textproduct: NWS Wilmington

WHAT HAS CHANGED

18Z Aviation discussion updated.

Continued uncertainty with the potential winter storm this weekend.

KEY MESSAGES

- 1) Multiple Arctic fronts bring frigid air to the area, with dangerous wind chills getting down into the teens and single digits later this week.

- 2) Developing low pressure off the Southeast coast this weekend could bring winter weather and hazardous travel conditions to the area.

DISCUSSION

KEY MESSAGE 1...Multiple Arctic fronts bring frigid air to the area, with dangerous wind chills getting down into the teens and single digits later this week.

Multiple cold fronts move through this week, including one tonight, and another Thursday. While these fronts won't be bringing any precipitation, they will be reinforcing some deep Arctic air into the Carolinas. Highs Wednesday and Thursday will only get into the 40s at best, before having a chance to rebound slightly into the lower 50s in parts of the Grand Strand by Friday.

Lows over the next few nights dip well into the 20s. The traditional cold spots in parts of Bladen and Pender Counties may have wind chills in the upper teens through Thursday night.

Forecast seriously changes by Friday night. Still lots of details to figure out about this weekend's potential winter storm (see Key Message 2 below). But snow or no snow, the extreme cold is a significant story unto itself. The strongest Arctic blast yet due to arrive Friday night, sending wind chills down below 15F, where a Cold Weather Advisory may be needed. Extreme Cold Warning may be needed Saturday night, where wind chills could sink to near 0F (first time I've seen that in my 7+ years of working at this office).

Wind chills very slowly recover going into early next week, but still remain easily under 15F.

Now is the time to prepare for this extreme cold, remembering to protect the 4 Ps: people, plants, pets, and pipes. Go to weather.gov/safety/cold-before to learn more on how to prepare.

KEY MESSAGE 2:...Developing low pressure off the Southeast coast this weekend could bring winter weather and hazardous travel conditions to the area.

Regarding the setup for this weekend, not much has changed. Deep, cold air over land paired with Gulf moisture from an offshore low could bring winter weather to our CWA. With this recent run of guidance I'm not seeing much change in the nature of the airmass, the column below freezing which should lead to a purely snow setup. The issues are coming from the discrepancies in the track of the low. Too far away, not enough moisture for snow, big bust. Any closer, several inches become possible. I'm not seeing any consistency in the recent runs, so confidence on snowfall totals will remain low at this time. Trends I'm noticing in the recent NBM run is less snow, particularly for the coast of NE SC, but with the current forecast uncertainty I'm not sure if this is the start of a meaningful trend or not. Future runs should make this more clear.

In terms of timing, the start of the event looks to be as early as Friday night as the low pushes in from the SE. The low will move closest to our CWA through Saturday, where snowfall rates will be highest. For now, the event should be over by Sunday as the low travels to our NE.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

Nothing but VFR through the 18Z TAF period. WSW winds may get up to 10 kts later this afternoon, particularly at KFLO and KLBT. Winds come back towards 4-6 kts by sunset this evening. Winds gradually veer to the NNE late tonight, and may calm for a few hours inland. Gradual backing to the WNW expected after sunrise Wednesday morning, with a more cirrus clouds streaming in.

Extended Forecast...VFR to dominate through Friday. Increasing confidence on more flight restrictions this weekend with a potential winter storm, but the type of precipitation is up in the air between rain and snow.

MARINE

Through Wednesday...Gradient winds out of the W to WSW on the rise as a dry cold front moves through the area tonight. Cannot rule out a few gusts up towards Small Craft Advisory criteria late this evening, but it's not consistent enough to warrant an issuance. Seas get nudged up towards 2-4 ft at this time. Gradient starts to gradually come down heading towards sunrise Wednesday morning, with winds veering to the NNE after the front passes. Seas gradually come back down towards 1-2 ft throughout the day. Winds then go back towards the SW later in the afternoon ahead of yet another weak front.

Wednesday Night through Sunday...Another frontal passage will lead to an increase in winds Wednesday night, just below SCA thresholds for now. Calmer winds in place through Monday until an approaching offshore low brings gale force gusts and winter weather this weekend. Seas 2-4 ft with the frontal passage becoming largely 2 ft through Monday before a large increase into the weekend just like the winds. Highest waveheights should be Saturday night into Monday at 4-7 ft, 9 footers possible ~20 nm off Cape Fear.

ILM WATCHES/WARNINGS/ADVISORIES

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