Marine Weather and Tide Forecast for Macclenny, FL

SYNOPSIS
Issued at 354 AM EDT Sat May 17 2025

Overnight surface analysis depicts Atlantic high pressure extending its axis westward across the FL peninsula and the southeastern Gulf. Meanwhile, pair of cold fronts extend southwestward from strong low pressure (990 millibars) that was migrating across the Great Lakes region, with these boundaries pushing across the Upper Midwest and approaching the Ohio, Tennessee, and lower Mississippi Valleys
Aloft
deep-layered ridging that extends across the Gulf and the FL peninsula was flattening as deep troughing migrates across the Great Lakes states, with a 120 knot jet streak positioned around 250 millibars (around 35,000 feet) migrating across the Ozarks and the Tennessee Valley in between these features that was fueling a severe weather outbreak across the lower Mississippi and Tennessee Valleys. Latest derived Total Precipitable Water imagery indicates that a dry and subsident air mass prevails locally, with PWATs of only around 1 inch at most locations. Brisk northwesterly flow above 500 millibars (around 25,000 feet) located on the periphery of the ridge over the Gulf was advecting thin cirrus into our region, with thicker cirrostratus located upstream across the Deep South. A west-southwesterly breeze was keeping temperatures in the upper 60s and lower 70s at most locations as of 07Z, with dewpoints mostly in the low and middle 60s.

NEAR TERM
(Today and Tonight)
Issued at 354 AM EDT Sat May 17 2025

Cirrus cloud cover will overspread our region briefly this morning, with some thicker cirrostratus at times for locations along and north of Interstate 10. Thinner cirrus south of I-10 may allow for some low stratus ceilings and possibly some patchy fog to develop during the predawn and early morning hours today for inland portions of north central FL. Otherwise, ridging aloft will continue to flatten across the Gulf and FL peninsula as deep troughing migrates slowly eastward across the eastern Great Lakes through tonight. This will allow a frontal boundary to push through the Tennessee Valley and the Carolinas by late tonight. A ribbon of deeper moisture will pool downstream of this frontal boundary across central AL and GA this afternoon, with a jet streak migrating eastward across the Tennessee Valley and the Carolinas helping to develop a squall line of strong to severe thunderstorms that will approach the Altamaha and Ocmulgee Rivers by late afternoon. However, the best forcing and dynamics associated with this jet streak will remain situated just north of our area, likely resulting in the squall line breaking up while weakening towards sunset. Widely scattered showers and possibly and few thunderstorms will migrate across the Ocmulgee and Altamaha Rivers towards sunset, with activity then dissipating before reaching Waycross and points eastward to coastal southeast GA.

Our local pressure gradient will remain rather tight across our area today as the storm system passes well to the north of our region. High altitude cloudiness should thin out this afternoon. A hot, dry, and subsident air mass will persist for locations south of Waycross, and the Atlantic sea breeze may remain just east of area beaches until late afternoon, which will allow for another day of record breaking heat to again extend all the way to coastal locations. Increasing afternoon cloudiness will keep highs in the low to mid 90s for locations north of Waycross, while mid to upper 90s continue elsewhere. Dewpoints falling through the low and mid 60s this afternoon will keep maximum heat index values around 100.

Any leftover, low-topped convection over inland southeast GA should dissipate during the early to mid-evening hours. Debris clouds from this activity will thin out after midnight, setting the stage for fog and low stratus ceilings to advect eastward off Apalachee Bay and across the Suwannee Valley overnight. This bank of low stratus and fog should continue advecting eastward along the I-10 corridor during the predawn hours, possibly approaching the I-95 corridor towards sunrise. Lows tonight will again only fall to the upper 60s and lower 70s.

SHORT TERM
(Sunday through Monday night)
Issued at 354 AM EDT Sat May 17 2025

A broad high pressure ridge will extend across south FL this period. A front will be stalled across central GA on Sunday, then lift back to the north on Monday.

The flow aloft on Sunday will allow weak waves to move east across SE GA. These waves, coupled with convergence associated with frontal boundary, and diurnal heating will lead to potential for a few showers and storms over SE GA Sunday afternoon. Low level moisture will result in patchy fog potential across area Sunday night.

Dry weather is expected for Monday.

With the west southwest flow, the east coast sea breeze will struggle to move inland Sunday, likely not making it past I95. Highs inland in the middle 90s will be common. With the sea breeze having a harder time pushing inland, highs at the coast should still reach the lower 90s before the sea breeze moves inland. Temperatures will remain above average Sunday night. The sea breeze will once again struggle to push inland against the prevailing flow from the west southwest Monday. So, again the heat will get all the way to the coast before the sea breeze pushes in. Highs Monday will range from the middle 90s inland, to the lower to mid 90s coast. The above average temperatures will continue Monday night.

