Marine Weather and Tide Forecast for St. Marys, GA

UPDATE

Evening surface analysis depicts weak high pressure (1018 millibars) situated over our region
Aloft
dry and zonal west-northwesterly flow prevails across the Deep South, in between troughing departing coastal New England and ridging building over the Bay of Campeche (southwestern Gulf). Latest GOES-East derived Total Precipitable Water imagery indicates a slowly moistening air mass across our region, with PWATs rising to near 1 inch for locations south of I-10 and east of I-75 in northeast and north central FL, while values elsewhere were slowly rising towards three-quarters of an inch. A few leftover marine cumulus and stratocumulus clouds from today's modest northeasterly wind surge remain across portions of coastal northeast FL, while patches of thin cirrus were otherwise drifting across our area in the west-northwesterly flow pattern.
Temperatures at 01Z were slowly falling through the 70s and mid to upper 60s across our area. Dewpoints ranged from the lower 50s for locations north and west of Waycross in interior southeast GA to the upper 60s along the northeast FL coast.

High pressure will push offshore overnight, allowing for a weak coastal trough to lift northward across our local Atlantic waters during the predawn and early morning hours on Saturday.
This feature should generate widely scattered showers after midnight across the Atlantic waters adjacent to northeast FL, but this shower activity will likely remain offshore from area beaches. Otherwise, low level flow will veer overnight, with a gradually moistening air mass allowing for at least patchy fog development towards sunrise, mainly for inland locations along and north of the Interstate 10 corridor. A few areas of locally dense fog will be possible. Lows will range from the upper 50s to near 60 for inland locations north of I-10, while low to mid 60s prevail elsewhere inland. A light onshore breeze and some increase in low cloud cover late tonight will keep lows in the upper 60s to lower 70s at coastal locations.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/

- Isolated thunderstorms along the I-75 corridor on Saturday Afternoon.

- Widely Scattered thunderstorms inland on Sunday Afternoon.

This weekend, the region remains on the western periphery of a Bermuda high maintaining southeasterly flow. Moisture will gradually increase back into the region from south to north allowing for isolated convection to develop along the sea breezes Saturday and becoming more scattered on Sunday. Given the southeast flow, the Atlantic sea breeze will be dominant resulting in the sea breeze merger occurring along and west of the I-75 corridor during the late afternoon and early evening hours.

Due to the onshore flow, cooler high temperature readings are expected at the coast each day in the mid 80s, whereas inland counties are likely reach the low 90s. Overnight the opposite will be true, more mild temps will be favored at the coast, while inland areas gradually fall to the mid/upper 60s.

LONG TERM /MONDAY THROUGH FRIDAY/

Main Highlights This Period:

- Scattered afternoon storms along sea breezes next week.

Ridging from high pressure in the Atlantic will gradually weaken over the region through mid-week as a cold front approaches the area by the end of the work week. SSE flow continues to increase moisture with PWATs rising into the 1.5-1.8 in. range. Isolated to scattered convection is anticipated to develop along the inland-moving sea breezes each afternoon and evening through the week. The sea breeze mergers will generally occur along the I-75 and HWY 301 corridors.

Otherwise, beneath an amplified upper ridge temperatures will be slightly above normal through next week, except at the beaches where the onshore flow will likely keep afternoon highs in the mid/upper 80s.

AVIATION /00Z SATURDAY THROUGH 00Z SUNDAY/

VFR conditions will prevail at the regional terminals through at least 07Z. Prevailing MVFR visibilities, with periods of IFR conditions, are expected at VQQ from around 08Z through around 12Z Saturday. Cumulus and stratocumulus cloud cover will likely increase from south to north after sunrise, with periods of MVFR ceilings between 2,500 and 3,000 feet possible after 13Z.
Confidence was only high enough to indicate prevailing MVFR conditions at SGJ at this time, mainly from around 14Z through around 17Z. VFR conditions should otherwise prevail, with ceilings expected to rise to 3,500 - 4,500 feet by 18Z.
Northeasterly surface winds will diminish to around 5 knots or less towards 01Z, with winds shifting to easterly at the SSI and SGJ coastal terminals before sunrise. Easterly winds will develop elsewhere after sunrise and will increase to 5-10 knots by 15Z. Surface winds will then shift to east-southeasterly towards 18Z, with speeds increasing to 10-15 knots and gusty.
Sustained speeds at SGJ will likely strengthen to 15-20 knots after 19Z Saturday.

MARINE

High pressure located over our area evening will shift offshore late tonight, with this feature strengthening near Bermuda by Saturday evening. A weak coastal trough will lift northward across our local waters late tonight and Saturday morning, developing isolated to widely scattered showers. East to southeasterly winds will then strengthen late on Saturday afternoon, likely resulting in a period of Caution conditions for the near shore waters through the evening hours. High pressure will continue to extend its axis across the southeastern states from Sunday through the middle portion of next week, keeping a persistent onshore wind flow with late afternoon and evening wind surges expected. Isolated showers and thunderstorms will be possible in this weather pattern during the early to middle portions of next week. A frontal boundary will then move over the southeastern states late next week, resulting in gradually increasing chances for showers and thunderstorms.

Rip Currents:

Persistent onshore winds will surge late on Saturday afternoon to 15-20 mph at area beaches, with moderate risk conditions through early afternoon on Saturday likely increasing to high risk conditions during the late afternoon and evening hours, as breakers build to 3- 4 feet at the northeast FL beaches and 2-3 feet at the southeast GA beaches. Similar conditions will prevail on Sunday and Monday, as onshore winds strengthen during the mid to late afternoon hours.

FIRE WEATHER

- Patchy High Dispersions Over The Weekend.

Strong ridging and high pressure shifts to the northeast this weekend, resulting in an earlier Atlantic sea breeze inland push each afternoon. Saturday will bring potential for isolated thunderstorms along the I-75 corridor and districts to the west during the early evening hours along the sea breeze. By Sunday, the gradual increase in moisture should allow for scattered chances of showers and storms across inland locations as the sea breeze moves inland. Dispersion will be near "high" levels over the weekend, especially inland, as mixing heights push above 6,000 ft. The following week will bring chances of showers and isolated storms each afternoon as the Atlantic sea breeze pushes inland.

FOG POTENTIAL AND OTHER REMARKS: Fog will be possible Saturday and Sunday mornings. Poor to moderate humidity recovery this morning will be followed by excellent recovery over the weekend.

PRELIMINARY POINT TEMPS/POPS
AMG 58 90 66 89 / 0 10 0 40 SSI 69 83 73 83 / 10 10 0 10 JAX 64 88 70 88 / 10 10 0 20 SGJ 70 87 73 86 / 10 10 0 20 GNV 65 93 70 91 / 10 30 30 60 OCF 67 91 71 90 / 10 30 30 60

JAX WATCHES/WARNINGS/ADVISORIES
FL...High Risk for Rip Currents through late Sunday night for FLZ124-125- 138-233-333.
GA...High Risk for Rip Currents through late Sunday night for GAZ154-166.
MARINE...None.