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

- Freeze Warnings and Frost Advisories for most locations through early Wednesday morning.

- Humidity values fall to near critical thresholds this afternoon for portions of north central and inland northeast FL.

- Moderate rip current risk at all area beaches through Thursday.

- Severe to Extreme Drought Conditions Continue Region-Wide

- Beneficial Rainfall and Isolated Thunderstorms Possible from Thursday through Saturday.

NEAR TERM /THROUGH TONIGHT/

Weather Hazards for this period: - Freeze Warnings and Frost Advisories for most locations through early Wednesday morning.

- Humidity values fall to near critical thresholds this afternoon for portions of north central and inland northeast FL.

Overnight surface analysis depicts gradually weakening high pressure (1025 millibars) centered over central FL. Meanwhile, a series of frontal boundaries were migrating across the Great Lakes states, the Upper Midwest, and the Plains states. Aloft...deep northwesterly flow prevails from the Rockies to the southeastern states in between a potent shortwave trough that was pivoting across the Great Lakes states and stout ridging that was positioned near Baja California. A 150 knot jet streak at 250 millibars (around 35,000 feet) was generating a shield of mostly high altitude cloud cover across the southeastern U.S. that was overspreading our area. Low level south and southwesterly flow was generating enough warm air advection to keep temperatures mostly in the 35-40 degree range as of 06Z, except at coastal locations, where temperatures remain generally in the 40- 45 degree range. Dewpoints ranged from the upper 20s to the mid 30s.

Surface ridging located over central FL should allow for surface winds to decouple at inland locations overnight. A very dry low level air mass will otherwise persist through Wednesday, and only thin cirrus overhead should allow for temperatures to fall to the 30- 35 degree range at most inland locations towards sunrise. We will keep the existing freeze warnings and frost advisories in place for now, with coastal lows likely remaining in the upper 30s to around 40.

High pressure will then gradually push east-southeastward today, moving offshore of the southeast FL coast this afternoon. Warm air advection will continue, with a tightening local pressure gradient resulting in breezy southwesterly winds this afternoon. The lingering dry air mass should allow dewpoints to crash into the 30s this afternoon for portions of inland north central and northeast FL, where a few spots near the Ocala National Forest could briefly approach Red Flag criteria this afternoon as temperatures rise into the lower 70s for all inland locations. A pinned Atlantic sea breeze boundary may keep coastal highs in the 65-70 degree range, but these values are near or just slightly above late February climatology for our area.

Mid-level flow will become more zonal tonight, with low level return flow around the periphery of the Atlantic surface ridge advecting moisture from the northeastern Gulf and Apalachee Bay across inland portions of southeast GA overnight. An isolated shower or sprinkle may fall towards sunrise for locations near the Alapaha, Ocmulgee, and upper Altamaha Rivers beneath a thickening cumulus or stratocumulus field. Warm air advection and thickening cloud cover should keep lows in the lower 50s for much of southeast GA. Interludes of mostly high altitude cloud cover will prevail elsewhere, with decoupling winds and a drier air mass yielding lows in the 40s for inland north central and northeast FL, ranging to around 50 at coastal locations.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/

Main Highlights During the Period: - Beneficial rain and isolated thunderstorms Friday

Deep southwest flow will enhance moisture across the area, as a cold front approaches from the northwest. Ahead of the front it will be breezy, especially during the afternoons, with temperatures rising into the 70s to low 80s by Friday. Showers will enter interior southeast Georgia Thursday morning, mainly staying north of the FL/GA state line through the night. Thunder chances are low, but non- zero overnight. By Friday at daybreak, showers will spread into northeast Florida with thunder chances increasing in the afternoon mainly north of I-10 since activity really reaches northeast Florida closer to sunset.

Rainfall totals are forecast to be about 0.75-1.25" Thursday through Saturday night.

