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

- Moderate Rip Current Risk at Area Beaches through Wednesday.

- Strong Cold Frontal Passage Expected on Thursday Night. Small Craft Advisory Conditions Likely from Thursday Afternoon through at Least Saturday Morning.

- Frost Possible Across Inland Southeast GA and the Suwannee Valley Early on Sunday Morning.

NEAR TERM /THROUGH TONIGHT/

Main Highlights:

- Increasing Cloud Cover Should Prevent Fog Formation Tonight.

Afternoon surface analysis depicts high pressure (1022 millibars) situated along the southeastern seaboard. Aloft...zonal flow prevails across the Deep South, downstream of a cutoff trough spinning over northern and western Texas. Latest GOES-East derived Total Precipitable Water imagery indicates that a seasonably dry air mass remains in place across most of our area, with PWATs generally ranging from 0.5 to 1 inch, while values have recently climbed just above 1 inch across portions of north central FL. Deepening southwesterly flow downstream of the aforementioned upper trough over Texas was transporting high altitude cloud cover across our area this afternoon. A lingering dry air mass and filtered sunshine has boosted temperatures to the mid and upper 70s at 18Z, with a few locations in north central FL touching 80 degrees. Dewpoints ranged from the lower 40s across portions of southeast GA to the lower 60s for portions of north central and coastal northeast FL.

High altitude cloudiness will increase through late this afternoon as the cutoff trough over northern and western TX dislodges and begins progressing eastward across as a shortwave trough. Otherwise, filtered sunshine and a dry air mass will allow temperatures to climb to the 75-80 degree range this afternoon, except lower 80s across north central FL. These values are about 5 degrees above mid- November climatology.

Increasing mid and high altitude cloudiness overnight downstream of the approaching shortwave trough should prevent fog formation across our area, with light winds allowing lows to fall to the 50-55 degree range for most of southeast GA and inland portions of northeast FL, ranging to the low and mid 60s for portions of north central and coastal northeast FL. These values are near to slightly above mid- November climatology.

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/

Main Highlights This Period:

- Moderate Rip Current Risk at Area Beaches on Wednesday.

- Breezy Westerly Winds on Thursday.

A pattern shift will begin through the latter half of the week as a large upper trough carves out across the eastern CONUS. Light winds and dry low levels will persist through Wednesday as the "lead" shortwave drifts overhead during the afternoon hours. Enough lift and mid level moisture will support light stratiform showers and sprinkles with the fast moving shortwave for locations along and north of I-10. Behind that feature, a weak cold front while pass as a formidable surface low shifts toward the Mid Atlantic and begins to quickly deepen through Thursday. The response to the intensifying low to the north will be a tightening local gradient and breezy offshore (westerly) winds with gusts around 15-25 mph. A second dry cold front passage Thursday night will push in drier and cooler air as flow turns northwesterly to end the work week. Breezy conditions and a fairly dry boundary layer will keep fog potential very low each night.

Despite the weak cold front passage Wednesday night, temperatures will be temperate each day with highs in the mid to upper 70s. Lows tumble from the mid/upper 50s Wednesday night to the mid 40s and low 50s Thursday night behind the front.

LONG TERM /FRIDAY THROUGH TUESDAY/

Main Highlights This Period:

- Much cooler and drier Friday through Sunday.

- Inland Frost Potential Southeast GA/Suwannee Valley Sunday Morning.

Much cooler and breezy conditions will develop Friday and persist through the weekend. A stagnant upper trough will remain situated across the eastern US with embedded shortwaves rotating around it, sending reinforcing cold air into the area. As the cold Canadian surface ridge leaks into the region Saturday night, temperatures will chill to their lowest with lows into the mid 30s across portions of SE GA and the Suwannee Valley. Calming winds with the near-freezing temperatures will lend the potential for patchy to areas of frost development Saturday night. High pressure will then build to the north and then northeast Sunday through early next week resulting in gradual warming and breezy northeasterly winds. Rain chances will begin to increase next week as the southern stream begins to reengage allowing shortwaves to track across the Gulf and Florida.

AVIATION /18Z TUESDAY THROUGH 18Z WEDNESDAY/

VFR conditions will prevail at the regional terminals. Mid and high cloud cover will gradually increase and thicken overnight tonight, which should negate fog formation during the predawn and early morning hours. A brief period of MVFR visibilities will be possible after 07Z through around 11Z at VQQ, but confidence was too low to mention in the TAF at this time. Southwesterly surface winds sustained at 5-10 knots will prevail through around 23Z at the inland terminals, while a late developing Atlantic sea breeze shifts surface winds to east- southeasterly at SGJ towards 20Z and southerly at SSI towards 21Z. Surface winds will then diminish below 5 knots by 03Z. West or west-northwesterly surface winds will develop after sunrise, with sustained speeds increasing to around 5 knots towards 14Z Wednesday.

MARINE

High pressure positioned along the southeastern seaboard will weaken and shift offshore tonight as a disturbance aloft progresses eastward towards the southeastern states. This system may produce isolated showers as it moves across our local waters on Wednesday afternoon and evening. Meanwhile, a strong cold front will push southward from the Ohio and Tennessee Valleys on Thursday, with breezy west southwesterly winds developing after midnight on Wednesday night ahead of this front. Small Craft Advisory conditions are expected to develop by late Thursday afternoon and evening as westerly winds strengthen just ahead of the frontal passage, followed by an extended period of strong northwesterly winds beginning after midnight on Thursday night. Small Craft Advisory conditions are expected to continue through at least Saturday morning across our local waters. High pressure will then build over the Tennessee Valley on Saturday, with winds shifting to northerly on Saturday afternoon and evening, allowing seas to briefly subside. Breezy northeasterly winds are forecast to develop by Sunday as a stronger high pressure center builds southward from the Great Lakes region and weak low pressure potentially develops over the northern Gulf.

Rip Currents: A lingering long period east-northeasterly ocean swell will keep a moderate risk in place at all area beaches through Wednesday. Strengthening offshore winds from Thursday through Saturday should yield a low risk. Breezy northeasterly winds developing by Sunday will likely create a moderate risk.

FIRE WEATHER

- High Daytime Dispersions Possible Thursday And Friday.

Dry conditions and light westerly winds persist through Wednesday, with poor to fair (30-40 units) daytime dispersions. Near critical humidity, down to the upper 20s to 30s, will develop again this afternoon and be followed by a slight upward trend Wednesday. There is a chance for very light rain and sprinkles Wednesday afternoon with a passing disturbance but only a few hundredths of rain are expected. A strong cold front will arrive Thursday night bringing breezy westerly winds ahead of it and gusty northwesterly winds behind it. The cold air will plunge into the area Friday and through the weekend and may lead to areas of frost for the Suwannee Valley and inland Southeast GA Saturday night/Sunday morning. Next chance for meaningful rain isn't expected until next week.

FOG POTENTIAL AND OTHER WEATHER REMARKS: Limited fog development through Wednesday with near-zero chance Thursday through Sunday. Patchy Frost possible across inland portions of southeast GA and the Suwannee Valley early on Sunday morning.

PRELIMINARY POINT TEMPS/POPS

AMG 50 76 54 76 / 10 10 0 0 SSI 57 77 58 77 / 10 10 0 0 JAX 55 79 56 78 / 10 20 0 0 SGJ 61 78 60 77 / 10 20 0 0 GNV 59 80 57 78 / 10 20 0 0 OCF 61 81 59 78 / 10 10 0 0

JAX WATCHES/WARNINGS/ADVISORIES

FL...None. GA...None. MARINE...None.