intensifies Saturday, Gale conditions are likely to develop.

Rip Currents: A moderate to low risk today and Thursday. Surf will lower from 2-4 feet today to 1-3 feet by Thursday.

FIRE WEATHER

- Critically Low MinRH Values Area-Wide Today and Thursday, and again over the weekend - Patchy low dispersions inland Thursday - Patchy high dispersions Friday, with areas of high dispersions over the weekend

High pressure will prevail across area through Thursday night. An area of low pressure will affect the region Friday night and Saturday. Below normal temperatures will continue into next week, although Fridays highs may touch seasonal averages.

FOG POTENTIAL AND OTHER REMARKS: Significant fog is not expected this morning or Tonight. Frost potential each night through Thursday night.

CLIMATE

Daily records challenged by the arctic cold air outbreak are below:

Record Low Maximum Temperatures:

Saturday, January 31: JAX 40/1909 CRG 43/1977 GNV 47/1909 AMG 44/1948

Sunday, February 1: JAX 42/1900 CRG 44/1980 GNV 41/1909 AMG 42/1980

Record Low Temperatures:

Sunday, February 1: JAX 24/1977 CRG 29/1977 GNV 25/1977 AMG 22/1977

Monday, February 2:

JAX 23/1979 CRG 27/1980 GNV 25/1980 AMG 19/1951

PRELIMINARY POINT TEMPS/POPS

AMG 53 28 54 29 / 0 0 0 0 SSI 55 34 53 41 / 0 0 0 0 JAX 57 31 59 35 / 0 0 0 0 SGJ 57 36 57 41 / 0 0 0 0 GNV 58 30 62 34 / 0 0 0 0 OCF 58 29 62 34 / 0 0 0 0

JAX WATCHES/WARNINGS/ADVISORIES

FL...Freeze Warning until 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 until 9 AM EST this morning for FLZ021- 023-024-030-031-035-038-120-132-136-137-140-220-225-232- 236-237-240-322-325-340-422-425-433-522-533-633. Freeze Watch from this evening through Thursday morning for FLZ021-023-024-030-031-035-120-136-220-236-322-422-425- 522. Freeze Watch from late tonight through Thursday morning for FLZ038-124-125-132-137-140-225-232-237-240-325-340-433- 533-633. GA...Freeze Warning until 9 AM EST this morning for GAZ132>136-149- 151>154-162-163-165-166-250-264-350-364. Freeze Watch from this evening through Thursday morning for GAZ132>136-149-151>153-162-163-165-250-264-350-364. Freeze Watch from late tonight through Thursday morning for GAZ154-166. MARINE...None.