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

- Winter Weather Advisories Sunday Morning for Coffee, Jeff Davis, Atkinson, Appling and Bacon Counties. Snow Accumulation Less than an inch possible on Grassy & Elevated Surfaces. Brief Period of Snow Flurries Possible for the Rest of Inland Southeast GA

- Small Craft Advisories for Sunday and Sunday Night

- Widespread Freezes from Sunday Night through Tuesday Night. Hard Freezes Possible for Inland Southeast GA, Light Freezes Elsewhere Inland. Frost Potential at Coastal Locations Sunday Night and Monday Night. Low Wind Chill Values of 20- 25 Early on Monday and Tuesday Mornings

NEAR TERM /THROUGH TONIGHT/

This afternoon...South to Southwest flow ahead of approaching cold frontal boundary will continue to increase cloud cover across all of SE GA and most of NE FL, but not before Max temps reach into the lower to middle 60s across SE GA and around 70F across most of NE FL. While a few sprinkles will be possible out of the thickening clouds across SE GA and the Suwannee Valley of inland North FL late in the day not expecting measurable rainfall.

Tonight...Cold frontal boundary will sag southward through inland SE GA this evening with more widespread rainfall developing along with falling temps through the 40s, while it will take until after midnight for rainfall to spread into coastal SE GA and into NE FL towards the early morning hours. Will be a cold rain as temps fall into the mid/upper 30s across inland SE GA and lower/middle 40s elsewhere by sunrise Sunday morning, with any of the wintry mix holding off until the mid morning hours on Sunday for inland SE GA. Rainfall amounts tonight will be around 0.25" for inland SE GA and the Suwannee Valley of inland North FL and 0.10" or less for coastal SE GA and the rest of NE FL.

SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/

Dynamic storm system will continue to impact the region through most of Sunday, bringing beneficial rain to much of the area but especially north of about the I-10 corridor. Confidence continues to grow with respect to some winter weather impacts over far interior GA, with Jeff Davis, Appling, Bacon, Coffee, and Atkinson Counties now all in a Winter Weather Advisory late tonight through Sunday Afternoon where snow is expected to mix in with periods of rain at times, especially during the late morning and early afternoon hours. Overall still not expecting much in the way of accumulation as any snow will be falling during the daylight hours and most of the ground will be too warm. However, some light accumulation of up to around 0.5" will be expected in some areas of these counties, which will mainly occur on grass or unpaved roads. As rainfall starts to wrap up from west to east throughout the afternoon, a few snowflakes could mix in with subsiding showers as far south and east as areas such as Waycross, Jesup, Homerville, however no accumulation would be expected. In terms of QPF amounts, generally around 0.25-0.33" south of I-10 with periods of rain showers, and up to 0.5-0.75" the further north and west into Georgia you go. Have trended lower with guidance for high temps Sunday thanks to the strong cold air advection and dynamic cooling expected, with highs generally in the 40s to near 50 north of I-10, and 50s south.

Strong cold air advection will continue to fill into the region tonight and into Monday behind the departing system, with clearing skies and at least a light freeze likely for the vast majority of the CWA, and hard freeze inland. Freeze Watch has already been issued for the whole area, and will also be flirting with Cold Weather Advisory wind chills Monday Morning as well across most of northeast FL. Additions/upgrades of these products are likely to occur with the next forecast package early Sunday Morning. In terms of numeric values, generally mid to upper 20s over the interior, and upper 20s to low 30s towards the coast and St. Johns River Basin.

High pressure will remain to the northwest of the region through Monday and Monday Night, with another cool day in store amidst a light north to northwesterly flow. Despite mainly sunny skies, high temps are only expected to reach into the low to mid 50s for most. Another inland freeze will be likely Monday Night with a light freeze and/or some frost likely close to the coast and St. Johns River Basin as well: lows will be generally around 25-30F inland low to mid 30s east of I-95.

