Charleston Harbor Marine Forecast
|Today...W Winds 10 To 15 Kt With Gusts To 20 Kt, Increasing To 20 To 25 Kt With Gusts To 30 Kt Late This Morning. Waves 2 To 3 Ft.|
|Tonight...W Winds 15 To 20 Kt With Gusts To 25 Kt, Diminishing To 10 To 15 Kt After Midnight. Waves 1 To 2 Ft.|
|Sun...W Winds 10 Kt, Becoming Sw With Gusts To 20 Kt In The Afternoon.|
|Sun Night...W Winds 10 To 15 Kt With Gusts To 20 Kt.|
|Mon...W Winds 15 Kt With Gusts To 20 Kt.|
|Mon Night...Nw Winds 10 To 15 Kt.|
|Tue...W Winds 5 To 10 Kt.|
|Tue Night...W Winds 10 Kt.|
|Wed...W Winds 10 Kt.|
|Wed Night...Sw Winds 10 Kt. Unless Otherwise Noted, Waves 1 Foot Or Less. Charleston Harbor Water Temperature 54 Degrees.|
| Area Forecast Discussion|
National Weather Service Charleston SC
652am EST Sat Jan 16 2021
Cool, dry high pressure will prevail over the weekend into early next week. A weak cold front is expected to pass over the region near the end of next week.
Near Term - Through Tonight
Today: Aloft, a large upper low will cross the Ohio Valley while a sharp shortwave trough swinging around its southern periphery will move through Georgia and the Carolinas. At the surface, a sprawling area of low pressure will be positioned across an area from the Great Lakes to New England. The forecast area will be within the tight pressure gradient around this low, resulting strong westerly winds through the day. Mostly clear skies will prevail, though there will be scattered cumulus passing through mainly the South Carolina zones this afternoon. Low-level thickness progs support highs in the upper 40s inland, ranging to around and just over 50 closer to the coast. The main forecast issue today will be the strong westerly winds. Gusts will pick up by mid morning and should peak around noon through the early to mid afternoon hours. Frequent gusts to around 30 mph are expected, with gusts approaching 35 mph at times right along the coast. We should fall just short of Wind Advisory criteria in the coastal counties.
Lake Winds: Westerly winds will strengthen across Lake Moultrie this morning. Frequent gusts to or just over 25 knots can be expected over the lake and around the lake shore. A Lake Wind Advisory is in effect from 10am-6pm.
Tonight: Winds will diminish this evening with the loss of mixing and relaxing of the pressure gradient. Clear skies will prevail and a cold night is on tap. Lows are forecast to range from the upper 20s inland to the low to mid 30s closer to the coast.
Short Term - Sunday Through Tuesday
Sunday through Tuesday: Broad surface high pressure will gradually build/deepen over the Southeast throughout the period. Meanwhile, a closed H5 low will open and lift as it shifts over the Northeast Monday. Moisture associated with the trough keeps well to our north. With subsidence controlling the region, stable, dry, and rain-free conditions are expected through the period. Slightly warmer conditions are anticipated through Tuesday with max temps increasing by a few degrees each day. Low to mid 50s are expected Sunday and by Tuesday highs will be in the upper 50s/low 60s. Increased cloud coverage Sunday night will keep min temps just above freezing, and near 40F along the beaches. Clear skies thereafter will result in cooler conditions Monday night with lows in the the low to mid 30s inland and near 40F along the coast.
Long Term - Tuesday Night Through Friday
Surface high pressure will continue to dominate over the Southeast US, eventually advecting moisture from the Gulf into the Tennessee Valley. Shortwave energy and upper forcing looks to bring showers just outside the forecast area on Wednesday. However, little moisture over southeast SC/GA and surface dew points around 40F should keep any showers over the area elevated with little to no mentionable precipitation. On Thursday, a weak, slow-moving cold front approaches the region from the northwest. Showers ahead/along the front are possible Thursday afternoon into the overnight period. A second round of showers is possible Friday night/Saturday due to shortwave energy extending from an upper trough over the Northeast US. Overall, a gradual warming trend is anticipated through the period with highs climbing well into the 60s late week.
Today through tonight: Strong westerly winds will prevail today and produce hazardous marine conditions across the local waters. Confidence in gale force gusts for the Charleston County waters has increased such that a Gale Warning is now in effect through this evening. Gusts into the 35-40 knot range can be expected. Elsewhere, Small Craft Advisories are in effect and the forecast is for frequent gusts to 30 knots, including Charleston Harbor. The outer Georgia waters still stand a low chance of seeing gusts near gale force for a couple of hours this afternoon, but confidence isn't high enough to go with a Gale Warning. Conditions will steadily improve overnight as the pressure gradient relaxes. All warnings and advisories will come down at various times through the night.
Sunday through Wednesday: High pressure continues to spread into the region from the west; however, by Sunday morning winds/seas should be well below Small Craft Advisory criteria. Elevated winds will return late Sunday into Monday, with gusts near Small Craft Advisory criteria across the waters especially in the GA waters from 20nm to 60nm. W/SW winds will prevail through the period and seas will generally range from 2-4 ft with some possible 5 footers in the outer GA waters Monday evening. Thereafter, westerly winds are expected to be 15 kt or less. Seas will also decrease, with 1-2 footers across all waters by Tuesday.
NOAA Charleston SC Office: Watches - Warnings - Advisories
GA...None. SC...Lake Wind Advisory from 10am this morning to 6pm EST this evening for SCZ045.
Small Craft Advisory until midnight EST tonight for AMZ352. Small Craft Advisory until 10am EST this morning for AMZ350. Gale Warning from 10am this morning to 6pm EST this evening for AMZ350. Small Craft Advisory until 10pm EST this evening for AMZ354. Small Craft Advisory until 4am EST Sunday for AMZ374. Small Craft Advisory from 10am this morning to 10pm EST this evening for AMZ330.