Marine Weather Net

Charleston Harbor Marine Forecast


TODAY

E
WINDS
10
KNOTS

TONIGHT

S
WINDS
15 - 20
KNOTS

SUN

S
WINDS
20 - 25
KNOTS

SUN NIGHT

W
WINDS
15
KNOTS

The Marine Weather Forecast In Detail:
AMZ330 Forecast Issued: 605 AM EST Sat Feb 15 2025

SMALL CRAFT ADVISORY IN EFFECT FROM THIS EVENING THROUGH SUNDAY MORNING ...GALE WATCH IN EFFECT FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON...
Today...E Winds 10 Kt, Becoming Se With Gusts To 20 Kt Late This Morning. A Slight Chance Of Showers Late This Morning. A Chance Of Showers Late.
Tonight...S Winds 15 To 20 Kt With Gusts To 25 Kt. Waves 1 To 2 Ft. A Chance Of Showers, Mainly In The Evening.
Sun...S Winds 20 To 25 Kt, Becoming Sw 15 To 20 Kt In The Afternoon. Gusts To 35 Kt. Waves 2 To 3 Ft. Showers With A Slight Chance Of Tstms.
Sun Night...W Winds 15 Kt With Gusts To 20 Kt.
Mon...Nw Winds 10 To 15 Kt With Gusts To 20 Kt, Becoming N 5 To 10 Kt In The Afternoon.
Mon Night...N Winds 5 Kt.
Tue...Ne Winds 10 Kt.
Tue Night...E Winds 10 Kt. A Slight Chance Of Showers.
Wed...E Winds 10 To 15 Kt. Showers.
Wed Night...N Winds 10 To 15 Kt. Showers Likely. Winds And Waves Higher In And Near Tstms. Unless Otherwise Noted, Waves 1 Foot Or Less. Charleston Harbor Water Temperature 55 Degrees.
SHARE THIS PAGE:           
Area Forecast Discussion
National Weather Service Charleston SC
706am EST Sat Feb 15 2025

Synopsis
A warm front will lift into the area today. A strong cold front will impact the area Sunday, followed by high pressure. Another system could impact the area around the middle of next week.

Near Term - Through Tonight
At sunrise, IR satellite indicated expanding cloud cover across the forecast area. High resolution guidance indicates that an inverted surface trough off the coast will push inland by late morning, as a sea breeze. In the wake of the boundary, winds should turn from the SE and dewpoints should rise. The forecast update will feature increase in hourly sky cover and adjustments to hourly temp, dewpoints, and wind.

Today: A mid-level weak ridge will be centered overhead for the majority of the day, meanwhile a warm front parked just south begin to lift back northward across our area allowing temperatures to reach into the upper 60s in SE South Carolina and low 70s. Isentropic lift associated with this front will keep the day mostly cloudy. At the surface, remnants of Cold Air Damming (CAD) remain from the shallow cool wedge, but will quickly erode as the front pushes through the area. Northeasterly winds quickly shift southeasterly as the front passes through. Scattered showers are forecast to develop through the day in response to the aforementioned isentropic lift and chance Probability of Precipitation were kept in the forecast for the morning through the afternoon. Low Quantitative Precipitation Forecast associated with these PoPs, with 0.1 inches or less by the end of the day.

Tonight: The upper-level trough situated over the central CONUS will traverse eastward and deepen overnight as an attendant cold front approaches the forecast region from the west. Southeasterly winds will begin to surge ahead of the front, and conditions will become quite breezy overnight. Due to strong southerly flow, lows will be 10 to 15 degrees warmer than the night before, with lows in the upper 50s/low 60s.

