Marine Weather Net

South Santee River to Edisto Beach, SC Marine Forecast


TONIGHT

SW
WINDS
10 - 15
KNOTS

WED

W
WINDS
15 - 20
KNOTS

WED NIGHT

NW
WINDS
5 - 10
KNOTS

THU

SW
WINDS
15 - 20
KNOTS

The Marine Weather Forecast In Detail:
AMZ350 Forecast Issued: 320 PM EST Tue Jan 19 2021

Tonight...Sw Winds 10 To 15 Kt With Gusts To 20 Kt, Increasing To 15 To 20 Kt After Midnight. Occasional Gusts To 25 Kt Late. Seas 2 To 3 Ft.
Wed...W Winds 15 To 20 Kt, Becoming Nw 10 To 15 Kt In The Afternoon. Occasional Gusts To 25 Kt Early. Seas 3 To 4 Ft, Subsiding To 2 To 3 Ft In The Afternoon.
Wed Night...Nw Winds 5 To 10 Kt. Seas 2 Ft.
Thu...W Winds 10 To 15 Kt, Becoming Sw 15 To 20 Kt In The Afternoon. Seas 2 Ft, Building To 3 To 4 Ft In The Afternoon. A Slight Chance Of Showers In The Afternoon.
Thu Night...W Winds 15 To 20 Kt With Gusts To 25 Kt. Seas 3 To 4 Ft. A Chance Of Showers.
Fri...W Winds 10 To 15 Kt. Seas 3 To 4 Ft, Subsiding To 2 To 3 Ft In The Afternoon. Showers Likely.
Fri Night...Nw Winds 10 Kt, Becoming N With Gusts To 20 Kt After Midnight. Seas 3 To 4 Ft. A Chance Of Showers.
Sat...Ne Winds 15 To 20 Kt. Seas 3 To 4 Ft.
Sat Night...Ne Winds 10 To 15 Kt. Seas 2 To 3 Ft.
Sun...Ne Winds 10 To 15 Kt. Seas 2 To 3 Ft.
Sun Night...E Winds 5 To 10 Kt. Seas 3 To 4 Ft.
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Area Forecast Discussion
National Weather Service Charleston SC
342pm EST Tuesday Jan 19 2021

Synopsis
High pressure will prevail through Wednesday. A cold front is forecast to move through the region on Friday, followed by high pressure for the weekend. A stronger cold front is expected to affect the area early next week.

Near Term - Until 6am Wednesday Morning
The surface high will gradually push offshore tonight. A shortwave trough will pass by to the north, pushing a dry cold front through the area overnight. This evening, the boundary layer may partially decouple, which along with mostly clear skies should allow temperatures to drop quickly. Late this evening and overnight, however, surface winds will pick up and some mid and high clouds will overspread the area. Temps will thus only slowly fall after midnight or perhaps remain nearly steady. Lows will be in the low to mid 40s.

Short Term - 6am Wednesday Morning Through Friday
Wednesday: A shortwave will pass to our north during the morning. It's forecasted to become a strengthening trough off the coast in the afternoon, moving further away with time. Weak ridging will pass to our north overnight, with west northwest flow prevailing overhead. Surface high pressure will prevail over the Southeast, bringing dry conditions. Expect mostly sunny skies during the day, with increasing high clouds from the west overnight. Temperatures should be a few degrees above normal during the day and near normal at night.

Thursday into Friday: West northwest flow prevails in the mid- levels on Thursday, becoming westerly on Friday. At the surface, high pressure centered over the Southeast Thursday morning will shift over Southern FL and the Bahamas Thursday afternoon, then move further away into Friday. Meanwhile, a front will approach from the west Thursday, then spread across our area on Friday. Decent moisture is expected with the front, with PWATs (Precipitable Waters) approaching 1.5" by Friday. As for the shower potential, models have come into better agreement overall. Thursday morning is expected to be dry, with showers developing/overspreading the area from the west Thursday afternoon and evening. POPs really ramp up overnight, especially across our GA counties. By Friday showers will overspread the entire area. We have categorical POPs for most locations, but expect these to be raised more if forecast trends persist. Rainfall amounts should generally be 0.25-0.5" into Friday. As for temperatures, warm air advection and some breaks in the clouds should yield high temperatures in the low to maybe mid 60s Thursday. The rainfall on Friday will limit them to the mid 50s to around 60 degrees.

Long Term - Friday Night Through Tuesday
Building high pressure and drier conditions are expected Sunday/Monday in the wake of a cold front. A slightly stronger cold front will approach the area Tuesday. Temperatures should return to near normal early in the week with the cooler air mass over the area, before they begin to warm prior to the approach of the front. Showers associated with the front are likely to effect the region late Monday night through Tuesday night.

Marine
Quite conditions will continue through this evening as surface high pressure pushes offshore. A 30-35 kt low-level jet will push over the waters late tonight as a shortwave passes by to the north. Sustained winds beyond 15 nm from the SC coast could increase to 15-20 kt. Some 25 kt gusts are certainly possible but they would be restricted to far outer reaches of AMZ350. We mentioned occaional 25 kt gusts in the CWF but held off on a Small Craft Advisory at this time.

Expect elevated winds Wednesday morning with gusts to 20 kt. Gusts could approach 25 kt across the easternmost portion of the Charleston waters. But the areal coverage is small enough and the time period short enough where we won't need a Small Craft Advisory. If observations or model runs increase winds a bit, then an Advisory will be needed. Winds are expected to ease Wednesday afternoon into the overnight period. Though, they'll increase again Thursday as a cold front slowly approaches from the west. Gusts should approach 25 kt Thursday night for portions of the waters and Small Craft Advisories will probably be needed, mainly for the SC waters and the GA waters beyond 20 nm. The front is expected to move offshore late Friday, with winds/seas lowering. A secondary surge in the winds is expected Saturday as the front moves further offshore. Conditions should remain below Small Craft Advisory criteria, however. Winds/seas are expected to gradually decrease/subside Sunday.

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