textproduct: Raleigh

SYNOPSIS

An Arctic cold front currently moving offshore of the Carolinas will bring the coldest night so far this season. Behind the cold front, high pressure will build into the Southeast for the first half of the week.

NEAR TERM /TONIGHT/

As of 1225 PM Sunday...

* A Cold Weather Advisory is in effect tonight into Monday morning with widespread wind chills in the single digits overnight.

As of noon, there was not a very wide gradient of temperatures across the forecast area, but there was a noticeable difference in dewpoints - Winston-Salem had a value of 13 degrees while Clinton was 40 degrees. The back edge of the clouds was generally along the US-1 corridor and will continue to move to the east through the afternoon, with all locations except perhaps the far northeast clear by sunset. The wind will ramp up as clearing occurs, and multiple locations have already recorded wind gusts over 30 mph. The peak wind gust of 43 mph at Greensboro at 11:36am should be the maximum wind gust that will occur, primarily as skies clear and additional mixing is promoted. Temperatures may climb a degree or two when skies clear, but the cold advection is more likely to win out with temperatures generally falling through the day. This will continue through the overnight hours, with gusts finally lightening a bit after midnight. Considering winds are not expected to go calm for an extended period overnight (possibly around sunrise), radiational cooling will not be as much of a concern, but this will be the coldest night of the year so far and the coldest night in a few years for some locations. For example, the forecast low at Fayetteville is 15, which last occurred on Jan 23, 2025, 11 at Greensboro (last occurred on Jan 21, 2024), and 15 at Raleigh-Durham International Airport (last occurred Dec 26, 2022). The only record low within 5 degrees of the forecast is Fayetteville, which had its record low for December 15 of 13 degrees back in 1962. Lows everywhere will be in the teens, with wind chills dropping into the single digits. No changes are necessary for the Cold Weather Advisory, which goes into effect at 6pm and continues through 9am Monday.

SHORT TERM /MONDAY AND MONDAY NIGHT/

As of 130 PM Sunday...

* Continued cold with daytime highs 15 to 20 degrees below normal.

Weakening surface high pressure elongated across the Southeast will gradually weaken throughout the day its it slowly sinks southeast into Tues morning. The newly deposited Arctic airmass, characterized by morning low-level thicknesses nearly 60m below normal, will make for a cold afternoon with highs only reaching the mid 30s. Monday night should be another cold night, although not as cold as Sunday night. Latest forecast continues to highlight all locations falling into at least the low/mid 20s with isolated locations expected to fall into the upper teens.

A big question mark is how much orographic cirrus will develop after midnight and how long it will linger into Tues morning. The pattern is certainly favorable for widespread development across central NC, but the uncertainty stems from the amount of available mid/upper level moisture to lift is it shifts across the Ohio Valley and into the Mid-Atlantic. Only changes to the forecast were to trend slightly cooler (mid/upper teens) across the Sandhills and central/southern Coastal Plain where probabilities of mostly clear skies are highest; also will be closer to the surface high center and more likely to efficiently radiationally cool.

LONG TERM /TUESDAY THROUGH SUNDAY/

As of 130 PM Sunday...

* Continued cold Tues morning, but warming trend expected Tues through Thurs night.

* Forecast confidence increasing for Thurs into Fri morning with our next precipitation chances.

A compact shortwave shifting across the Great Lakes and Northeast Thurs into Fri will be embedded within predominantly zonal flow aloft and will drive our next precipitation chances. The forecast trend over the past 24 hours has been a more amplified wave among almost all available deterministic guidance. This is now resulting in 60 to 100m H5 height falls across central NC as a plume of anomalous moisture (0.75 to 1" PWAT) spreads into the area. Light precipitation will begin to spread northward as a warm front lifts through the area Thurs morning through the afternoon hours. Expect mostly increasing cloud cover during this time, but light rain will be possible as moisture return off the Atlantic begins.

Better rain chances will be Thurs night into Fri morning as the precipitation character changes to more mixed character nature as deterministic guidance suggests a plume of > 100 MUCAPE peels up into/near central NC. Surface based parcels appear unlikely at this time as central NC does not tap into true maritime moisture (dew points > 60 degrees). This instability may only act to increase rainfall totals a bit, but probability of > 1" in 24 hours is less than 5%. Most likely range from the grand-ensemble is between 0.25 and 0.75".

AVIATION /00Z MONDAY THROUGH FRIDAY/

As of 638 PM Sunday...

24 hour TAF period: VFR conditions are expected through the TAF period. The primary concern will be wind gusts through 06z. A forecast of 15 to 30 kt at all terminals, and with strong cold advection, the gusts are forecast to diminish near sunrise.

Outlook: VFR conditions are expected through much of the outlook period, although restrictions are expected in widespread light rain Thursday and Thursday night.

RAH WATCHES/WARNINGS/ADVISORIES

Cold Weather Advisory from 6 PM this evening to 9 AM EST Monday for NCZ007>011-021>028-038>043-073>078-083>086-088-089.