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

- Cold Weather Outbreak through Tuesday Morning. Cold Weather Advisory Tonight Wind Chills 10-15F SE GA, 15-20F NE FL. Widespread Hard Freeze Tonight lows upper teens inland, low/mid 20s coast. Widespread Freeze Likely Again Monday Night hard freeze inland, light freeze coast

- Small Craft Advisory through this afternoon

NEAR TERM /THROUGH TONIGHT/

Early this morning: Mostly clear and very cold as arctic air mass settles over the region in weakening NW flow. Record cold and hard freeze still expected all areas with Min temps still on track for the upper teens/lower 20s inland to middle 20s along the I-95 corridor, with only upper 20s at Atlantic beachfront locations. Light NW winds around 5 mph will continue to allow for Wind Chills in the 15-25F range and will continue Cold Weather Advisory, although a few colder locations could drop below 15F wind chills for a few pockets of Extreme Cold across inland NE FL, but not enough coverage to upgrade to an Extreme Cold Warning in the short term.

Today: High pressure ridge will settle over the Northern Gulf Coast with an axis across the FL Peninsula which will continue the dry NW flow across the local area. Expect Mostly Sunny skies and just a slight bump upwards in temps into the lower 50s, but still well below expected normal temps in the mid/upper 60s. Much less wind than yesterday, but still some increase to W-NW winds at 10-15 mph with a few peak gusts around 20 mph during the early to mid afternoon hours.

Tonight: High pressure settles directly over the FL Peninsula and despite a few thin high clouds from time to time, expect another widespread Freeze event along with the best chance for widespread Frost due to near calm winds and dew point temps recovering as well. A moderate to hard freeze is expected inland with lows in the mid to upper 20s, and a light freeze expected closer to the Atlantic Coast, generally around 30F along the I-95 corridor and lower 30s for the Atlantic beachfront locations.

SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/

Period begins with zonal flow in the mid levels over our region becoming more west southwesterly as an upstream trough extending southwestward from a potent shortwave centered over Ontario begins to dig southeastward into the southern plains/mid MS river valley. The backing flow aloft in the mid levels will weaken/shift surface high pressure ridge from central FL eastward into the Atlantic waters. Light southwest winds will prevails as the surface high settles just south of our area and extends into the Atlantic with increasing high level clouds as a cold front extending from the TN valley into the lower MS valley approaches from the northwest. With cold air advection over and sunshine filtering through the high cirrus, highs will increase to near normal values in the low/mid 60s over SE GA and the mid 60s over NE FL, but cool around 60 degrees at the beaches.

Tuesday night, not as cold as weak warm air advection ahead of the approaching cold front warms overnight lows to the only the low/mid 40s over SE GA, the NE FL coast and the Suwannee Valley. However, residual surface high pressure remaining across central FL will help provide one more night of radiational cooling over north central FL/southern St Johns river basin where winds will be calm and clear skies will brings lows into the mid 30s with patchy frost.

Wednesday, initial trough will shift east across central appalachians in the morning with an elongated southern stream component of the trough swinging southeast into the deep south and the Carolinas. This will press the cold front across the southeast states and into the FL panhandle and southern GA through the day. Ahead of the cold front, showers will spread eastward across SE GA during the day and onto the FL/GA state line into the Suwannee Valley by mid to late afternoon. While strong shear will be over the area, there will be very little instability available for T'storms as low level winds do not appear strong enough to pump in higher dewpoints before the front arrives. The showers and the cold front will press through into NE FL Wednesday night with winds becoming westerly, then northwesterly by sunrise Thursday as the cold front passes to the south of the area.

Rainfall amounts do not appear to be heavy as the showers and front will be progressive, but a appears there will be enough for a wetting rainfall event for SE GA with less amounts over NE FL.

Highs on Wednesday will be in the low 60s over SE GA and the mid 60s over the Suwannee Valley to the upper 60s to near 70 along the NE FL coast and St Johns river basin. Lows on Wednesday night will be in the low/mid 40s as cooler air filters in late overnight.

