Edisto Beach, SC to Savannah, GA Marine Forecast
|Rest Of Tonight...S Winds 5 Kt. Seas 2 Ft.|
|Mon...Sw Winds 5 To 10 Kt. Seas 2 Ft.|
|Mon Night...Sw Winds 5 To 10 Kt. Seas 2 Ft.|
|Tue...N Winds 5 To 10 Kt, Becoming Ne 10 To 15 Kt In The Afternoon. Seas 2 To 3 Ft, Building To 3 To 4 Ft In The Afternoon. A Slight Chance Of Showers In The Afternoon.|
|Tue Night...Ne Winds 5 To 10 Kt. Seas 3 To 4 Ft. A Slight Chance Of Showers After Midnight.|
|Wed...W Winds 5 To 10 Kt, Becoming Nw 10 To 15 Kt In The Afternoon. Seas 2 To 3 Ft. A Slight Chance Of Showers In The Morning, Then Showers Likely With A Slight Chance Of Tstms In The Afternoon.|
|Wed Night...N Winds 10 To 15 Kt. Seas 2 To 3 Ft. A Chance Of Showers In The Evening.|
|Thu...Ne Winds 10 To 15 Kt. Seas 2 To 3 Ft.|
|Thu Night...Ne Winds 5 To 10 Kt. Seas 2 To 3 Ft. A Slight Chance Of Showers.|
|Fri...Se Winds 5 To 10 Kt. Seas 2 To 3 Ft. A Slight Chance Of Showers.|
|Fri Night...S Winds 10 Kt. Seas 2 Ft. Mariners Are Reminded That Winds And Seas Higher In And Near Tstms.|
| Area Forecast Discussion|
National Weather Service Charleston SC
1258am EST Monday Dec 6 2021
High pressure will prevail through Monday. A cold front will push south into the region late Monday night into Tuesday and linger in the area before a strong cold front pushes offshore Wednesday night. Another cold front could push offshore later this weekend.
Near Term - Until 6am This Morning
Late this evening: The fog forecast appears to be on track as several observation sites across southeast South Carolina and southeast Georgia are starting to report reduced visibilities. Unlike last night, we begin tonight with mostly clear skies except for a few patches of residual 4-6 kft cumulus and stratocumulus. The pressure gradient will again be very weak producing light to calm surface winds by the late evening hours. The prevailing low-level flow is onshore which will help to supply sufficient moisture for fog and stratus development. Model guidance shows fog developing rather quickly by late evening and settling in before high clouds increase late in the night. The forecast features patchy fog just about everywhere with areas of dense fog impacting much of southeast South Carolina all the way down to the Georgia state line closer to the coast. Confidence isn't high enough yet in the coverage and placement of dense fog to issue a Dense Fog Advisory, but it is likely some areas will need an advisory at some point. Forecast lows range from around 50 to the mid 50s at the coast.
Short Term - 6am This Morning Through Wednesday
Monday: Expect one more warm day across the Lowcountry and Coastal Empire as the wedge front retreats well to the north and the region becomes more firmly established in the warm sector ahead of an approaching cold front. After some morning fog and low clouds, temperatures will rebound quickly with highs poised to reach the mid- upper 70s away from the beaches. A weak sea breeze could reach as far inland as highway 17 in southern South Carolina and I-95 in Southeast Georgia resulting a a slight push of cooler Atlantic air inland mid-late afternoon. The string of dry weather will persist, but a weakening line of showers associated with the cold front could reach into the Allendale-Reidsville corridor by early evening bringing a risk for an isolated shower or two. Once this activity dissipates, expect a rain-free night as the front begins to backdoor to near the Savannah River by daybreak Tuesday. There is a weak, yet consistent, signal in the HREF and SREF that a little sea fog could develop off the Georgia coast by early afternoon and possibly brush Hilton Head, Tybee Island and areas farther to the south along the immediate coast during the afternoon. While widespread dense fog is not likely at this time, some reductions could occur at times if the fog does indeed form. Any sea fog should dissipate by early evening as the direction of the low- level wind field becomes less favorable. Overnight, a round of patchy fog could occur, mainly from Walterboro to Edisto Beach and points south. Lows will range from the lower 50s well inland to the upper 50s elsewhere.
