Marine Weather Net

Savannah, GA to Altamaha Sound, GA including Grays Reef National Marine Sanctuary Marine Forecast


REST OF TONIGHT

W
WINDS
10
KNOTS

THU

NE
WINDS
20 - 25
KNOTS

THU NIGHT

NE
WINDS
15 - 20
KNOTS

FRI

E
WINDS
10 - 15
KNOTS

The Marine Weather Forecast In Detail:
AMZ354 Forecast Issued: 900 PM EST Wed Nov 30 2022

SMALL CRAFT ADVISORY IN EFFECT THROUGH THURSDAY EVENING
Rest Of Tonight...W Winds 10 Kt, Becoming Nw 15 To 20 Kt Later This Evening, Then N 20 To 25 Kt With Gusts To 30 Kt After Midnight. Seas 1 To 2 Ft, Building To 2 To 4 Ft.
Thu...Ne Winds 20 To 25 Kt With Gusts To 30 Kt. Seas 4 To 6 Ft.
Thu Night...Ne Winds 15 To 20 Kt. Seas 5 To 6 Ft, Subsiding To 4 To 5 Ft.
Fri...E Winds 10 To 15 Kt. Seas 3 To 4 Ft.
Fri Night...E Winds 10 Kt, Becoming Se After Midnight. Seas 3 To 4 Ft.
Sat...Sw Winds 5 Kt. Seas 3 To 4 Ft, Subsiding To 2 To 3 Ft In The Afternoon.
Sat Night...S Winds 5 Kt, Becoming W After Midnight. Seas 2 To 3 Ft.
Sun...Ne Winds 5 To 10 Kt. Seas 2 To 3 Ft.
Sun Night...Ne Winds 5 To 10 Kt. Seas 2 To 3 Ft. A Slight Chance Of Showers.
Mon...W Winds 5 To 10 Kt. Seas 2 To 3 Ft.
Mon Night...S Winds 5 To 10 Kt. Seas 2 To 3 Ft.
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Area Forecast Discussion
National Weather Service Charleston SC
857pm EST Wednesday Nov 30 2022

Synopsis
High pressure will build in across the region through Friday. A front will then shift into the area Saturday and Saturday night, and could linger in the vicinity into early next week.

Near Term - Until 6am Thursday Morning
No major changes were made for the late evening update.

Satellite, surface observations and RAP instability analysis at showed the cold front was located roughly along a Moncks Corner-Walterboro-Denmark-Claxton-Baxley line at 01/0145z. A little fog has developed just ahead of the front, but it will not last too long as surface winds will pick up quickly with FROPA.

The boundary is showing a classic bending pattern in the lee of the Southern Appalachians, typical when fronts interacts with the higher terrain of the Black Mountains of southwestern North Carolina, including Mount Mitchell. The deepest moisture has pushed offshore and with it any risk for measurable rainfall. The front will clear the coast roughly in the 10-11pm timeframe with drier and cooler conditions advecting in behind it. Once the front pushes through, expect rapid clearing to occur with clear skies prevailing overnight. Lows will range from the mid- upper 30s well inland to the upper 40s/near 50 at the beaches.

Lake Winds: Winds on Lake Moultrie are expected to surge a bit overnight as low-level cold air advection interacts with water temperatures near 60. Winds in the mixed layer look to fall just short of Lake Wind Advisory criteria, but a solid 15-20 kt along with waves 1-2 ft are expected.

Short Term - 6am Thursday Morning Through Saturday
Thursday and Thursday night: High pressure will continue building into the region Thursday, becoming centered near the Virginia Tidewater region Thursday night. The airmass will be very dry, with precipitable water values of a quarter of an inch or less through the day. The main story will be the significantly cooler temperatures. Highs are forecast to only reach the mid to upper 50s, with some low 60s possible along and south of I-16. Such temperatures would be on the order of 10 degrees below normal for early December. Also, northeast winds will be elevated due to the tight pressure gradient, making it feel even cooler. Overnight, lows will be chilly with low to mid 30s across the far inland counties, ranging to the low to mid 40s along the coast.

Friday through Saturday: The center of the high will shift out over the northwest Atlantic as a subtle coastal trough sits just offshore. As the high moves away, the low-level flow pattern will be easterly and southeasterly through Friday night, then southerly ahead of an approaching front on Saturday. Friday is currently expected to be dry, though with the coastal trough nearby we can't completely rule out some weak shower activity along the coast. For Saturday, it appears that nearly all of the precipitation will remain upstream along the front and any that approaches from the northwest late in the day will be on a distinct diminishing trend. Temperatures will moderate significantly through the period with highs increasing well into the 60s Friday and then back into the 70s Saturday.

Long Term - Saturday Night Through Wednesday
The front will drift into the area Saturday night and become oriented west to east. How far south across the area the front pushes is in question and then it appears as though it will linger int he vicinity into early next week before lifting back northward as a front. This injects some uncertainty into the forecast regarding rain chances because depending on the position of the front, the axis of rainfall could shift significantly north or south. For now it looks like the best chance of rain will come Sunday night into Monday before the front starts lifting northward taking with it the best forcing for precip. For now this is where we have the best rain chances, though they are held in the 20-30 percent range. As the positioning of the front and its movement come more into focus, rain chances could end up being higher with better confidence in the timing. Otherwise, temperatures will generally be above normal, especially once the front lifts north of the area.

Marine
Tonight: Northwest then north winds will pick up quickly behind the cold front has it pushes across the waters over the next few hours. Winds will peak 20-25 kt with gusts to 30 kt all coastal legs with 15-20 kt in the Charleston Harbor. Frequent gusts will will be very close to advisory levels for a few hours overnight, so a Small Craft Advisory has been posed for the Charleston Harbor until 4 AM. Seas will build 4-6 ft nearshore waters and 5-7 ft over the Georgia offshore water where Small Craft Advisories remain posted.

Thursday through Monday: Thursday will begin with a solid northeast surge underway as high pressure build into the region. Small Craft Advisories are already in effect for all waters outside of Charleston Harbor, and we should see a solid 20-25 knots of wind with gusts to 30 kt. Seas will increase to 4-6 feet across the nearshore waters and 6-7 feet for the outer waters. One thing to watch will be winds in Charleston Harbor, especially Thursday morning. Wind gusts will be near 25 knots for several hours and a Small Craft Advisory could be needed. Conditions will gradually improve through Thursday night as winds and seas diminish. Winds will then turn more southerly and then southwesterly into the weekend before a front drifts in from the north late in the weekend. Overall, once the advisory conditions come to an end Thursday and Thursday night, winds and seas should remain well below advisory thresholds into early next week.

NOAA Charleston SC Office: Watches - Warnings - Advisories
GA...None. SC...None.

Marine
Small Craft Advisory until 4am EST Thursday for AMZ330. Small Craft Advisory from midnight tonight to 4pm EST Thursday for AMZ350-352. Small Craft Advisory from midnight tonight to 7pm EST Thursday for AMZ354. Small Craft Advisory from midnight tonight to 1pm EST Friday for AMZ374.