textproduct: NWS Wilmington

WHAT HAS CHANGED

00Z Aviation discussion has been updated.

No significant changes regarding winter weather tonight through Sunday.

KEY MESSAGES

1) Freezing rain will be a primary hazard associated with this winter storm through Sunday, bringing the potential for downed trees and power outages, especially around and west of the I-95 corridor.

2) Below normal temperatures will continue through the week with dangerously low wind chill temperatures at times, especially Monday and Thursday nights.

DISCUSSION

KEY MESSAGE 1: Freezing rain will be a primary hazard associated with this winter storm through Sunday, bringing the potential for downed trees and power outages, especially around and west of the I- 95 corridor.

Cold and very dry air has seeped southward today on north to northeast winds. This shallow cold air mass is approximately 2000 ft thick as per model soundings and will gradually get thinner and thinner with time. Isentropic upglide will ramp up this evening as south to southeast winds bring in plentiful moisture and lift it along the 285-295K surfaces over the cold air mass. This will bring increasing chances for precipitation overnight, and with stratiform precip being generated where air temps will be as high as the 40s to low-50s, it will most likely stay as a liquid to the ground. The biggest questions are the coverage of precip and how long it takes the initial rain falling into the dry air mass to moisten it up and reach the ground. This will have an impact on the duration of ice accretion and potential impacts. Ultimately, precip chances will continue through tomorrow morning before isentropic lift weakens and the overall coverage decreases, although spotty light freezing rain will remain possible west of I-95 through midday before temps warm up enough to end the freezing rain threat, except in locally colder spots.

During Sunday afternoon and evening, strong south to southwest winds above the cold wedge will be trying to erode away at it from the top down, causing it to thin until it is no more. Near the coast, this appears more likely to occur while inland areas have a lesser chance of seeing this. If this does indeed occur, a rapid warm up into the 50s and sudden increase in south to southwest winds will be observed either late tomorrow afternoon or during the evening ahead of a cold front. This front will bring a band of moderate to heavy showers and possibly some embedded thunder for the overnight hours Sunday night into early Monday.

KEY MESSAGE 2: Below normal temperatures will continue through the week with dangerously low wind chill temperatures at times, especially Monday and Thursday nights.

Well below normal temperatures are expected to continue through the week as a few cold fronts pass through the area with several nights in the teens, especially inland. Cold Weather Advisories are a very good bet at least Monday and Thursday nights with the potential for an Extreme Cold Warning Thu night for wind chills of 5 degrees or less, mainly across northern areas toward the NC Sandhills.

AVIATION /00Z SUNDAY THROUGH THURSDAY/

Deepening isentropic lift will force conditions to deteriorate on schedule this evening. Freezing rain is likely to impact all inland terminals overnight. There could be a brief period of freezing drizzle at the coastal terminals, but impacts are not expected. MVFR CIGs will gradually become IFR overnight. Inland terminals will see conditions worsen first with coastal terminals to follow shortly after. IFR will continue through Sunday as a strong inversion maintains shallow cold air. This inversion will become so shallow that LIFR or lower CIGs will be possible late tonight into Sunday. Improvement is not likely until the afternoon when the wedge starts to erode. Gusts may increase substantially late in the day as the cold wedge begins to erode, but confidence is low at this time. Regardless of gusts at the surface, a strong low level jet will likely exist after mid morning, producing prolonged LLWS through Sunday evening.

Extended Forecast...The winter storm will continue impacting the are through Monday morning, with flight restrictions expected until moisture is scoured out behind a cold front on Monday. VFR should return by Monday afternoon and prevail through the remainder of the period.

MARINE

Through Sunday... Breezy northeast winds of 20-25 kts will continue into tonight before slackening after low pressure passes by just off the coast late in the night. Winds turn northwesterly behind the low during the morning and weaken to around 10 kts. Winds will continue backing as the low-level cold wedge is eroded away. Eventually, southwest or south winds will become dominant ahead of a cold front, although this may hold off until Sunday evening. Seas peak this evening in the 5-9 ft range before gradually subsiding as the winds come down, although the Small Craft Advisory will continue through the period as seas remain at or above the 6 ft threshold.

Sunday night through Wednesday night...A Small Craft Advisory will continue through Monday night for hazardous winds up to around 30 kt and seas up to near 9 ft until high pressure builds in bringing a weaker pressure gradient at least temporarily. Another cold front should move through Tuesday night bringing another surge close to Advisory levels. Similar situation again on Wed/Wed night with another cold frontal passage.

ILM WATCHES/WARNINGS/ADVISORIES

NC...Ice Storm Warning until 1 AM EST Monday for NCZ087. Winter Weather Advisory until 7 PM EST Sunday for NCZ096-099- 105>110. SC...Ice Storm Warning until 1 AM EST Monday for SCZ017-023-024. Winter Weather Advisory until 7 PM EST Sunday for SCZ032-033- 039-054-055-058-059. MARINE...Small Craft Advisory until 7 AM EST Tuesday for AMZ250-252-254- 256.