textproduct: Raleigh

WHAT HAS CHANGED

As of 200 AM Sunday...

Snowfall slowly coming to an end into early Sunday.

A fast moving system will bring a chance of precipitation Tuesday night through Wednesday night, falling mostly as rain, though a few snowflakes could mix in late Wednesday night.

KEY MESSAGES

As of 200 AM Sunday...

1) Bitter Cold temperatures today under fresh snow cover. Black ice will be a threat tonight

2) Well below normal temperatures will persist through next weekend as Arctic air remains in place across the region.

3) A fast moving system will bring a chance of precip to the area Tuesday night through Wednesday night. Precip should be light, fall mostly as rain, although a few snowflakes could mix in late Wednesday night.

DISCUSSION

As of 200 AM Sunday...

KEY MESSAGE 1... Bitter Cold temperatures today under fresh snow cover. Black ice will be a threat tonight

Latest satellite imagery reveals the deep and vigorous upper-level trough off the SC coast. The system will continue to track ENE into daybreak Sun morning. As it does so, the system will start to shear out, which will lead to the deep lift and 850-700 mb FGEN to weaken with time. Radar returns combined with webcams showed the northern Piedmont and northern Coastal Plain starting to clear out in terms of snow, with just isolated reports of lingering light snow. Light to moderate snow was persistent south of US-64 and especially over the Sandhills and into the Central Coastal Plain along I-95.

Snow should taper off by sunrise, but a few lingering light snow or flurries may exist over southern Sampson until 8 am. As a result, the Winter Storm Warning will likely be allowed to expire by 7 am for most, if not all, of central NC.

Bitter cold temperatures and dangerous wind chills will persist even after the snow has ended. The Extreme Cold Warning persists until 10 AM, where wind chills into mid-morning will range from zero to 5 below with NW winds in the 20 to 30 mph range and temps in the low/mid teens. Skies should clear out today with plentiful sunshine. But fresh snow cover will limit our highs. We undercut highs, despite NW downslope winds of 20 to 30 mph, in the mid 20s to near 30 degrees. Wind chills this afternoon will hover in the teens. Tonight, weak ridging at mid-levels spreads east from the TN valley and that should favor winds going light or calm overnight into Mon morning. With a fresh blanket of snow, excellent radiational cooling suggests lows in the single digits to low teens, in line with the colder EC MOS guidance. A Cold Weather Advisory may be needed tonight with wind chills in the single digits to near zero. Although there won't be much melting today, the sun will help somewhat. Refreezing of slush will warrant the threat of black ice across central NC. A Winter Weather Advisory or SPS may be issued later today as a result.

KEY MESSAGE 2... Well below normal temperatures will persist through next weekend as Arctic air remains in place across the region.

In the wake of the coastal low, surface high pressure will settle over the area Monday into Tuesday. While winds will turn out of the south and temperatures will moderate slightly into the low/mid 40s, these readings will remain well below normal for early February. Temperatures will retreat into the 40s and upper 30s by the middle of the week as a weak wave passes through the area, then rebound slightly into the mid/upper 40s to close out the week. Overnight lows this week will also remain well below normal with teens and 20s to start the week, mid 30s on Wednesday, then back into the teens and 20s Thursday and Friday.

KEY MESSAGE 3... A fast moving system will bring a chance of precip to the area Tuesday night through Wednesday night. Precip should be light, fall mostly as rain, although a few snowflakes could mix in late Wednesday night.

Once again, there is good ensemble agreement on a fast moving shortwave trough digging through the area late Tuesday night/Wednesday morning, exiting the area late Wednesday night/Thursday morning. Timing among the GFS/GEFS/EC/ECENS is much more consistent with today's 12Z suite of guidance showing precip moving in from west to east late Tuesday night. Weak WAA ahead of the trough could result in some snowflakes mixed in at precip onset, but this should quickly turn to rain as the boundary layer rises above freezing. Precip continuing at times through the day although ensemble mean QPF is only a few hundredths of an inch. Even the 90th percentile QPF is less than a quarter of an inch based on this morning's guidance. As the trough moves off the coast and post- frontal cold advection takes hold, the entire thermal profile should slip below freezing. There could be a few snowflakes that mix in as precip is exiting the area but dry air chasing the precip would suggest a limited threat of snow accumulation.

AVIATION /11Z SUNDAY THROUGH THURSDAY/

As of 605 AM Sunday...

24 hour TAF period: Widespread snow across central NC on Saturday and Saturday night has exited just about all of central NC. There are now no METARs from central NC that are reporting snow as of 6am. While the precipitation is over, there could be a brief restriction at a few sites down to 5SM in blowing snow through mid morning. VFR conditions are now noted across all of central NC an will continue through the remainder of the TAF period. Gusty winds will continue through the morning into the afternoon before the gusts subside during the mid to late afternoon. Sustained winds will relax tonight although the boundary layer is likely to remain mixed or much of the overnight.

Outlook: VFR conditions and fair weather is expected through Tuesday. The next weather system will bring a chance of sub-VFR conditions and precipitation Tuesday night through Wednesday night. Fair weather should return for Thursday.

CLIMATE

Record Low Temperatures:

February 1: KGSO:-4/1936, KRDU: 8/1981, KFAY: 1/1936

Record Low Maximum Temperatures:

February 1: KGSO: 27/1971, KRDU: 28/1900, KFAY: 32/1981 February 2: KGSO: 30/1951, KRDU: 31/1994, KFAY: 31/1948

RAH WATCHES/WARNINGS/ADVISORIES

Extreme Cold Warning until 10 AM EST this morning for NCZ007>011-021>028-038>043-073>078-083>086-088-089.