Marine Weather Net

South Santee River to Edisto Beach, SC Marine Forecast


TODAY

N
WINDS
15 - 20
KNOTS

TONIGHT

N
WINDS
15 - 20
KNOTS

TUE

N
WINDS
15 - 20
KNOTS

TUE NIGHT

N
WINDS
20 - 25
KNOTS

The Marine Weather Forecast In Detail:
AMZ350 Forecast Issued: 317 AM EST Mon Jan 20 2020

SMALL CRAFT ADVISORY IN EFFECT UNTIL 10 AM EST THIS MORNING
Today...N Winds 15 To 20 Kt With Gusts To 30 Kt Early. Seas 4 To 5 Ft, Subsiding To 3 To 4 Ft This Afternoon.
Tonight...N Winds 15 To 20 Kt With Gusts To 25 Kt. Seas 3 To 4 Ft.
Tue...N Winds 15 To 20 Kt, Increasing To 20 To 25 Kt In The Afternoon. Seas 4 To 5 Ft.
Tue Night...N Winds 20 To 25 Kt With Gusts To 35 Kt. Seas 4 To 6 Ft, Building To 5 To 7 Ft After Midnight.
Wed...Ne Winds 20 To 25 Kt With Gusts To 35 Kt. Seas 5 To 7 Ft.
Wed Night...Ne Winds 15 To 20 Kt With Gusts To 25 Kt. Seas 4 To 6 Ft, Subsiding To 4 To 5 Ft After Midnight.
Thu...Ne Winds 15 Kt. Seas 4 To 5 Ft.
Thu Night...Ne Winds 10 To 15 Kt. Seas 3 To 4 Ft. A Chance Of Showers.
Fri...E Winds 10 Kt. Seas 3 To 4 Ft. A Chance Of Showers.
Fri Night...S Winds 10 To 15 Kt. Seas 3 To 4 Ft. Showers Likely.
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Area Forecast Discussion
National Weather Service Charleston SC
1232am EST Monday Jan 20 2020

Synopsis
High pressure will build in through the middle of the week, then will weaken through the rest of the work week. A low pressure system could impact the area this weekend.

Near Term - Until 6am This Morning
Clear skies will prevail. A post frontal trough will slide south through, and is followed by even stronger cold advection as winds veer around to the north. This will allow for an advective freeze to reach our inland counties around 7 or 8 am, while the coastal corridor will be in the mid or upper 30s. Given winds of 5-15 mph inland and at least 15-20 mph, wind chill values will drop as low as the mid and upper 20s late tonight and Monday morning.

Lake Winds: Conditions will close to advisory thresholds on Lake Moultrie during the overnight hours. We continue to show conditions just shy as NW and N winds reach 15-20 kt.

Short Term - 6am This Morning Through Wednesday
Monday through Tuesday night: Dry and cold surface high pressure will prevail. Our high temps will reach low to mid 40s as a mid-level trough slides over the Midwest. Low temperatures will drop to our lowest values so far this season, with our values in the upper 20s inland and low 30s along the coast. Tuesday, temps will be similar to Monday but with gusty winds, it could feel chillier. Monday night and Tuesday night, min temps are expected to be upper 20s to low 30s. At this point, the combination of winds and cold temperatures will yield wind chill values in the upper teens across most of the inland counties, just a few degrees above Wind Chill Advisory levels. If nighttime temperatures trends a bit colder and/or winds a little stronger, it is possible Wind Chill Advisory would be needed either night. Temperatures during the period may average around 15 degrees below normal.

Wednesday: The center of the mid-level low will slide over the western Atlantic during the daylight hours. As the closed low approaches a cold front, a frontal wave is expected to gradually deepen and organize over the western Atlantic. Short term models indicate that the western edge of an expansive area of precipitation is expected to brush against our outer GA waters. At this time, Probability of Precipitation over the outer GA waters will remain limited to SCHC for showers. Temperatures will begin to modify as mid-level heigheights begin to increase from the west. Using a blend of MOS, high temperatures are forecast to range within the low 50s.

Long Term - Wednesday Night Through Sunday
A large area of high pressure will become centered across the Mid- Atlantic states Thursday into Friday while a mid-level ridge axis persists along the eastern seaboard. The pattern will favor a warming trend during the second half of the week as surface winds turn more directly onshore under ridging aloft. In general, high temps should range in the upper 50s to lower 60s Thursday, then middle/upper 60s on Friday. Temps could be limited somewhat to start off the weekend once a coastal trough develops along the southern edge of high pressure, mainly due to clouds and showers drifting onshore, followed by even a greater chance of precipitation when deeper moisture advects into the region in advance of a low pressure system and associated surface cold front approaching from the west. Scattered to potentially numerous showers could persist across much of the area Friday night into Saturday before dry high pressure returns post frontal passage Saturday night and Sunday. Temps will be mild ahead of the front, remaining in the low/mid 50s Friday night, then peaking in the mid/upper 60s Saturday afternoon. Temps should return to near normal on Sunday with highs generally in the upper 50s to around 60 degrees.

Marine
Overnight: A post-frontal trough will continue to progress south through the maritime area, as arctic high pressure builds out of the northern Plains. Strong cold advection and isallobaric pressure rises that reach as much as around 1 millibar every 1-2 hours will generate NW and N winds that climb as high as 20 or 25 kt, with stronger gusts. Because of these speeds we have Small Craft Advisories in effect for all marine zones. Seas will be held down a little due to the offshore trajectories, but still as high as 3-5 ft within 20 nm and 4-6 ft on the outer Georgia wasters.

On Monday, large high pressure centered over the Midwest will build SE across region. The pressure gradient across the marine zones should support gusts in the mid 20s Monday morning, decreasing to 20kts or less during the PM. Seas are forecast to range between 2-4 ft across the nearshore waters, remaining around 6ft across the outer GA waters through mid-afternoon. Small Craft Advisories will remain in effect until mid-morning Monday and AMZ374 until 4 PM.

Tuesday through Wednesday night: Low pressure will organize and deepen offshore as a mid-level disturbance arrives from the NW. The marine zones will remain between the developing low to the east and high pressure centered to the NW. This pattern will likely yield Small Craft Advisory to marginal Gale conditions outside the CHS Harbor Tuesday through Wednesday night with gusty NE winds and building seas. Seas are forecast to peak on Wednesday between 4-7ft across the nearshore zones to around 10 ft across AMZ374.

High pressure will build over the area on Thursday and Friday, with gradually lowering wind gusts and seas. Seas above 6 ft may linger across AMZ374 on Thursday and Friday.

NOAA Charleston SC Office: Watches - Warnings - Advisories
GA...None. SC...None.
MARINE...
Small Craft Advisory until 10am EST this morning for AMZ330- 350-352-354. Small Craft Advisory until 4pm EST this afternoon for AMZ374.