Key message 1,
BLUF, We're still tracking the potential for a changeover to snow late this afternoon for portions of the NC coastal plain. For most this changeover will be non-impactful with temperatures above freezing and snow rates fairly light. However, there is potential (though small ~30%) for portions of Martin, Pitt, and Washington counties to see minor snow accumulations after this changeover IF temperatures fall quickly to around freezing AND snow rates are moderate to high. In a reasonable worst case scenario (10% probability), some minor travel impacts could occur due to a coating of snow on roadways/pavement. The likelihood of this scenario is too low to issue a Winter Weather Advisory, but hope that this discussion on other messaging raises awareness to this low probability but potentially impactful event.
A cold front will push offshore later this morning and then an area of low pressure will move along it this afternoon/evening off the NC coast. Rain (already overspreading the area) will continue through the day, and CAA behind the front will cause temps to drop through the day. By this afternoon, temps will drop into the 30s over the northern coastal plain, and snow may begin to mix in with rain. After this point is where the crux of the uncertainty lies. Even at this close time range, it's uncertain how quickly temps will fall late this afternoon and there remains a fairly even split between warmer guidance (rain), and cooler guidance (snow). If rain does change to snow fairly quickly, surface temperatures will still be above freezing, keeping any snow accumulations to elevated surfaces. However, across the NW coastal plain temperatures may fall close enough to freezing for some minor accumulations to occur on the ground, and if snow rates are high enough, some minor travel impacts could occur due to a coating of snow on roadways/pavement. Rain/snow will taper off fairly quickly this evening, but a brief changeover to snow is possible all the way east to the NOBX.
key message 2,
There remains some potential for the development of black ice overnight into the Mon AM commute time if heavier rainfall totals are seen and leave wet roads and bridges, as temps will crash hard into the 20s overnight. First ones to ice up will be bridges and overpasses.
Key MESSAGE 3,
Another Arctic blast is expected behind the front, leading to well below normal temps Monday through Wednesday. Low temps will reach the low 20s, and when factoring in wind chills it will feel like the teens each morning. We will be close to Cold Weather Advisory criteria both Tuesday morning (wind chills), and Wednesday morning (air temps). Wed morning is the coldest with high pressure directly overhead with lows in the teens areas away from the immediate coast.
12z Sunday through Thursday VFR conditions are currently noted across just about all of ENC. However, conditions are still forecast to rapidly deteriorate over the next few hours as rain continues to overspread the area. While rain will likely persist through most of the day could see a brief changeover to snow around 20-21Z for our terminals west of Hwy 17 but minimal impact is expected even if this does occur.
Made some slight tweaks to the forecast as MVFR ceilings have been slow to develop this morning. Either way, still expect MVFR ceilings to develop across all of ENC between 13-15Z now. In addition to this, ongoing rain should continue to increase in coverage and intensity this morning. As this occurs, also expect ceilings to continue to lower to IFR levels between 15-17Z. Vis also likely drops to around 3-4 sm after sunrise Sun and linger at those levels through 00z, although more localized severe drops are possible in heavier rain. After 21z, colder post-frontal air will catch up to deeper moisture and will likely see a mix of rain and snow for terminals west of Highway 17. This changeover will not last long, and given expected rainfall prior and warm surface temps little to no accum is forecast. Winds will be 5-10 kt out of the NW through the afternoon. As we get into tonight, any leftover rain and snow quickly push offshore between 0-3Z and skies quickly clear behind the departing low and associated fronts. This however then leads to the next forecast challenge which is the potential for fog overnight Sun. Winds ease and skies will be clear while dry air works its way into ENC. Given todays rainfall the low levels will likely be saturated so this would be a good setup for fog development overnight. However, guidance has begun to back off potential development so have kept any fog threat out of the forecast for now.
Outlook: Outside of the fog threat expect primarily VFR conditions across ENC from Mon morning and beyond. While no snow accumulations are expected, there's concern for black ice Sunday night/Monday morning. Some freezing fog may also be possible Mon morning especially for OAJ and potentially EWN. Dry high pressure returns Monday, bringing a return to VFR conditions across all of ENC through mid week.
A brief spell of calmer conditions will end later this morning as winds pick up behind a cold front. Small Craft conditions are expected to develop across the coastal waters and eastern sounds this afternoon through most of tonight as winds become NW 20-30 kts with a few gusts to 35 kts, and seas 4-7 ft.
Conditions will temporarily improve tomorrow morning with winds W 10-20 kts, and seas 3-5 ft, but winds will again increase tomorrow night to WNW 15-25 kts with Small Craft conditions possibly redeveloping across portions of the coastal waters.
Outlook: Lighter winds expected Tuesday at NW 10-20 kts, with winds becoming southerly at 5-15 kts Wednesday. Another Arctic front will move through Thursday with Small Craft conditions possible into Friday.
Nc, none. Marine, small craft advisory from 3 pm this afternoon to 1 am EST Monday for amz135. Small craft advisory from 1 pm this afternoon to 4 am EST Monday for amz150-156-158. Small craft advisory from 1 pm this afternoon to 6 am EST Monday for amz152-154. Small craft advisory from 3 pm this afternoon to 11 pm EST this evening for amz231.
