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

- Critically Low Humidity Inland Through Early This Evening

- Areas of Frost Possible Inland Tonight and Early Saturday Morning

- Rain/Snow Mix Likely on Sunday for Far Inland Southeast GA

- Little to No Snow Accumulation Expected

- 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

NEAR TERM /THROUGH TONIGHT/

Cool and dry with plenty of sunshine expected today as high pressure remains in control, centered almost directly over the region. The high will slowly start to drift east of the Florida Peninsula this evening and through tonight as a cold front starts to approach from the northwest - though any impacts with this feature will hold off until after the near term period. Highs today will top out in the 50s area wide with only a very light and variable breeze starting to become more southeast to southerly later this afternoon and evening as the high shifts eastward.

Tonight, the southerly wind will start to pick up across much of the area after midnight, especially for western areas as the above mentioned cold front continues to approach and the pressure gradient tightens a bit. Temperatures will likely plummet rather quickly between about sunset and midnight before the wind starts to stir up the radiational cooling a bit and some clouds start to fill in as well, and therefore temps are likely to remain rather steady or possibly warm up a few degrees towards the morning hours. These factors are also expected to limit frost potential, and therefore have held off on a frost advisory at this time. Lows will range from the low to mid 30s over hte interior to the upper 30s to low 40s by the coast and St. Johns River Basin.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/

Saturday, mid to upper level troughing over the upper Midwest, western Great lakes and the mid MS river valley will begin to deepen as a shortwave just east of the Rockies dives south from the central to the southern plains into the base of the trough. This will create SW flow overhead as surface high pressure departs to the ENE with surface southerly winds turning southwesterly inland under mid and high level clouds increasing over the area ahead of cold front that will begin to slow as it approaches our area from the northwest with a few light showers by sunset near US 441 in SE GA. Highs rebound to 5 degrees above normal into the mid to upper 60s along and north of I-10 and around 70 south of I-10 with low 70s over north central FL.

Saturday night, the front will slowly sink through the area with showers spreading north and east from the Gulf coast across inland SE GA and the Suwannee Valley, becoming numerous to widespread in the pre-dawn morning hours as a sharp upper trough pivots eastward through the lower MS valley. This front will shift winds to northwesterly after midnight 5-10 mph, but temperatures will only lower into the upper 30s to lower 40s NW of Waycross. Above freezing surface and boundary layer temperatures will keep precipitation rain for through sunrise.

Sunday, the sharp upper trough and its strong shortwave energy will roll through the FL Gulf coast and along with a potent jet stream cranking up to 170 kts over the Mid Atlantic will create strong lift as our area falls within the favorable right front entrance region, which will support heavier showers shifting from the FL big bend NE across the Suwannee Valley and across SE GA during the morning to midday hours before overspreading eastward along I-10 and to the NE FL coast. An arctic cold front arriving midday over NW portions of SE GA will bring colder air aloft and dewpoints falling into the 20s into the early afternoon which will provide wet bulbing effect to induce a rain/snow mix or short window of light snow from Douglas to Baxley northwest. However, the timing with surface temperatures above freezing, mid daylight hours, and brief window of rain/snow mix will prevent accumulation to roads and bridges which will be too warm, but a very light coating on grassy surfaces could occur in the areas mentioned above if precip rates are fast enough to overcome the warmer surface temperatures. Again, not expecting impacts to roads due to the temperatures staying above freezing Sunday through the afternoon. As showers end over SE GA coast, a few flurries or snowflakes could fall, but no impacts expected and the event will be all rain over NE FL.

Showers will end mid afternoon over inland SE GA and exit into the Atlantic waters by sunset. Total rainfall from the system will be around half inch over SE GA and lighter over NE FL with a quarter to a tenth of an inch. Highs, likely occurring in the early part of the day will be in the mid 40s over inland SE GA and the upper 40s to low 50s along I-10 and the SE GA coast with mid to upper 50s towards the Southern St Johns river basin and Flagler coast.

