textproduct: Newport/Morehead City

WHAT HAS CHANGED

Winter Storm Watch continues for the coastal plain from Saturday afternoon into Sunday afternoon.

KEY MESSAGES

1) An Arctic front will push through the area tonight with a low pressure system passing through ENC this weekend, bringing a wintry mix of some snow, but mostly sleet and freezing rain to ENC, especially inland areas. Winter Storm Watch remains in effect for the western counties of the Coastal Plain of ENC.

2) Cold airmass builds in behind the system through much of next week with below normal temperatures with highs in the 30-40 degree range and lows 15-25. Winds chill may fall below 15 degrees a few mornings, coldest likely Tue morning.

DISCUSSION

KEY MESSAGE 1... An arctic cold front will push through the area tonight, with scattered areas of light rain ahead of it during the day. Temps will be in the 50s and precip will be all liquid. Arctic high pressure builds into the area from the north tonight behind the front and sets the stage for overrunning wintry mix on Sat as isentropic ascent increases and wet bulbing keeps surface temps only in the 30 degree range or so throughout the day for much of the region. Cold apparent temperatures will be in place tonight into Saturday morning with values below 15 degrees possible for northern and western counties. Will cold off on Cold Weather Advisory for now. Mix of light snow and sleet will likely break out across ENC late Saturday morning but increasing into the afternoon and evening hours as isentropic ascent increases. Limited accums expected during the day as QPF amounts will be quite light, amounting to only several hundredths of an inch. However, with cold air and ground temps, some slick spots will likely begin to develop on some of the elevated surfaces away from the coast where temps hover around in the upper 20s to lower 30s much of the day. By Saturday night, low pressure will develop along stalled front, coastal trough offshore and begin to more northeastward and penetrate into Eastern NC through the overnight. The big change with this forecast is Sat night into Sun. This brings substantial warming aloft, with 850mb temps fcst to reach between 5-10C by daybreak Sunday, while stubborn CAD remains at the sfc west of Hwy 17. Little change in 00z model guidance, which brings sfc warming above freezing from E to W across ENC through the overnight, limiting duration of icing for areas along and east of Hwy 17. West of Hwy 17, the CAD holds strong through Sunday morning, leading to more prolonged QPF at below freezing temps. At this time fzra amounts look to be in the .20"-.30" range, with locally higher amounts up to around 0.50" for far western communities possible. CAD still expected to erode further inland and temps rise above freezing Sunday afternoon, and the warm sector dry slot will overspread ENC as the low moves through the area.

Regarding winds with arctic front tonight and Sat morning, it appears the surge will be brief enough and a bit more marginal for wind adv headlines on the OBX attm. Water level rises may rise a bit above normal for southern areas of Pamlico Sound, but brief surge should limit any impacts.

KEY MESSAGE 2...

Arctic high pressure will build in behind the departing system through much of next week. Temperatures will be quite a bit below normal, with highs in the 35-45 degree range, and lows in the 15-25 degree range. Wind chill values will possibly dip down through the teens each night and morning beginning Monday night through much of next week. A reinforcing cold front will move through mid week, as cold air persists across the area.

AVIATION /12Z FRIDAY THROUGH TUESDAY/

VFR flight cats are expected through the TAF period. Scattered light showers in the area continue this morning, though most of radar returns don't have precip reaching the ground, hence limiting precip mention to VCSH. Bring back VCSH mention this evening as light rain associated with FROPA. Generally light Nerly winds through the day until after midnight local when Nerly winds pick up behind the front, 10G15-20kt. Lower CIGs in MVFR range expected overnight across OBX.

Outlook: An extended period of sub-VFR conditions is possible this weekend as a significant winter storm impacts the area. All winter precip types are possible through the weekend, although it looks like a mix of rain/freezing rain will be the dominant P-Types. KISO and KPGV are expected to receive the greatest impacts due to ice accumulation but ice will be possible at all terminals. Cold high pressure early next week means quiet VFR flight cats.

MARINE

Latest obs show W-N winds with seas 2-4 ft. Light to moderate N-NE winds will continue today. An arctic front will push through tonight with strong northerly winds developing and seas quickly building to 6-9 ft. Gale Warnings and SCAs continue, with winds slowly diminishing from north to south through the day Sat.

Saturday night through Tuesday: Winds become E-SE Sat night then swrly on Sunday as low pressure tracks just inland from the coast. SCA conditions likely for the warmer and well mixed gulf stream waters, with sub 20 kt winds elsewhere. SCA conditions will continue into early next week with lingering elevated seas and gusty winds. Another brief period of gale force winds will be possible Monday night. Winds and seas will gradually ease through the day Tuesday.

MHX WATCHES/WARNINGS/ADVISORIES

NC...Winter Storm Watch from Saturday afternoon through Sunday afternoon for NCZ029-044-079-090-091. MARINE...Small Craft Advisory from 1 AM Saturday to 1 AM EST Sunday for AMZ131-136-137-230-231. Gale Warning from 1 AM to 1 PM EST Saturday for AMZ135-152-154. Gale Warning from 1 AM to 10 AM EST Saturday for AMZ150. Gale Warning from 3 AM to 7 PM EST Saturday for AMZ156-158.