LONG TERM /TUESDAY THROUGH SATURDAY/

High pressure slowly shifts from northwest of the region on Tuesday to northeast of the region into the Atlantic by Wednesday, which will result in an increasingly onshore flow. Guidance is then rather split on the impacts of the next frontal boundary and upper level energy moving across the area around Wednesday Night and Thursday, with the GFS indicating a much drier and quick frontal passage and the Euro bringing higher moisture and better dynamics with the frontal passage during the same time frame. For now have kept slight chance to chance PoPs for Thursday, which will be narrowed down over the next several days. High pressure then looks to build back in from the northwest and north for the end of next week behind the front. Temperatures will generally moderate mid week with the onshore flow, remaining near normal Wednesday through Friday after another day below normal Tuesday.

AVIATION /18Z SATURDAY THROUGH 18Z SUNDAY/

VFR conditions will prevail at the regional terminals through at least 09Z Sunday. Rainfall and shift in Winds to Northwest towards sunrise Sunday will bring lowering CIGS to MVFR around 12Z, with continued lowering to IFR CIGS/MVFR VSBYS by 15Z at all regional terminals, along with NW winds increasing to 10-15 knots and gusts to around 20 knots at times through the end of the TAF period.

MARINE

Arctic cold front will approach the region this afternoon and evening with prevailing southerly winds. Showers will overspread our local waters as this front passes through late tonight and Sunday morning. Northwesterly winds will strengthen after midnight, reaching Small Craft Advisory levels on Sunday morning. Arctic high pressure will remain centered to the west or northwest of our region early next week, keeping breezy northwest to northerly winds and elevated seas in place through midweek. High pressure will then weaken over the southeastern states on Wednesday, allowing for onshore winds to develop across our local waters. Weak low pressure traversing the northern Gulf coast on Wednesday night and Thursday may spread a round of scattered showers through Thursday night, mainly for the northeast Florida waters.

Rip Currents: SE GA Moderate Sunday NE FL Moderate Sunday

FIRE WEATHER

Southerly winds throughout the day today will shift towards the southwest to eventually northwest tonight and into Sunday as a cold front drops just south of the area. A few showers will be possible across inland GA through this evening, though periods of rain are expected to begin overnight tonight and continue through Sunday afternoon. Will be primarily a beneficial rain, though some snow will mix in at times over far interior GA, though accumulation, if any, is expected to be less than a half inch. Despite stronger winds compared to Friday, dispersions will still be only in the fair range for most today, and borderline poor in some areas such as coastal GA and the Suwannee Valley. Dispersions will be fair to good Sunday, especially later in the day once precip comes to an end.

Another cool and dry airmass will build in Sunday Evening through Monday, dropping minRH values around 30-35% Monday and closer to 25- 30% by Tuesday. Fair to good dispersions will be expected through Monday despite weakening low level northwesterly winds.

FOG POTENTIAL AND OTHER REMARKS: As mentioned above, light snow accumulations are possible over far inland southeast GA on Sunday. Hard inland freezes are likely for inland southeast Georgia early on Monday, Tuesday, and Wednesday mornings, with a hard freeze possible early on Monday morning for inland locations along the Interstate 10 corridor. Light freezes and frost potentially may extend to coastal locations early next week.

PRELIMINARY POINT TEMPS/POPS

AMG 37 44 24 51 / 100 100 0 0 SSI 42 51 31 53 / 70 100 0 0 JAX 43 53 26 56 / 60 100 0 0 SGJ 48 58 32 56 / 30 90 0 0 GNV 46 54 27 57 / 50 90 0 0 OCF 47 56 27 57 / 50 80 0 0

JAX WATCHES/WARNINGS/ADVISORIES

FL...Freeze Watch from late Sunday night through Monday 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. GA...Freeze Watch from late Sunday night through Monday morning for GAZ132>136-149-151>154-162-163-165-166-250-264-350-364. Winter Weather Advisory from 7 AM to 1 PM EST Sunday for GAZ132>135-149. MARINE...Small Craft Advisory from 7 AM to 7 PM EST Sunday for AMZ450- 452-454. Small Craft Advisory from 7 AM Sunday to 1 AM EST Monday for AMZ470-472-474.