Surf City to Cape Fear, NC out 20 NM Marine Forecast
|Rest Of Today...Ne Winds 10 To 15 Kt. Seas 2 To 3 Ft.|
|Tonight...E Winds 10 To 15 Kt. Seas 2 To 3 Ft.|
|Mon...E Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas 3 To 4 Ft. A Slight Chance Of Tstms. A Slight Chance Of Showers In The Morning, Then A Chance Of Showers In The Afternoon.|
|Mon Night...E Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas 3 To 4 Ft. A Slight Chance Of Tstms. A Chance Of Showers, Mainly In The Evening.|
|Tue...E Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas 3 To 4 Ft. A Chance Of Showers. A Slight Chance Of Tstms In The Morning, Then A Chance Of Tstms In The Afternoon.|
|Tue Night...Se Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas 4 To 5 Ft. A Chance Of Showers And Tstms.|
|Wed...S Winds 10 To 15 Kt. Seas 4 To 5 Ft. Showers Likely With A Chance Of Tstms.|
|Thu...Nw Winds 10 To 15 Kt, Becoming N. Seas 3 To 4 Ft. A Chance Of Showers Through The Day. Winds And Seas Higher In And Near Tstms.|
| Area Forecast Discussion|
National Weather Service Wilmington NC
936am EDT Sunday September 19 2021
High pressure will persist along the East Coast through Tuesday. Unsettled weather will develop mid-week as an occluded front lifts across the area. A strong cold frontal passage will occur Thursday, followed by high pressure and cooler temperatures for the late week period.
No significant changes were needed to the forecast this morning. 12z soundings from MHX and CHS showed enough dry air aloft to prevent more than one or two very isolated showers across South Carolina.
Near Term - Through Monday
Upper-level ridge axis and surface high pressure will move across the area on Sunday. NE flow will become easterly and SE throughout the day with the steady eastward progression of the highs over the northeastern US. Substantial dry air above the boundary layer will advect southward throughout the day as patchy areas of morning fog and lifting stratus give way to mostly clear skies across the area. As the center of high pressure moves eastward throughout the day, a boundary of dry continental air over southeastern NC will be in contrast to a persistent moist air mass over central SC (portions of which could nose into northeastern SC later in the day). These areas also being removed from the upper ridge axis may allow a stray shower or two. For now, rain chances have been kept south of the area as the latest model runs show the dry air advancing into extreme northeastern SC. Hi-res models are also coming into agreement with little to no precipitation across the south-western counties. This is also corroborated with the weak lapse rates seen in the observed soundings from the neighbors. Highs similar to yesterday, upper 80s for most.
Drier air begins to retreat on Monday as high pressure shifts further offshore and column flow becomes more southeasterly, tapping into the Gulf moisture. Shower chances increase from south to north during the afternoon; areas to our south on Sunday should be a good preview of what to expect. Highs in the mid to upper 80s. Stratus may become a concern Sunday night into Monday morning with the onshore flow and a mid-level inversion trapping moisture overnight.
Short Term - Monday Night Through Tuesday Night
Mid-level dry air will hold on Monday night into Tuesday associated with a high- amplitude ridge axis aligned just off the eastern seaboard. The surface high will shift off the New England coast, and continue to push low-level Atlantic moisture into the eastern Carolinas. As the 500 mb ridge shifts east, deeper Gulf moisture will surge northward ahead of a digging 500 mb shortwave which will sweep towards the Mississippi River Valley Tuesday night. There are signals/agreement in GFS/ECMWF (European Centre for Medium-Range Weather Forecasts) that a significant precipitation event could be setting up for the SC coast Tuesday-Tuesday night. Time-height cross sections show the column becomes saturated on Tuesday, with increasing flow off the Atlantic from the surface through about 400 mb. Onshore flow will keep high temps on Tuesday near climo, although if widespread precipitation develops, could easily stay a category lower. Nighttime lows will be propped up above climo, as dewpoints remain in the upper 60s to lower 70s.
Long Term - Wednesday Through Saturday
Amplified trough will evolve into a closed low that will lift across the Great Lakes Wednesday night and Thursday. An associated cold front will sweep across the Carolinas Wednesday night, and models continue to suggest that it will move off the coast between midnight Wednesday night and sunrise Thursday morning. Showers/tstms along and ahead of the front should be offshore by Thursday afternoon. GFS is indicating the front stalling just to our south late week, then returning northward on Saturday, which doesn't seem unreasonable given the orientation of the front with the mid-level flow.
Through Monday Night... Building high pressure out of the northeast will promote a compressed gradient across the coastal waters today. NE winds early 10-15 knots will become easterly around 15 knots during the afternoon and evening as high pressure progresses eastward. Gusts around 20 knots today with seas building from 2-3 early to 3-4 feet this evening. High pressure strengthens on Monday with a weak frontal boundary to our south beginning to approach the area. This will maintain the compressed gradient and easterly flow will again build to 15-20 knots, isolated gusts up to 25 knots. Seas 3-5 feet.
Monday night through Thursday... Surface high pressure will be centered off the New England coast through Wednesday, resulting in onshore flow on the order of 10-15 kt. A cold front will cross the Appalachians Wednesday, and winds over the waters will veer to the south, with the cold front expected to move across the waters Wednesday night. Showers and thunderstorms along and ahead of the front will taper off Thursday, with high pressure building in Thursday afternoon and Friday. A post-frontal northeast surge of 15-20 kt is possible Thursday night. Some uncertainty for the end of the week as some models are showing the front stalling just to the south, and therefore a moderate gradient may linger over the waters.
NOAA Wilmington NC Office: Watches - Warnings - Advisories
SC...None. NC...Coastal Flood Advisory from 7pm this evening to midnight EDT tonight for NCZ107.