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 Tonight through Tuesday Morning. Extreme Cold Warning Tonight Into Late Sunday Morning with Wind Chills 5-10F. Hard Freeze Sunday Night & Inland Freeze Monday Night with Frost

- Rain & Snow Mix Today Portions of Southeast GA. Winter Weather Advisory for Minor Transportation Impacts. Rain & Snow Wintry Mix - Less than 0.5 snow accumulation

- Gale Warning Late Today through Sunday Frequent Gusts to 45 knots. Lower than normal low tides tonight with strong offshore winds.

- Gusty Winds Today & Tonight Coast & North-Central Florida. Peak gusts 35-45 mph - Secure vulnerable objects

NEAR TERM /THROUGH TONIGHT/

A dynamic and rare winter weather setup continues for the region over the next 24 hours as strong low pressure deepens offshore of the Carolinas. The arctic cold front moved through the area this morning and will see the temperatures falling through the afternoon hours. As the low strengthens offshore, the pressure gradient will tighten and wrap-around moisture will develop over the area. The moisture will support rain and snow mixture this afternoon into late evening as the low level temps will be unusually cold for the area, with the climate percentile for 925-850 mb temps at the 5th percentile or less. The mid/upper level trough will swing through into the evening hours with impressive height falls, and the 500 mb temperature over north half of zones briefly drops to about -31C.

The primary hazard tonight will be the extreme cold tonight and Sunday, with a hard freeze tonight with lows in the upper teens to lower 20s. Very cold wind chills expected and forecast to fall into the single digits of about 5-10 deg range. Record lows are likely tonight/Sunday morning...compared to the cold winter of 1977. See climate section below.

The transition of snow area will be over the northeast zones, with some very light snow accumulations possible up to 0.2 or possibly 0.5 inches. As such, will let the winter weather advisory ride, with the highest confidence of the light accumulations closer the Altamaha River Basin. Snow flurries could also drop down to near coastal northeast FL around the JAX metro area this evening, but no accumulation anticipated. The window of greater chances are from about 5 PM to 10 PM, but probably a bit longer for southeast GA until midnight.

For winds, gustier winds expected to develop with most recent gusts around 30-32 mph. Expect the peak winds to develop over the course of the next few hours, reaching upwards of 35-45 mph, and can't rule out 50 mph where the best boundary layer mixing develops. This higher max wind gust would mainly be toward the coastal areas north of St Augustine. Wind Advisory remains in effect through tonight.

SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/

Dry weather conditions will be in place through the period with low wind chill values expected on Sunday morning with values potentially in the single digits and then warming slightly in the afternoon as low pressure moves off to the northeast and high pressure conditions settle in over the region. Daily high temperatures will be in the lower to mid 40s on Sunday and warm to be in the lower to mid 50s. Overnight low temperatures will be in the lower to mid 20s for the end of the weekend and will rise slightly to be in the upper 30s and lower 30s on Monday. Freezing and frost conditions will develop during the overnight and early morning hours.

LONG TERM /TUESDAY THROUGH FRIDAY/

High pressure will move off to the east Tuesday and into Wednesday morning. The positioning of the high, will result in a more southwesterly flow on Tuesday allowing temperatures to reach up into the lower 60s, with overnight low temps in the 30s but with only a few patchy inland areas expected to drop below freezing. A cold front will move southeast across the forecast area on Wednesday and Thursday, resulting in an increased chance for showers before the end of the week. Temperatures will be near to slightly above normal for midweek and then trend be below average on Thursday. High pressure will build in from out of the southwest by Friday bringing in below average temps for the end of the period.

AVIATION /18Z SATURDAY THROUGH 18Z SUNDAY/

Strong cold front moved through this morning and will see increasing surface winds at the terminals from WNW to NW direction at 15-25 kts with gusts of 30-35 kts, potentially near 40 kts at SSI and SGJ through the evening hours. The best chance of showers and then potentially transitioning to snow will be at SSI late afternoon through 03z. Some chance for MVFR cigs around 23z- 04z at SSI. Otherwise, VFR prevails cigs later this afternoon, but clearer skies expected after 06z tonight.

By 12z Monday, breezy still but not as high as this afternoon will be.

MARINE

Low pressure will strengthen offshore of the Carolina Atlantic coast today. Strengthening offshore flow increases this afternoon with Gale conditions expected across all local waters through tonight. A chance of showers and even a few snow showers moves across portions of southeast Georgia then southward across local waters overnight. Occasional gusts near 50 knots possible tonight. As strong offshore flow develops today into tonight, a period of low water levels is likely tonight around low tide. Winds and seas begin to subside late Sunday afternoon into Monday to Small Craft Advisory conditions as high pressure builds across the Gulf Coast states. The high builds over the Florida peninsula Tuesday with seas falling below Advisory levels. The next cold front approaches from the west Wednesday.

Rip Currents: Low to moderate risk rest of today as strong offshore flow continues and combined seas increase. Offshore flow continues Sunday and so surf will be relatively minimized with wind wave direction going offshore. Higher risk possible Monday into Tuesday as some northeast swells affect the area.

FIRE WEATHER

- Inland MinRH values less than 30 percent Sunday and Monday - Widespread high dispersions Sunday and Monday - Areas of high dispersions Wednesday

A strengthening area of low pressure will move to the northeast of the area over the weekend. Elevated winds are expected over the weekend, with dangerously cold wind chills Sunday morning. High pressure will build over Monday and Tuesday. A cold front will move through on Wednesday and into Thursday bringing increased chances for showers. High pressure will build to the southwest on Friday.

FOG POTENTIAL AND OTHER REMARKS: Light snow is possible this evening over parts of southeast GA, with very light accumulations under a half inch possible. Snow flurries will be possible near the coasts as well Tonight.

TIDES/COASTAL FLOODING

The combined impact of already seasonably low astronomical tides and stronger WNW offshore winds tonight could create low mean lower low water levels at coastal locations.

CLIMATE

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

Record Low Maximum Temperatures:

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 44 19 41 21 / 10 10 0 0 SSI 50 24 43 28 / 0 20 0 0 JAX 52 20 44 24 / 0 0 0 0 SGJ 54 23 45 28 / 0 0 0 0 GNV 53 20 45 22 / 0 0 0 0 OCF 55 20 45 21 / 0 0 0 0

JAX WATCHES/WARNINGS/ADVISORIES

FL...Freeze Warning from 7 PM this evening to 11 AM EST Sunday 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. Extreme Cold Warning from 9 PM this evening to 10 AM EST Sunday 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. Wind Advisory until 7 AM EST Sunday for FLZ023-024-030-031-038- 124-125-132-136>138-140-225-232-233-236-237-240-325-333- 340-425-433-533-633. GA...Freeze Warning from 7 PM this evening to 11 AM EST Sunday for GAZ132>136-149-151>154-162-163-165-166-250-264-350-364. Extreme Cold Warning from 9 PM this evening to 10 AM EST Sunday for GAZ132>136-149-151>154-162-163-165-166-250-264- 350-364. Wind Advisory until 7 AM EST Sunday for GAZ153-154-165-166. Winter Weather Advisory until 1 AM EST Sunday for GAZ133>136- 151>154-165-166. MARINE...Gale Warning until 1 PM EST Sunday for AMZ450-452-454-470-472- 474. Small Craft Advisory from 1 PM Sunday to 10 AM EST Monday for AMZ450-452-454. Small Craft Advisory from 1 PM Sunday to 3 PM EST Monday for AMZ470-472-474.