LONG TERM /THURSDAY THROUGH SUNDAY/

The period will begin with deep troughing along the eastern third of the nation and deep northwest flow over the region. A cold front exiting the region and high pressure building to the west on Thursday will provide for breezy northwest winds and colder temperatures returning to the area under persistent mid and high level cloud cover until a secondary shortwave shoves in from the northwest and clears the mid level trough axis east of the area. Clear skies Thursday night and cold air advection will support an inland freeze with winds light enough for at least patchy frost.

The high will weaken and shift into the west/central Gulf waters Friday with sunny skies, but below normal highs in the upper 50s to low 60s.

Another dry cold front arrives late Friday night/early Saturday morning that will bring another cold and dry airmass into the area as high pressure builds in from the upper Midwest Saturday and then into the OH and TN valley into Sunday. Frost and a light freeze potential remain in the forecast Sunday morning with onshore winds keeping the beaches above freezing. Highs will trend to near normal by Sunday.

AVIATION /12Z MONDAY THROUGH 12Z TUESDAY/

VFR conditions with generally SKC through the period. West to Northwest 5 knots or less early this morning, increasing back close to 10 knots after 15Z, then becoming near calm or light and variable after sunset (23Z) this evening.

MARINE

Small Craft Advisory conditions this morning, but winds and seas will slowly subside this afternoon through tonight as high pressure builds across the Gulf Coast states. The high builds over the Florida peninsula Tuesday. The next cold front approaches from the west Wednesday, moving across the area waters Wednesday night. Weak high pressure builds into the region, followed by another cold frontal passage on Friday.

Rip Currents: Solid Moderate Risk with lingering swell from departing storm producing surf/breakers in the 4-6 ft range today with a slow decrease to 2-4 ft surf/breakers on Tuesday. Could argue for a High Risk of Rips today if it wasn't for the frigid temps and the offshore flow in place.

FIRE WEATHER

- Critically Low Rh Values Today AREAS OF HIGH DISPERSIONS OVER PORTIONS OF NORTHEAST FLORIDA - Wednesday

Dry conditions expected today as high pressure builds towards the area from the west with light northwest winds 5-10 mph and elevated 10-15 mph over lakes, rivers, immediate coast becoming westerly in the afternoon hours. Min RH values will fall below critical values 20-25 percent. The high will move east over the Florida peninsula Tuesday just south of the area with light southwest winds around 5- 10 mph under increasing high clouds. Min RH values improve to around 30 percent Tuesday.

A cold front will approach Wednesday with numerous showers and a wetting rainfall expected as the cold front shifts southeast through the area. Increasing surface and transport winds well ahead of the front will create areas of high dispersions south of I-10 Wednesday. Dry conditions return to end the week with minRH values approaching near critical values 25-30 percent by Friday.

FOG POTENTIAL AND OTHER REMARKS: Very cold wind chills will be expected into early this morning along with Hard freeze conditions. A light Freeze expected tonight into early Tuesday morning.

CLIMATE

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

Record Low Temperatures:

Monday, February 2:

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

PRELIMINARY POINT TEMPS/POPS

AMG 52 26 62 42 / 0 0 0 10 SSI 50 34 59 43 / 0 0 0 0 JAX 53 28 63 39 / 0 0 0 0 SGJ 52 30 62 40 / 0 0 0 0 GNV 54 28 65 36 / 0 0 0 0 OCF 54 27 65 35 / 0 0 0 0

JAX WATCHES/WARNINGS/ADVISORIES

FL...Cold Weather Advisory until 10 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. Freeze Warning until 10 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. Freeze Warning from 10 PM this evening 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...Cold Weather Advisory until 10 AM EST this morning for GAZ132>136-149-151>154-162-163-165-166-250-264-350-364. Freeze Warning until 10 AM EST this morning for GAZ132>136-149- 151>154-162-163-165-166-250-264-350-364. Freeze Warning from 10 PM this evening to 9 AM EST Tuesday for GAZ132>136-149-151>154-162-163-165-166-250-264-350-364. MARINE...Small Craft Advisory until 10 AM EST this morning for AMZ452- 454. Small Craft Advisory until 7 PM EST this evening for AMZ470- 472-474.