Inland fog potential Monday night due to flow off the Gulf.

LONG TERM
(Tuesday through Friday)
Issued at 354 AM EDT Sat May 17 2025

The high will push further away to the south southeast Tuesday, as a frontal system approaches from the northwest. Tuesday will be a dry day, with temperatures above seasonal averages. After a dry night Tuesday night, the front will move into the southeast Wednesday. The front will then move through the area through Thursday morning. A round of showers and thunderstorms will accompany the front Wednesday through early Thursday. A significant change in temperatures is expected with the front, hinting at the potential for strong to possibly severe storms with the passage.

Temperatures will continue above seasonal averages through Wednesday, then near to below Thursday into Friday.

AVIATION
(12Z TAFS) Issued at 734 AM EDT Sat May 17 2025

Low stratus, at IFR to LIFR levels, will persist as late as 13z at KVQQ & KJAX before lifting. This morning's stratus will be followed by VFR conditions with BKN cirrus at or above 20kft.
Westerly winds will increase after the inversion breaks this morning, with peak gusts around 20 kts through the early afternoon.
Though most airfields will be dry today, a decaying impulse across central Georgia may bring an isolated shower this afternoon and early evening, between 20z-24z. Westerly winds persist overnight but will trend light by daybreak Sunday as another round of low stratus pushes across NE FL.

MARINE
Issued at 354 AM EDT Sat May 17 2025

Atlantic high pressure will continue to extend its axis westward across the Florida peninsula and into the eastern Gulf through early next week, creating a prevailing west southwesterly wind flow across our local waters. Seas of 2 to 3 feet will prevail both near shore and offshore through Tuesday night. Meanwhile, a frontal boundary currently pushing across the Ohio and Tennessee Valleys will stall to the north of our area on Sunday, with showers and possibly a few strong thunderstorms possibly impacting the Georgia waters during the late afternoon and evening hours.
This front will lift northward early next week in advance of a cold front that will move across our local waters on Wednesday night and early Thursday. Scattered showers and thunderstorms may accompany this frontal passage on Wednesday afternoon and night.
Strengthening southwesterly winds will result in seas building slightly to 3-4 feet offshore by midweek. High pressure will then build into the southeastern states late this week and during the beginning of Memorial Day weekend in the wake of this frontal passage.

Rip Currents: Prevailing offshore winds and low surf heights will keep a low risk in place at all area beaches today. Afternoon sea breezes may combine with a lingering easterly ocean swell to create a moderate risk at the northeast FL beaches on Sunday and Monday, but we opted to keep the risk low at this time due to expected low surf heights that will persist through at least midweek.

FIRE WEATHER
Issued at 354 AM EDT Sat May 17 2025

A dry and very hot air mass will continue across our region today, with only isolated late afternoon and evening thunderstorms possible for locations north of Waycross. Minimum humidity values will fall to around 30 percent this afternoon for locations south of Waycross, extending all the way to coastal locations, as the Atlantic sea breeze remains pinned along area beaches. Otherwise, breezy transport winds will combine with elevated mixing heights to create pockets of high daytime dispersion values at inland locations, while good values otherwise prevail. Widely scattered strong to isolated severe thunderstorms will be possible across southeast GA late on Sunday afternoon and evening. Minimum humidity values will fall to the 30-35 percent range for inland locations to the south of Waycross. Breezy westerly transport winds and elevated mixing heights will again create pockets of high daytime dispersion values at inland locations, with good values expected elsewhere. Surface and transport winds will shift to southwesterly on Monday, with elevated mixing heights again resulting in high daytime dispersion values at some inland locations, while good values otherwise prevail across our area.

CLIMATE
Issued at 354 AM EDT Sat May 17 2025

Daily Record High Temperatures through Wednesday at our designated climate sites:

Sat 5/17 Sun 5/18 Mon 5/19 Tues 5/20 Wed 5/21 -------------------------------------------------- Jacksonville 96/1995 96/1899 97/1960 99/1962 99/1938 Gainesville 96/1915 97/1930 99/1899 97/1938 100/1938 Alma, GA 94/2001 95/2001 97/1960 99/1962 97/1962 Craig Airport 93/2001 93/2001 92/2006 97/2006 98/2006

PRELIMINARY POINT TEMPS/POPS
AMG 92 71 92 68 / 20 10 50 0 SSI 93 74 90 72 / 10 0 30 20 JAX 98 69 97 68 / 0 0 0 0 SGJ 96 70 94 69 / 0 0 0 0 GNV 95 67 95 65 / 0 0 0 0 OCF 93 67 93 67 / 0 0 0 0

JAX WATCHES/WARNINGS/ADVISORIES
FL...None.
GA...None.
AM...None.