textproduct: NWS Wilmington

SYNOPSIS

Much colder and drier air will build in this afternoon behind a strong cold front. Below normal temperatures should last through Monday night before returning to normal Tuesday through Wednesday. The next cold front arriving Thursday morning will be followed by more cold weather lasting through Friday.

UPDATE

Updated aviation discussion for 12Z TAFs.

NEAR TERM /THROUGH TONIGHT/

A significant pattern change will occur during this period as mid- upper troughing shifts eastward and shoves the anomalously warm air mass that has been present for the last several days offshore. Although the pre-frontal band of showers that was over the Piedmont on Saturday has largely dissipated, hi-res guidance tools suggest that some redevelopment in the form of at least widely scattered showers should occur early this morning as stronger forcing tied to a potent shortwave pivoting through the trough impinges on the abnormally warm and moist air mass. While the coverage of showers that ends up developing is in question, most locations that do see rain should see less than 0.10", with isolated spots in eastern portions of the forecast area potentially seeing between 0.10-0.25". This precip band will bring a westerly wind shift behind it by mid- morning at the coast, with the initial push of cooler and drier air coming in its wake. Insolation should be able to counteract the initial cold advection and nudge temps up 2-3 degrees through early afternoon before a stronger surge of cold advection arrives. Thus, while daily (24 hr) max temps will occur early this morning in the low-mid 60s, the daytime (sunrise-sunset) max temps should be in the upper 50s to low 60s by 12-2PM before falling. Another gusty day will be in store with west to northwest winds of 15-20 kts and gusts as high as 30-35 kts during the afternoon.

Gusty northwest winds will subside this evening, but not before dew points have fallen into the teens. Thus, a chilly night is in store with lows in the mid-upper 20s inland and around 30F near the coast. With a light NW breeze still ongoing, early morning wind chills may be as low as 20F around sunrise Monday morning.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/

This warmth of the past several days will be a fading memory by Monday as a much cooler and drier Canadian airmass covers the Southeast. 1032 mb high pressure centered across the Mid South Monday morning should weaken as it slides eastward to the Carolina coastline by Tuesday morning. Sinking air within the ridge should maintain dry weather and mostly clear skies. Model blends look reasonable for temperatures, except I went a couple degrees below the NBM near the coast Monday night as the high builds in. Good radiational cooling scenarios typically favor cooler GFS/NAM MOS numbers. Minimum relative humidity could reach 25-30 percent Monday and 20-25 percent on Tuesday, but thankfully without significant wind.

LONG TERM /WEDNESDAY THROUGH SATURDAY/

A significant amplification of the upper air pattern will occur over the eastern U.S. late this week. A strong shortwave will dive southward from Minnesota to Missouri Wednesday, carving out a narrow but deep trough over the Carolinas Thursday. Both the GFS and ECMWF show 500 mb temps dipping to -27 to -30C, at least 5C below the 10th percentile climatology and near daily record mins at MHX.

A strong surface cold front will be pushed southeastward ahead of the upper trough, likely reaching the eastern Carolinas Thursday morning. With only a short period where limited Gulf moisture could get advected northeastward ahead of the system, forecast rain chances remain quite low: 30 percent or less late Wednesday into Thursday. Strong cold advection during the day Thursday should result in breezy winds as vertical mixing brings down higher momentum air from aloft. 00z GFS soundings suggest we could see wind gusts up to 45 mph during the afternoon as profiles steepen.

Cold air should continue to build in Thursday night with 850 mb temps expected to bottom out in the -5C to -8C range, potentially supporting low temps Friday morning in the 20s all the way down to the beaches. It's too early to rule out snow flurries or snow showers Thursday night over southeastern North Carolina as there could be a band of mid level moisture whipping southeastward around the upper trough as it moves by to our north. The 00z GFS continues to show this potential, although other models show too little moisture to support clouds, let alone snow. A recent analog situation could be November 10, 2025 when a powerful upper level trough produced flurries as far south as Florence, Marion, and Myrtle Beach.

Next weekend's weather pattern has low confidence as ensemble spread remains large and the next upper trough approaching from the west on Saturday is depicted in very different ways by the latest operational GFS/Canadian/ECMWF runs. Our forecast will keep Saturday dry for now with near normal temperatures.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

The westerly wind shift has just crossed the western terminals as of this writing, effectively ending precip chances there. Radar indicates showers are developing just east of these sites, warranting TEMPOs for brief MVFR vis and cig impacts at the coastal sites through this morning. Otherwise, gusty west to northwest winds will be the dominant hazard for aviation today with gusts peaking in the 25-35 kt range this afternoon, highest away from the immediate coast. Gusts will subside fairly rapidly after sunset, although a steady northwest wind will continue through the night. Outside of a brief window for MVFR cigs associated with the northwesterly wind shift boundary later this morning into the early afternoon, VFR will prevail at all sites after the initial westerly wind shift.

Extended Forecast...VFR conditions prevail through Wednesday. Restrictions are possible again with arrival of the next cold front Wednesday night and Thursday.

MARINE

Through Tonight...Breezy southwest winds around 20kts will turn westerly by late morning, then northwesterly this afternoon. Speeds will increase to around 25-30 kts in tandem with the northwesterly wind shift, resulting in SCA conditions from late this morning through much of tonight. Seas of 3-5 ft (with some 6ft waves possible in the waters around 15-20nmi southeast of Cape Fear) will peak in the offshore flow this afternoon and evening before subsiding with the decreasing winds through the rest of tonight to around 1-3 ft. Wind waves will be the dominant contributor to the wave spectrum.

Monday through Thursday Night...Breezy north to northeast winds as high as 20 knots Monday morning should diminish quickly during the afternoon as high pressure builds across the Carolinas from the west. The center of the high should reach the Carolina coastline late Monday night, accompanied by wind speeds less than 10 knots which should last through Tuesday. Coinciding with this lull in wind will be a lack of any significant swell, so expect a glassy ocean with wave heights 1 foot or less.

The high should weaken and shift to our south Tuesday night allowing wind directions to turn southwesterly. Winds will increase during the day Wednesday ahead of an approaching cold front. Wind speeds Wednesday Night could reach 20-25 knots which would trigger a Small Craft Advisory if reached. Seas could build to 5-7 feet. There is still some spread in models about when the front itself will reach the area: yesterday's 12z Canadian was the fastest showing a pre- dawn Thursday morning frontal passage, but most other models are 4-8 hours later. Winds should veer northwesterly Thursday night and remain quite strong.

ILM WATCHES/WARNINGS/ADVISORIES

NC...None. SC...None. MARINE...Small Craft Advisory from 10 AM this morning to 7 AM EST Monday for AMZ250-252-254-256.