South Santee River to Edisto Beach, SC Marine Forecast
5 - 10
10 - 15
15 - 20
20 - 25
20 - 25
|Today...Ne Winds 5 To 10 Kt, Becoming E Late. Seas 2 To 3 Ft.|
|Tonight...Se Winds 10 Kt. Seas 2 To 3 Ft.|
|Fri...Se Winds 10 To 15 Kt. Seas 2 To 3 Ft, Building To 3 To 4 Ft In The Afternoon.|
|Fri Night...S Winds 15 To 20 Kt With Gusts To 25 Kt. Seas 4 To 5 Ft, Building To 4 To 6 Ft After Midnight.|
|Sat...Sw Winds 20 To 25 Kt, Increasing To 25 To 30 Kt In The Afternoon. Seas 6 To 8 Ft, Building To 7 To 9 Ft In The Afternoon. Showers Likely With Isolated Tstms In The Afternoon.|
|Sat Night...Sw Winds 20 To 25 Kt, Becoming W 15 To 20 Kt After Midnight. Seas 5 To 7 Ft, Subsiding To 4 To 5 Ft After Midnight. Isolated Tstms. Showers Likely, Mainly In The Evening.|
|Sun...Ne Winds 15 To 20 Kt. Seas 3 To 4 Ft.|
|Sun Night...Se Winds 5 To 10 Kt. Seas 2 To 3 Ft.|
|Mon...Se Winds 10 Kt. Seas 2 To 3 Ft.|
|Mon Night...S Winds 10 Kt. Seas 2 To 3 Ft. A Slight Chance Of Showers And Tstms. Winds And Seas Higher In And Near Tstms.|
| Area Forecast Discussion|
National Weather Service Charleston SC
318am EDT Thu Mar 30 2023
High pressure will reside over the area through Friday. A cold front will cross through the area Saturday, followed by returning high pressure into early next week.
Near Term - Through Tonight
Today: Aloft, zonal flow will prevail as low amplitude ridging gradually shifts eastward across the eastern CONUS. At the surface, high pressure will begin the day centered across western Pennsylvania but is expected to emerge just off the Mid Atlantic coast by the end of the day. The main impact this will have is to turn the low-level flow from northeasterly in the morning to be easterly to southeasterly by the afternoon. Clear skies are expected, and it should be a pleasant late March day. Low-level thickness progs support a high temperature around the low 70s at KCHS, and this seems quite attainable given plentiful sunshine. The forecast calls for highs mostly in the low 70s away from the immediate coast, with some mid 70s for interior southeast Georgia. Locations along the coastal zone will be several degrees cooler due to the onshore flow, with highs likely not getting out of the 60s for the immediate coast.
Tonight: The surface high will slip further off the East Coast and maintain a light southeasterly flow through the night. The first part of the evening and overnight should be cloud-free, but we anticipate increasing clouds as sunrise Friday approaches. This increase in cloud cover late will be a combination of mid and high level clouds from the west and low- level stratocumulus advecting in from the adjacent coastal waters. Lows will be much milder than the previous night, with temperatures ranging from the upper 40s far inland to the mid to upper 50s along the coast.
Short Term - Friday Through Sunday
Friday: Surface high pressure will be located over Bermuda with southerly flow establishing itself across the region. A warm front will sweep north with dewpoints rising into the lower 60s for all coastal zones. Low level thermal profiles will warm rather rapidly as 1000/850 mb thicknesses approach 1380 m in places across GA. Expect high temperatures in the lower 80s with winds gusting to 25 MPH at times. No precipitation is expected. Friday night, clouds will continue to increase in coverage with winds continuing to gust 20 to 25 MPH. This will keep low temperatures rather warm or in the mid 60s for most of the area.
Saturday: A potent upper level low will be located near the central United States Saturday morning with the wave well underway to becoming barotropic/ vertically stacked. When this happens, the cold front south of the wave is usually slower to clear than initially forecast. The GFS (Global Forecast System) now has the cold front faster than yesterday though, while the ECMWF, CMC, and NAM are slower. Have continued to keep the forecast advertised to this slower solution. Saturday looks windy across the region with wind gusts around 30 to 35 mph forecast with the morning hours being dry. The delayed frontal passage will also result in high temperatures in the upper 70s to low 80s across the area. Late Saturday afternoon into early evening a line of showers and thunderstorms will approach the region from the northwest. If any robust updrafts are able to get established, severe weather could be possible. By Saturday evening, a line of showers and thunderstorms will cross the region along with the cold front. Behind the cold front, winds will veer around from the northwest with precipitation coming to an end.
Lake Winds/Wind Advisory: While mixing will be tempered by warm advection atop Lake Moultrie, the lake shore will certainly experience strong and gusty winds. As a result a Lake Wind Advisory could be required at a later time. Peak wind gusts will also be right at or just below Wind Advisory criteria. For now, confidence is much higher that a Lake Wind Advisory will be needed compared to a Wind Advisory.
Long Term - Sunday Night Through Wednesday
The latest ensemble guidance continues to support a return to well above normal temperatures next week, with a chance of showers and thunderstorms each afternoon. The GEFS, GEPS, and EPS all show mid-level height anomalies of +1 to +2 SD anomalies by the middle of next week.
Sunday: Surface high pressure will center overhead with Sunday featuring the coolest temperatures of the week. The upper level pattern does show a potent subtropical jet streak overhead at this time, which usually does lend to some high clouds, but no precipitation is forecast. Expect highs in the low to mid 70s with temperatures falling off into the lower 50s Sunday night/ Monday morning.
Monday: Each successive model run, Monday looks more cloudy with increasing chances of precipitation. A southern stream closed low will begin to open up Sunday as it ejects east and shear out. The wave is forecast to open as it crosses SC/ GA Monday, but still shows a fair amount of DCVA. Latest forecast soundings now advertise overcast skies with light showers, Monday. For now we are advertising slight chance PoPs, but this may need to be adjusted upward in subsequent forecast packages.
Tuesday and Wednesday: The mid-level wave will be exiting the coast Tuesday as a potent closed low approaches the west coast of the United States. This will allow mid-level heigheights to quickly rise Tuesday into Wednesday. Latest ensemble guidance continues to show the 586 dam line reaching SC Wednesday. Expect highs in the mid 80s by Wednesday with dewpoints well into the 60s.
Today through tonight: Light northeast winds this morning will gradually turn to be easterly and 10-15 knots by the late afternoon. Overnight, not a whole lot of change other than that wind directions will veer a bit more and become southeasterly. Wind speeds should remain modest and mostly in the 10-15 knot range. Seas will mostly average 2-3 feet, with up to 4 feet possible in the outer Georgia waters.
Friday And Saturday
High pressure will translate offshore with seas and winds slowly starting to increase during the day. Winds will veer out of the south/southwest with gusts 25-30 kt over the waters by Saturday. Small Craft Advisories will likely be needed for the majority of marine zones as early as Friday night. Gale force winds are even possible across the Charleston County nearshore waters Saturday afternoon. Seas will average 4 to 8 ft.
Sunday and Monday: A cold front will push across the local waters early Sunday morning with winds and seas relaxing below Small Craft criteria by late morning. No additional marine concerns are expected through Monday.
NOAA Charleston SC Office: Watches - Warnings - Advisories