Charleston Harbor Marine Forecast
|Rest Of Today...Ne Winds 5 Kt, Becoming S 5 To 10 Kt.|
|Tonight...S Winds 5 To 10 Kt.|
|Tue...S Winds 5 To 10 Kt. A Chance Of Showers With A Slight Chance Of Tstms.|
|Tue Night...S Winds 5 To 10 Kt. A Chance Of Showers With A Slight Chance Of Tstms.|
|Wed...S Winds 5 To 10 Kt. A Chance Of Showers. A Slight Chance Of Tstms In The Morning, Then A Chance Of Tstms In The Afternoon.|
|Wed Night...Sw Winds 5 To 10 Kt. A Chance Of Showers And Tstms, Mainly In The Evening.|
|Thu...S Winds 5 To 10 Kt. A Chance Of Showers And Tstms.|
|Thu Night...Se Winds 5 To 10 Kt. A Chance Of Showers With A Slight Chance Of Tstms.|
|Fri...Se Winds 5 To 10 Kt. A Chance Of Showers And Tstms.|
|Fri Night...S Winds 5 To 10 Kt. A Slight Chance Of Showers And Tstms. Mariners Are Reminded That Winds And Waves Higher In And Near Tstms. Unless Otherwise Noted, Waves 1 Foot Or Less. Charleston Harbor Water Temperature 77 Degrees.|
|Area Forecast Discussion|
National Weather Service Charleston SC
946am EDT Monday May 21 2018
Synopsis: The region will remain between Atlantic high pressure and broad low pressure to the west. This pattern should support south winds through most of the week, yielding warm and moist conditions.
Near Term - Until 6pm This Evening
Subtropical ridging from the east will hold form today as weak shortwave energy meanders along the eastern Gulf coast. Modified forecast soundings are not overly unstable today with a well defined H7 theta-e minimum centered right over Southeast South Carolina and Southeast Georgia. This will essentially cap off the atmosphere and the potential for deep convection despite highs warming into the lower-mid 80s. The various CAMs are consistent in developing isolated, low-topped showers ahead of the sea breeze and with sufficiently deep low-level moisture in place, this can not be completely discounted. A few coastal showers could move inland this morning, but activity over the Atlantic should diminish as low-level convergence shifts west to/ahead of the sea breeze. Plan to drop mentionable probability of precipitation for the coastal counties and just include 20-30% probability of precipitation across the interior. 30% probability of precipitation along with a mention of a slight chance of tstms were clustered across the far southwest Georgia zones where guidance shows deeper moisture and weaker mid-level capping.
Short Term - 6pm This Evening Through Thursday
Tonight: Surface high pressure centered over Bermuda will build across the forecast area tonight. In addition, slight increases in H5 heigheights are expected as mid level low drifts west across the Deep South. Forecast sounding across the CWA indicate that a significant subsidence inversion will build around H850. Given little to no surface instability and forcing, I will indicate decreasing values of SCHC PoPs overnight. Low temperatures should verify well in the upper 60s to around 70 degrees.
Tuesday through Thursday: The area will remain between Atlantic high pressure to the east and low pressure to the west. A cold front will approach from the north Wednesday night before stalling out just north of the area. This pattern will maintain the tropical air mass in place and lead to higher than normal rain chances, especially each afternoon and evening. In general we think the highest chances will be inland near the better moisture, instability and forcing. Some spots could pick up over an inch. No significant flooding or severe weather is anticipated at this time. Temperatures will generally be near to above normal, especially lows
Long Term - Thursday Night Through Sunday
High pressure pushing southeast from the Ohio Valley/Mid-Atlantic region will combine with Atlantic high pressure as surface low pressure tries to organize slightly in the central Gulf of Mexico. The low should move toward the north-central Gulf coast and this will continue to feed tropical moisture into the local area leading to high rain chances especially each afternoon/evening. We continue to discount the GFS which indicates a secondary low move north along the Southeast U.S. coast as it remains an outlier. Temperatures should stay near to above normal.
Today: Large high pressure centered over Bermuda will gradually build west over the region through tonight. Southeast winds will continue through today and tonight, speeds remaining between 10 kt or less. Wave heigheights are forecast to range from 2-4 ft within 20 NM to 4-5 ft beyond 20 NM.
Tuesday through Saturday: The area will remain between low pressure to the west and high pressure to the east. No significant wind concerns, however seas will be elevated near Small Craft Advisory levels close to the Gulf Stream into Tuesday and again starting Friday night
NOAA Charleston SC Office: Watches - Warnings - Advisories
GA...None. SC...None. MARINE...None