LONG TERM /SATURDAY THROUGH TUESDAY/

Main Highlights During the Long Term Period: - Beneficial Showers and Possibly a Few Storms Saturday

The front will briefly stall across northeast Florida Friday night through Saturday afternoon before exiting the area southward Saturday evening. Showers will linger across the area throughout the day, with the highest coverage and chances for isolated thunderstorms being over north central Florida. By sunset, land areas will be dry with showers over the local Atlantic waters as northeasterly winds develop behind the front. With the onshore breeze, rain will be present over the Atlantic waters Sunday, with a few showers drifting onshore near the northeast Florida coast. Winds will increase early next week, bringing showers further inland as a strong high pressure builds over the northeastern US. Temperatures during this period will be in the 70s for most of the area, with onshore winds keeping the southeast Georgia coast in the upper 60s.

AVIATION /06Z WEDNESDAY THROUGH 06Z THURSDAY/

VFR conditions will prevail at the regional terminals. Periods of high altitude cirrus will stream overnight, with a flat, scattered cumulus field based around 3,500 - 4,500 feet developing after 15Z. South-southwesterly surface winds sustained around 5 knots overnight will increase to 5-10 knots by 15Z and then 10-15 knots and gusty after 16Z. Surface winds will shift to southerly at SSI and SGJ after 19Z as a pinned Atlantic sea breeze boundary remains just inland of these coastal terminals. Surface winds elsewhere will shift to southerly towards 00Z Thursday, with speeds gradually diminishing to 5-10 knots by 02Z.

MARINE

High pressure centered over the Florida peninsula will shift offshore of the southeast FL coast by early Wednesday evening. Breezy southwesterly winds will prevail through Thursday across our local waters, especially offshore, where Caution level speeds are forecast. A slow moving frontal boundary will then enter the southeastern states on Thursday night, with a few showers possible after midnight. Showers and a few embedded thunderstorms will then increase in coverage from Friday through Saturday night. High pressure building over the Carolinas in the wake of this frontal boundary will create an onshore wind flow this weekend. Easterly winds may strengthen early next week as a stronger high pressure center builds over New England and wedges down the southeastern seaboard, with a developing coastal trough over our local waters developing rounds of scattered showers.

Rip Currents: A long period east-northeasterly ocean swell will deliver a higher end moderate rip current risk at all area beaches today. This swell will begin to fade on Thursday, resulting in a lower end moderate risk at area beaches. A low rip current risk appears to be likely on Friday and Saturday due to light winds and lower swell periods, with a moderate risk returning by Sunday due to gradually strengthening onshore winds that will continue into early next week.

FIRE WEATHER

- Areas Of High Dispersions Wednesday And Thursday - PATCHY HIGH NIGHTTIME DISPERSION WEDNESDAY NIGHT OVER INLAND SE GA

Breezy southwest winds today will increase moisture across much of northeast Florida and southeast Georgia, however minRH values remain below 35% generally east of the line from Gainesville to Jacksonville. Winds will be gusty Wednesday and Thursday afternoons, creating areas of high daytime dispersion. An approaching cold front will bring showers and storms Thursday through Saturday, with winds shifting to northeasterly Saturday behind the front. Rainfall totals are forecast to be about 0.75-1.25" Thursday through Saturday night.

FOG POTENTIAL AND OTHER REMARKS: Significant fog developments are not expected. Thunderstorms are the forecast for Thursday night through Saturday evening.

PRELIMINARY POINT TEMPS/POPS

AMG 72 52 74 57 / 0 10 50 50 SSI 65 53 71 58 / 0 0 10 30 JAX 72 48 78 56 / 0 0 10 10 SGJ 69 49 77 56 / 0 0 0 10 GNV 71 46 78 56 / 0 0 0 10 OCF 71 44 78 55 / 0 0 0 10

JAX WATCHES/WARNINGS/ADVISORIES

FL...Frost Advisory until 8 AM EST this morning for FLZ021-038-120- 132-138-220-333-433-533-633. Freeze Warning until 8 AM EST this morning for FLZ023-024-030- 031-035-136-137-140-232-236-237-240-322-340-422-425-522. GA...Frost Advisory until 8 AM EST this morning for GAZ132>136-149- 154-162-166. Freeze Warning until 8 AM EST this morning for GAZ151>153-163- 165-250-264-350-364. MARINE...None.