Tuesday: Big chances will begin to occur Tuesday as the backdoor cold front slowly settles south of the Altamaha River during the morning. Much cooler conditions will prevail as high pressure wedges south across coastal South Carolina and Georgia. As southwest winds atop the boundary layer begin to overrun the colder surface airmass, some isentropically induced showers could occur just about anywhere. Significant rains are unlikely, but a few spots could pick up a hundredth or two. Slight chance probability of precipitation should cover this possibility. How cool Tuesday will get is a bit in question and will be closely tied to how quickly the backdoor front pushes south. Guidance has trended cooler with this forecast cycle and the forecast has been updated to reflect this, although not quite a chilly as some members would suggest. Highs will range from the upper 50s/lower 60s adjacent to the Southern Midlands and Pee Dee to the lower 70s in the Hinesville-Ludowici-Darien area where FROPA will occur the latest. Expect the front will remain to the south overnight with only the 05/12z operational GFS showing the front lifting north to the Savannah River. The ECMWF (European Centre for Medium-Range Weather Forecasts) and NAM's depiction of northeast winds through the night is favored as surface cyclogenesis over the Red River Valley is not overly strong. Even with the front holding to the south, the better risk for isolated to perhaps scattered showers will shift north with time as the better overrunning looks to retrograde back well to the west and north of the local area. Lows will range from the mid 40s north and northwest tiers to the upper 50s across the far south near Darien.
Wednesday: A cold front will finally push offshore Wednesday evening as shortwave energy traverses the Southeast States. The earlier wedge front could briefly return north bringing the warm sector into parts of Southeast Georgia before the primary cold front clears the coast. Synoptic forcing will increase with time as the aforementioned shortwave nears and somewhat of a dual jet structure evolves across the eastern Carolinas as the right entrance region of an exiting jet streak over North Carolina aligns with the left exit region of a secondary jet streak centered across the Deep South. Interesting, although model time-section show corridors of deep vertical velocities, deep saturation throughout the column does not occur with mean RH values in the mid-levels only peaking 50-65%. This will likely curtail the shower coverage somewhat even with PWATs (Precipitable Waters) maxing out in the 1.50-1.80" range. Some of the statistical guidance members have trended down with pops, including the NBM, but the scenario still looks favorable enough for a decent amount of shower activity to occur. Likely probability of precipitation of 60-70% probability of precipitation were maintained. Low probabilities for tstms were also introduced for coastal Georgia where NBM tstm probs have increased within the brief warm sector. Highs will range from the lower 60s north to the lower 70s across parts of Southeast Georgia.
Long Term - Wednesday Night Through Sunday
Rain chances will diminish Wednesday night as a the cold front pushes offshore. The front could return back to the north later in the week before a strong cold front pushes onshore later in the weekend. Expect below normal temperatures Thursday with moderating temperatures into the weekend ahead of the next cold front.
Weak wind fields will persist through tonight. Fog development is expected over land areas. Some of this fog may drift into adjacent coastal waters, particularly Charleston Harbor, so we cannot rule out Dense For Advisories later tonight.
Monday through Friday: There have been weak, but consistent signals that an area of sea fog could develop over the Georgia nearshore waters Monday afternoon. The situation looks marginal for sea fog owing to borderline water temperatures and dewpoints. Patchy fog was introduced into the forecast for now. Low-level winds veer more westerly by Monday evening which should end any risk for sea fog formation. Winds could get close to Small Craft Advisory levels along the Charleston County coast Tuesday as a backdoor front drops south and the pressure gradient tightens a bit. Right now, both speeds and the corresponding increase in seas look to remain below advisory thresholds. There are no other concerns at this time.
Tides / Coastal Flooding
Monday morning high tide: Confidence is high that the Charleston Harbor tide will peak above 7 ft MLLW so a Coastal Flood Advisory has been issued for Charleston and coastal Colleton counties from 8-11 am. The astronomical tide is 6.83 ft MLLW and current trends support enough tidal departure for a peak tide around 7.2 ft MLLW.
Perigean spring tides are expected to linger through at least Tuesday due to influences from the new moon and lunar perigee. While the wind set-up will not support significant tidal departures, minor coastal flooding will be possible again with the Tuesday morning high tide cycle. Minor salt water inundation should largely be confined to coastal portions of Charleston and Colleton Counties. Coastal Flood Advisories could be needed.
NOAA Charleston SC Office: Watches - Warnings - Advisories
GA...None. SC...Coastal Flood Advisory from 8am to 11am EST this morning for SCZ049-050.