textproduct: NWS Wilmington

WHAT HAS CHANGED

Updated the aviation discussion below for the 12Z TAFs. Otherwise, no major changes coming down the track as we approach 7 AM EST.

KEY MESSAGES

1) Small Craft Advisory in effect for the coastal waters from Surf City, NC to South Santee River, SC out 20 nm until 7 AM EST Tuesday.

2) Cold air damming wedge allows for a cool start to the week.

3) Unseasonably warm temperatures from the midweek to the weekend.

KEY MESSAGE 2

Cold air damming wedge allows for a cool start to the week.

As we approach 1 AM EST, the "wedge front" is starting to enter the Cape Fear region and NC coastal plain from the northeast, as seen very clearly on radar and satellite. Northeasterly winds have just begun at KILM, and will overspread the area over the next few hours. This northeasterly flow will bring a thin layer of cool air to the region, along with plenty of cloud cover to boot.

Even as this event unfolds, guidance is still having trouble painting how the temperatures will set up this afternoon. NBM kept this afternoon's highs much too warm, which is par for the course. Members of the HREF are starting to sniff it out better, so those values were blended into this afternoon's temperature forecast. Think there will be a temperature gradient set up across the area, ranging from the lower 50s across the Pee Dee and NC coastal plain to the lower 60s in the southern parts of the Grand Strand. Can't rule out the upper 40s in those cooler spots along the northern periphery of the area, as outlined by the NAM. Didn't want to go quite that extreme just yet (such that it is).

Elsewhere, while the increased moisture should just manifest in low cloud cover, wouldn't be surprised if some isolated mist or drizzle comes into play this this afternoon and into tonight, especially over parts of southeast NC.

KEY MESSAGE 3...Unseasonably warm temperatures from the midweek to the weekend.

Mid level ridge initially over the eastern Gulf/Florida Tuesday shift eastward from Wednesday onward. At the surface high pressure will develop offshore though it won't be particularly strong or well defined especially at first. A warm season-like pattern, the resulting southwesterly flow into the Carolinas will lead to highs that are some 10-15 degrees above climatology. In addition to the WAA the moistening that occurs will bring low temperature-limiting dewpoints that could foster nighttime lows that are even more elevated above climo, 20 degrees in some cases. With dewpoints so high we could be set up for a long duration sea fog event. The mid level ridging will shunt any disturbances that could trigger precipitation well to our north.

AVIATION /12Z MONDAY THROUGH FRIDAY/

Mostly MVFR throughout the 12Z TAF period. IFR ceilings overnight have stabilized to right around 10,000-12,000 ft. Ceilings look to lift slightly as the day wears on, but still stick within MVFR range. Northeasterly flow sticks around throughout the period under a stout cold air damming wedge. IFR ceilings may show up again at KILM towards the end of the period.

Extended Forecast....Flight restrictions continue into Tuesday morning. Conditions gradually improve back to VFR throughout the day Tuesday. From there, may some flight restrictions each night due to fog. Low confidence in showers and storms Friday afternoon.

MARINE

Through Tonight...Small Craft Advisory in effect for the coastal waters from Surf City, NC to South Santee River, SC out 20 nm until 7 AM EST Tuesday. CAD wedge starting to move in from the northeast, which will bring a stiff northeasterly wind through tonight. Gusts may go up to 30 kts at times, particularly before noon EST today. Seas at 1-2 ft for now, but will gradually escalate to 4-6 ft throughout the day.

Tuesday through Friday... On Tuesday the center of high pressure moves eastward from being centered over land to being centered offshore. It will remain located there for the remainder of the period in a pattern more typical of the warm season. This also weakens the gradient allowing for a slight decrease in wave height, the 5 footers dropping out. Despite the gradient remaining weak a very long easterly fetch will develop on the southern and western peripheries of the high. Most of the resulting swell energy will be directed towards FL/Bahamas but just enough will round the high to keep seas generally in the 3-4ft range with increasing periods to 8 or 9 seconds.

Sea surface temperatures are still in the 50s. From Wednesday onwards dewpoints will be in the 60s, possibly leading to a prolonged sea fog.

ILM WATCHES/WARNINGS/ADVISORIES

NC...None. SC...None. MARINE...Small Craft Advisory until 7 AM EST Tuesday for AMZ250-252-254- 256.