Short Term - Sunday Through Tuesday
Sunday: A strong cold front is expected to move through the area along with a line of convection that will rapidly move across the forecast area earlier in the day. Instability will be lacking with SBCAPE just 100-300 J/kg at its peak, but deep layer bulk shear of 60-80 kt will be present. Storm Prediction Center continues with a MRGL risk for severe thunderstorms for the entire area, mainly to account for the strong shear and dynamics with the upper trough. We maintain slight chance for thunder, and there still could be some stronger showers/storms that produce strong/damaging straight line wind gusts, especially between mid morning through early afternoon. Mild temperatures are forecast, in the low/mid 70s, and breezy southerly winds ahead of the front shifting to westerly in the afternoon. Wind gusts could reach up to 35 mph most places, strongest along the SC coast where 40-45 mph are certainly possible. A Wind Advisory could be needed for a few counties. Additionally, winds over Lake Moultrie could peak around 35-40 kt which will eventually be covered by a Lake Wind or Wind Advisory. By Sunday night, the front will be well east of the area with strong arctic high pressure building from the northwest. Temperatures will quickly drop with strong Cold Air Advection well underway. We are forecasting lows to plummet to the low/mid 30s west of I-95, and upper 30s to lower 40s eastward to the coast.

Monday and Tuesday: High pressure will prevail at the surface along with quasi-zonal flow aloft. Under sunny skies Monday, highs will only reach the mid to upper 50s, and then rebound quickly Tuesday back toward normal in the low to mid 60s. Monday night will be another cold night with min temps in the low to mid 30s inland and low to mid 40s along the coast.

Long Term - Tuesday Night Through Friday
Another strong cold front could impact the region Wednesday. Still too soon to assess the severe potential, but looks to be another high shear/low CAPE scenario with little in the way of instability. Blended model guidance was quite high that far out with PoPs, but collaborated forecast went with likely to low end categorical. The main concern for this period will be the very cold/arctic high pressure that will dominate at least through the end of the week. Lows in the mid 30s to lower 40s Wednesday night could then possibly drop into the mid 20s to lower 30s both Thursday and Friday night, which would be colder than it has been since last month.

Marine
Today And Tonight
As high pressure shifts offshore overhead, northeasterly winds quickly shift southeasterly as a warm front lifts northward across Atlantic waters. With seas 5-7 ft in the outer Georgia waters, a Small Craft Advisory remains in place. Ahead of the approaching cold front, southeasterly flow surges and the gradient really tightens up by the evening. Expect southeasterly winds of 15-20 kt with gusts up to 25-30 kt at all marine zones. Small Craft Advisories issued for the nearshore South Carolina and Georgia waters beginning at 7PM tonight. In addition, a Small Craft Advisory issued for the Charleston Harbor starting at 11PM tonight. Expect seas 4-6 ft over the nearshore waters and 6-8 ft over the outer Georgia waters.

Sunday through Thursday: A strong cold front will push across the waters early in the day Sunday along with a line of quick-moving convection and strong southwest winds. Gale Watches are in effect for all marine zones, including the Charleston Harbor, Sunday morning until Sunday evening. A few stronger showers/storms are possible with dangerous gusts 50 kt or greater, mainly during the mid morning and mid afternoon time frame. Seas look to peak around 6- 10 feet Sunday afternoon. The front then passes east of the waters by Sunday evening, however Small Craft Advisory conditions are likely to remain through Sunday night/early Monday. High pressure will then build over the region Monday through Tuesday with no highlights/concerns expected. High pressure will move east of the waters Tuesday night and Wednesday ahead of yet another front. Southerly winds increase during the end of the period, with the increasing potential for Small Craft Advisories Thursday for 25 kt gusts and 5-7 ft seas.

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

Marine
Small Craft Advisory from 11pm this evening to 7am EST Sunday for AMZ330. Gale Watch from Sunday morning through Sunday afternoon for AMZ330. Small Craft Advisory from 7pm this evening to 7am EST Sunday for AMZ350-352-354. Gale Watch from Sunday morning through Sunday afternoon for AMZ350-352-354-374. Small Craft Advisory until 7am EST Sunday for AMZ374.