textproduct: NWS Wilmington

SYNOPSIS

Arctic high pressure keeps the cold air around through Saturday. High pressure will move off the coast by Sunday as a cold front approaches. Rain chances increase into next week as a wave of low pressure moves up the Southeast coast, potentially bringing some good rain Tuesday. A dry period is expected behind this disturbance.

NEAR TERM /THROUGH FRIDAY/

Quiet but cold through the near term. A large 1030 mb high will build in from the west behind yesterday's cold front, the high being driven by a large 994 low in eastern Canada. By daybreak 850 mb temperatures will be below 0C which in a radiational cooling setup can support some pretty notable cold. We do maintain a few knots of wind however and forecast soundings do not show the classical surface-based inversion of a rad night. Continued CAA tomorrow will bring highs that struggle to hit 50, a solid category below our coldest climatological highs.

SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/

High pressure sinks its teeth deeper into Appalachia Friday night. No doubt that Friday night looks cold, with lows easily dipping down into the low-to-mid 20s for most, sans upper 20s at the coast. Biggest question has been the debate on radiational cooling for that night, and how that may impact the apparent temperatures. I actually brought down the temperature forecast by a degree or two in some spots, as the ADJMAV guidance has handled temperatures well lately, and is sniffing out a cooling trend than what the NBM suite suggests (not that this is surprising really). Even though some apparent temperatures may dip down into the teens just before sunrise Saturday morning, especially in the traditional cool spots in parts of Bladen and Pender Counties, this still doesn't look like Cold Weather Advisory territory.

Arctic air still commands the area, with highs Saturday only reaching the upper 40s. A perfect day for hot chocolate when you're out Christmas tree shopping.

The very slightest hints of onshore flow start to return Saturday night, as the surface high starts to push offshore of the mid- Atlantic coast. Ultimately, the flow isn't deep enough to produce much of a difference in temperatures just yet. Lows Saturday night near or just below freezing for most, while they remain above freezing at the coast.

LONG TERM /SUNDAY THROUGH THURSDAY/

Southwesterly flow deepens Sunday underneath a jet streak that pushes into the mid-Atlantic region and New England. Suddenly, temperatures spike above normal just as quickly as they sunk below normal. Moisture increases ahead of another cold front, which is due to move through Sunday night into early Monday morning. This brings the next chance of showers to the area, which lows Sunday night in the low-to-mid 40s. Said front stalls offshore, lingering through at least midweek.

As is tradition, multiple centers of low pressure form along the stalled out front. Conveniently, this coincides with another shortwave that deepens aloft, allowing for another deep jet to sweep through the Deep South Tuesday into Wednesday. This will help the dynamics of the surface low. Increasing confidence of a stout low forming in the Gulf and dragging northeastward through Georgia and the Carolinas Tuesday. Even for being several days out, this is one of the better systems I've seen recently, and could hopefully give us some good rain. However, guidance is quite messy concerning the track of the low, which will mean a world of difference in temperatures, rainfall amounts, etc. If it tracks closer to the coast, that would mean warmer temperatures and more rainfall. If it tracks more over inland Georgia and the Carolinas, that would mean cooler temps and lower rainfall amounts (except the Pee Dee region, perhaps). One other thing to note that surprised me a bit is that even the 99th percentile of SBCAPE only went up to 250 J/kg. Given the uncertainty in other parts of the forecast, I figured some of the other thermodynamic parameters would be quite volatile, but that remains to be seen.

Read: Lots of uncertainty. Check back later.

After whatever Tuesday ends up being, look for a drying trend and temperatures below normal for early December.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

VFR as high pressure builds from the west. Northwest winds will grow lighter tonight and remain diminished tomorrow.

Extended Forecast...Brief sub-VFR possible Monday due to scattered showers. Much higher confidence in flight restrictions by Tuesday due to a stout low pressure system bringing SHRA to the area.

MARINE

Through Friday...Large high pressure will be spilling into the eastern U.S. through the near term. There won't be much change through the near term as the gradient will be maintained by not only the large high to the NW but also a slow moving low in eastern Canada. Seas will be choppy as they will be composed primarily of the wind chop. The offshore direction will keep the largest of these outside of the forecast zones and no headlines are expected.

Friday Night through Tuesday...Northwesterly winds at 10-15 kts gradually veer to the northeast through Saturday, with seas generally at 1-3 ft. Onshore flow builds in Sunday ahead of another frontal system that will move through the area Sunday night. Gradient winds are on the rise, with winds settling in out of the northeast at 15+ kts by Monday, and seas escalating to 2-4 ft. Finally, a stout low exits the Gulf and moves through Georgia and the Carolinas Tuesday (lots of uncertainty regarding the track of this low). Either way, winds quickly veer to the SSW by Tuesday, with winds and seas easily hitting Small Craft Advisory criteria.

ILM WATCHES/WARNINGS/ADVISORIES

NC...None. SC...None. MARINE...None.