Marine Weather and Tide Forecast for St. Simons, GA

SHORT TERM
(Sunday through Monday night)
Issued at 157 PM EDT Sat Jun 14 2025

Deep-layered ridging positioned over the FL peninsula will begin to nudge northward on Sunday as a de-amplifying trough progresses eastward across the southern Appalachians. This weather pattern will keep southwesterly flow in place across our area, with PWATs remaining around 2 inches fostering the development of scattered to numerous thunderstorms during the afternoon, with activity initially developing along the inland moving Gulf coast sea breeze in the Suwannee Valley and inland north central FL around or just before noon, with convection then developing along a pinned Atlantic sea breeze located just east of I-95 during the early to mid-afternoon hours. Mesoscale boundary collisions during the late afternoon hours may result in a few storms pulsing and becoming strong, mainly for locations east of U.S.-301 in northeast and north central FL, with isolated stronger storms potentially producing downburst winds of 40-50 mph, frequent lightning strikes, and torrential downpours. Early afternoon highs will generally reach the lower 90s inland and the upper 80s to around 90 at coastal locations, with maximum heat index values generally topping out in the 97-103 range. Deeper southwesterly flow should push convection offshore before midnight, with debris clouds thinning out overnight. Lows will only fall to the low and mid 70s inland, ranging to the mid and upper 70s at coastal locations.

Ridging aloft will nudge its axis over north central FL on Monday, allowing low level flow to back to a more southerly direction with decreasing speeds for areas south of I-10, while southwesterly flow prevails for locations north of I-10. A drier air mass associated with a Saharan Air Layer (SAL) over south FL will attempt to expand northward into central FL, but PWATS should still remain near mid-June climatology across most of our area. A looser pressure gradient will allow for both the Atlantic and Gulf coast sea breezes to push further inland, with colliding mesoscale boundaries along the U.S.-301 corridor again possibly resulting in pulsing storms.
Gradually strengthening subsidence may limit coverage to scattered for much of inland southeast GA, but numerous showers and storms are expected elsewhere inland during the afternoon hours, with activity possibly lingering well into the evening for inland northeast and north central FL. Temperatures will likely increase a few degrees at inland locations as subsidence strengthens, with low to mid 90s and maximum heat index values reaching the 100-105 range. Coastal highs should approach 90 before the sea breeze moves inland. Lows on Monday night will again generally fall to the low and mid 70s.

LONG TERM
(Tuesday through next Saturday)
Issued at 157 PM EDT Sat Jun 14 2025

The axis of deep-layered ridging will continue to lift northward across our region on Tuesday and Wednesday. Low level southerly flow should advect a drier air mass that will be in place across the FL peninsula northward into our region, with strengthening subsidence and PWATS falling slightly below climatology resulting in only widely scattered afternoon and evening thunderstorms, mainly for locations west of the U.S. Highway 301 corridor. Slightly higher coverage may be possible for locations west of I-75 in the Suwannee Valley towards sunset on both Tuesday and Wednesday, where the Atlantic sea breeze will collide with a slower moving Gulf coast sea breeze. Less convective coverage should allow highs to soar to the mid 90s inland and the lower 90s at area beaches, with maximum heat index values climbing to around 105 during the afternoon hours. Lows will remain in the mid 70s inland and the upper 70s to around 80 at coastal locations, where a light southerly breeze will continue overnight.

Convective coverage will likely increase late this week and into the weekend as troughing progresses across the eastern U.S. Ridging aloft will begin to sink southward in advance of this approaching trough on Thursday, but the drier air mass associated with the aforementioned SAL over the FL peninsula lingering on Thursday, which could limit afternoon and evening convective coverage. Widely scattered storms developing along a more dominant Gulf coast sea breeze should encounter a pinned Atlantic sea breeze boundary along the I-95 corridor late in the day, possibly resulting in a few strong storms for coastal locations towards sunset. Scattered activity could linger into the evening hours on Thursday across southeast GA as temperatures aloft cool with the approach of the upstream trough. Seasonably hot and humid weather will continue downstream of this trough for our area, with highs again reaching the low to mid 90s, with heat index values soaring to around 105. Southwesterly flow will continue these hot and humid conditions through Friday and Saturday. Gradually cooling temperatures aloft may result in an increasing threat for strong to isolated severe storms on Friday and Saturday afternoons, especially along the I-95 corridor, where mesoscale boundaries will likely collide during the afternoon hours.

FIRE WEATHER
Issued at 157 PM EDT Sat Jun 14 2025

Southwesterly transport winds will weaken slightly on Sunday, yielding fair daytime dispersion values across the Suwannee Valley and inland southeast GA, with poor values possible for locations south of the I-10 corridor. Southwesterly transport winds will continue on Monday, with breezy conditions during the afternoon hours creating good daytime dispersion values for inland locations along and north of the I-10 corridor, with fair values forecast elsewhere. Numerous afternoon and early evening showers and thunderstorms are forecast on Sunday and Monday, with only widely scattered showers and thunderstorms expected by Tuesday and Wednesday afternoons.

AVIATION
(18Z TAFS)
Issued at 104 PM EDT Sat Jun 14 2025

Convection will produce the potential for restrictions this afternoon into the evening. This activity will diminish during the evening hours, with a mainly dry overnight expected. Showers and thunderstorms will develop again toward the end of this TAF period.

MARINE
Issued at 157 PM EDT Sat Jun 14 2025

High pressure will generally be centered to the east through the upcoming week, with this ridge extending across coastal waters.

Rip Currents: Moderate through Sunday

PRELIMINARY POINT TEMPS/POPS
AMG 73 91 73 92 / 40 50 30 50 SSI 76 89 76 90 / 40 60 30 50 JAX 74 92 74 94 / 50 80 40 60 SGJ 75 91 74 92 / 40 60 30 60 GNV 73 93 73 94 / 30 60 20 60 OCF 74 92 73 93 / 30 60 20 60

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