Sunday night, skies will quickly clear as strong high pressure builds east from the TX Gulf coast to the mouth of the MS river with brisk NW winds and cold air advection that will cause our temperatures to plummet well into the low/mid 20s inland. A Freeze Watch has been posted for Sunday night and early Monday morning for hard freeze conditions returning to inland SE GA and inland NE FL with a light freeze into the coast and downtown Jacksonville. Enough northwest winds 4-8 mph will also create potential cold weather advisory conditions during the early morning hours Monday.

LONG TERM /MONDAY THROUGH FRIDAY/

The period will be marked by deep broad troughing over the eastern U.S. through midweek before weak ridging briefly moves over the east coast Thursday ahead of another developing trough over the MS river valley swings into the region on Friday. Strong high pressure over the central Gulf coast Monday will weaken slightly Monday night before strong high pressure builds in across the Ozarks and TN Valley on Tuesday, sending a dry cold front through the area Tuesday morning that will help to reinforce a cold and dry airmass over our area into Wednesday morning as the strong high builds just north of the area. This will support a potential freeze Tuesday AM over SE GA and and inland NE FL and again Wednesday morning, where a potential hard freeze could impact inland SE GA and the Suwannee Valley while north northeast winds protect the NE FL coast from a light freeze.

High pressure will shift away into the Atlantic waters Thursday with increasing clouds ahead of another potential storm system along the Gulf coast that may bring another round of rainfall to the area Friday, but still too early for rainfall amounts as a at this time and only have isolated to scattered showers for now at this juncture.

Temperatures will begin the period below normal through Wednesday morning and then trend to around normal Wednesday afternoon into Friday.

AVIATION /18Z FRIDAY THROUGH 18Z SATURDAY/

VFR conditions will prevail at the regional terminals today, with light winds mainly out of the south or southeast. Cloud cover will start to increase late tonight and through Saturday, though no operational concerns are expected at this time for the forecast period.

MARINE

High pressure centered almost directly over area waters will shift eastward through tonight, gradually inducing more of a south to southeast wind. Another Arctic cold front will enter the southeastern states on Saturday afternoon, crossing our local waters on Sunday morning. This front will be accompanied by showers through the early afternoon hours on Sunday. Northwesterly winds will strengthen by early Sunday morning, with Small Craft Advisory conditions likely through Sunday evening throughout our local waters. 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. High pressure will then start to position north of our waters towards midweek.

Rip Currents: SE GA Low Saturday NE FL Moderate Saturday

FIRE WEATHER

- Long Durations Of Critically Low Humidity Inland Today LOW DAYTIME DISPERSION VALUES TODAY FOR NORTH CENTRAL FL AND - The Coasts

A very dry air mass will prevail across our region through the rest of today, with long durations of critically low humidity values expected through the evening for all but the immediate Atlantic coastal communities. Light southerly winds will be expected today as high pressure moves east of the region, combined with the light transport winds will result in low/poor dispersions across most of northeast FL. Transport winds will be slightly higher over interior GA, where fair dispersions are forecast. Southerly surface and transport winds will increase tonight, especially for locations along and north of Interstate 10, creating generally fair daytime dispersion values on Saturday despite increasing cloud cover. A cold front will approach and move through the region Saturday Night and Sunday, bringing periods of rain as well as a possible mix with snow over far interior GA. A much drier and cooler airmass will move back into the area Sunday Night and into the start of next week.

FOG POTENTIAL AND OTHER REMARKS: A light inland freeze and areas of frost will be possible over parts of the interior late tonight and early on Saturday morning. Rain may briefly mix with sleet or light snow for locations northwest of Waycross on Sunday, with no snowfall accumulation currently forecast. Additional hard inland freezes are possible early on Monday, Tuesday, and Wednesday mornings, with light freezes and frost potentially extending to coastal locations early next week.

PRELIMINARY POINT TEMPS/POPS

AMG 33 65 36 45 / 0 10 70 80 SSI 43 65 40 51 / 0 0 50 90 JAX 34 70 41 53 / 0 0 40 90 SGJ 40 69 44 57 / 0 0 30 80 GNV 34 72 44 55 / 0 0 40 70 OCF 33 72 46 56 / 0 0 30 60

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. MARINE...None.