
South Santee River to Edisto Beach, SC Marine Forecast
Today...Ne Winds 5 To 10 Kt, Increasing To 10 To 15 Kt Late. Seas 2 To 3 Ft. Wave Detail: Ne 3 Ft At 4 Seconds And Se 2 Ft At 10 Seconds. |
Tonight...Ne Winds 10 To 15 Kt. Seas 2 To 3 Ft. Wave Detail: Ne 3 Ft At 4 Seconds And Se 2 Ft At 9 Seconds. A Slight Chance Of Showers After Midnight. |
Wed...Ne Winds 10 To 15 Kt, Becoming N 15 To 20 Kt In The Afternoon. Seas 3 To 4 Ft. Wave Detail: Ne 4 Ft At 5 Seconds And Se 2 Ft At 9 Seconds. Showers. |
Wed Night...N Winds 15 To 20 Kt With Gusts To 25 Kt. Seas 3 To 4 Ft. Wave Detail: N 4 Ft At 4 Seconds And Se 2 Ft At 9 Seconds. Showers, Mainly In The Evening. |
Thu...Nw Winds 15 To 20 Kt With Gusts To 25 Kt. Seas 3 To 4 Ft. Wave Detail: N 4 Ft At 5 Seconds And Se 2 Ft At 9 Seconds. |
Thu Night...N Winds 15 To 20 Kt With Gusts To 25 Kt. Seas 3 To 4 Ft, Building To 4 To 5 Ft After Midnight. Wave Detail: Nw 3 Ft At 4 Seconds And E 2 Ft At 7 Seconds, Becoming N 4 Ft At 5 Seconds And Se 2 Ft At 8 Seconds. |
Fri...N Winds 15 To 20 Kt. Seas 3 To 4 Ft. |
Fri Night...N Winds 10 Kt. Seas 2 Ft. |
Sat...Ne Winds 5 To 10 Kt. Seas 2 Ft. |
Sat Night...N Winds 5 To 10 Kt. Seas 2 Ft. A Slight Chance Of Showers. |
Area Forecast Discussion National Weather Service Charleston SC 328am EST Tuesday Feb 18 2025 Synopsis High pressure will build into the area today. A coastal low will track northeastwards off the Georgia/South Carolina coast on Wednesday, with high pressure returning at the end of the week. Near Term - Through Tonight Broad surface high pressure will remain across the forecast area today. IR satellite shows a large shield of cirrus level clouds spreading east across the Deep South and Southeast U.S. ahead of mid-level trough. Cloud cover should gradually increase through the day, becoming mostly cloudy by this afternoon. H850 winds should remain from the west this morning, expected to back from the southwest this afternoon. As a result, llevel thicknesses should gradually increase across the CWA (County Warning Area) this afternoon. High temperatures are forecast to range from around 60 degrees across the CHS Tri-county to the mid 60s across extreme SE GA. Satellite water vapor this morning clearly showed the position of the jet stream, across the Southern Plains east across the mid- Atlantic states. By late tonight, the jet will pivot over the southern Mississippi River Valley and strengthen ahead of the H5 trough.Near Term - Rest Of Today Through Tonight ance shows that a surface low will organize near the Mississippi Delta late tonight. In addition, an inverted trough is expected to develop over the Gulf Stream off the GA/SC coast during the pre-dawn hours. GFS1deg view of H5 Q-vector convergence indicates that a spoke of 5 to 10 units will push across the forecast area ahead the amplifying wave tonight. The forecast will feature dry conditions through late tonight. However, isolated to scattered light showers should spread SW to NE across the region before daybreak Wednesday, supported by the synoptic scale forcing. Low temperatures are forecast to range from around 40 degrees inland to the mid to upper 40s along the coast. .SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/... By daybreak Wednesday morning, the coastal low or prefrontal trough will continue to slowly drift northwards, while the low moving across the Gulf has continued to slow with each model run. In addition, model trends have brought the track of the Gulf low further south before dissipating by Thursday morning. Despite no longer having the lift associated with the Gulf low, mid-level shortwaves arrive throughout the morning hours, which in combination with the prefrontal trough will result in widespread rain showers for the vast majority of the day. As has been the case, instability is looking to be rather meager, so not expecting any thunderstorms throughout the day. Precipitable water (PWAT) values have also come down for the day, largely due to the absence of the Gulf low, but with values remaining in the 1-1.25" range, rainfall amounts look to remain largely in the 0.25-0.75" range, highest along the coasts. As cold air begins to filter down into the region overnight, some model soundings in Berkeley county show sub-freezing boundary layer temperatures begin to emerge, though the surface layer remains well above freezing...resulting in a cold rain. With precipitation moving out of the region before the subfreezing temperature profiles arrive, not expecting any snow or freezing rain to occur. The coastal low continues to intensify Wednesday evening as it lifts northwards, with strong cold-air advection (CAA) on the backside bringing Thursday morning lows down into the upper 20s to lower 30s across SE SC, and lower to mid 30s across SE GA. Winds will be weakening as we get towards daybreak on Thursday, which should help to keep the wind chill values well above cold weather thresholds, though wind chills in the mid 20s to lower 30s will certainly necessitate warmer clothing! The rest of the day will see skies clearing allowing for afternoon temperatures to increase, though we'll likely only see mid 40s to lower 50s. Another push of cold air is expected overnight into Friday as the surface high pressure over the central US slides eastwards, with temperatures expected to dip down into the lower to upper 20s across the region. While winds will remain on the lighter side (below 10 mph), while the wind chills in the upper teens to lower 20s may require a cold weather advisory Friday morning. Ample sunshine will help bring the region back up into the upper 40s to lower 50s, but alas that remains a solid 15 to 20 degrees below normal. Long Term - Saturday Through Monday Saturday will see the aforementioned surface high pressure slide onto the Atlantic, with warmer southerly winds already bringing the region back up into the 50s and lower 60s. Deterministic guidance begins to diverge on the timing of the exiting surface high which propagates through the mid-levels, with ensemble clustering showing the main factor being the strength of the trough along the east coast. For now, populated with the NBM which adds low chances (~20%) for rain showers throughout the day on Sunday. Otherwise, the main story is the return of nice and warm temperatures in the 60s and 70s to start off next week. Marine Weak high pressure will remain across marine zones today. The pressure pattern should support northeast winds generally between 10 to 15 kts. Seas are forecast to remain between 2 to 3 ft. An inverted trough will develop over the Gulf Stream late tonight. Guidance indicates that pinched pressure gradient may develop across the nearshore waters, just west of the inverted trough. Northeast winds between 10 to 15 kts with gusts to 20 kts are forecast for the nearshore waters. Winds may remain a bit weaker across the outer GA waters. Wave heigheights should persist between 2 to 3 ft. Wednesday through Sunday: On Wednesday, a coastal low is expected to deepen across the Gulf Stream, tracking to the northeast. Winds should strengthen on Wednesday into Thursday night, with gusts around 25 kts possible outside the CHS Harbor. In addition, seas should build during the mid-week, generally between 3 to 5 ft with periods of 6 ft seas across the outer GA and possibly the Charleston County nearshore waters. Small Craft Advisories will be possible for portions of the Atlantic waters Wednesday into Thursday night. High pressure will return to the region Friday through this weekend. Winds and seas should remain below SCA (Small Craft Advisory) criteria. Climate Record Low Maximum Temperatures: February 21: KCHS: 47/2020 Record Low Temperatures: February 21: KCHS: 22/1958 NOAA Charleston SC Office: Watches - Warnings - Advisories GA...None. SC...None. Marine None. |