textproduct: NWS Wilmington

WHAT HAS CHANGED

Still expecting some additional ice accumulations along the I-95 corridor this evening due to a line of showers and mixed precip. Temperatures are generally below freezing, but pockets of heavier precip are bringing slightly warmer temperatures into the shallow cold air. Additionally, rainfall rates should be too high for all of this rainfall to exist as freezing rain, with a large portion of the precip previously being reported as mixed sleet and freezing rain. Erosion of the shallow cold air following the line should push temperatures above freezing tonight.

KEY MESSAGES

- 1) Lingering cold air damming will maintain a risk for freezing rain, drizzle, and fog into tonight for inland areas with a gradual warming trend ending the ice threat from southeast to northwest.

- 2)An extended period of very cold weather is expected all week and into the weekend. Nighttime apparent temperatures could necessitate a Cold Weather Advisory for at least part of the area Monday and Thursday night as well as Friday and Saturday night.

DISCUSSION

KEY MESSAGE 1: Lingering cold air damming will maintain a risk for freezing rain, drizzle, and fog into tonight for inland areas with a gradual warming trend ending the ice threat from southeast to northwest.

KEY MESSAGE 1 DESCRIPTION... While precipitation has mostly ended across the forecast area, lingering cold temperatures and a thinning cold wedge with strong south to southwest winds riding over it are supporting continued freezing drizzle, mist, and fog across the area away from the coast. Occasional freezing rain showers will remain possible across inland areas until a band of rain arrives from the west ahead of a cold front. Given this dense, cold airmass has been keeping temperatures colder for longer than anticipated, it is becoming increasingly likely that far northwest portions of the forecast area will not rise above freezing by the time this band of rain comes in. Thus, growing confidence exists for another round of accumulating ice in portions of Darlington, Marlboro, Dillon, and Robeson counties where temps stay below freezing through this evening. An additional tenth to two tenths of an inch of freezing rain is possible, mainly in Darlington and Marlboro county, with lesser amounts in Robeson and Dillon county.

The incoming band of rain will occur within, and will be preceded by, a surge of south to southwesterly winds aloft, and this will be the last ditch effort to erode away the cold wedge from the top down. Whether this occurs is still in question, and thus, temperatures across the area carry lower confidence due to the stubborn nature of the cold wedge. Nevertheless, temperatures should at least warm into the 40s in the coastal counties this evening, with low to mid-50s possible along the immediate coast if the cold wedge can erode away entirely. This band of rain may also bring occasional rumbles of thunder as weak elevated instability arrives. Additional rainfall of around 0.50" is expected, with higher amounts possible along the coast where rain will linger through most of tonight. Relatively warm, moist air within and behind the rainfall band will keep a risk for mist or fog in place through the rest of tonight, before breezy west winds bring in colder and drier air on Monday.

KEY MESSAGE 2...An extended period of very cold weather is expected all week and into the weekend. Nighttime apparent temperatures could necessitate a Cold Weather Advisory for at least part of the area Monday and Thursday night as well as Friday and Saturday night.

KEY MESSAGE 2 DESCRIPTION... Arctic air will be pouring into the region Monday night. Temperatures at 850mb bottom out at -10C, supportive of lows in the mid to upper teens. A few knots of northerly winds will push apparent temperatures below the Cold Weather Advisory-worthy values of 15F across all but perhaps our southernmost zones. After a very paltry recovery Wed and Wed night the next Arctic boundary arrives Thursday and another one Saturday, the latter accompanied by dynamics aloft. This system in previous guidance has been hinting at wintry accumulations in the Southeast but it now appears that the cold air will be so deeply entrenched that accumulating snow could very well remain suppressed to our south and offshore, a rarity indeed.

AVIATION /00Z MONDAY THROUGH FRIDAY/

Patchy fog (some areas with temperatures still below freezing) and precipitation will limit VIS and CIGs this evening. A line of sleet, freezing rain, heavy rain, and isolated thunderstorms will move through the region over the next few hours. Once the line reaches the coast, rain will likely linger through the overnight hours as the trough stalls. Prolonged IFR near airport minimums should linger through sunrise. LLWS will continue as the low level jet moves offshore with the front after midnight. By midday, inland sites should see VFR return with the coast potentially not seeing cigs scatter out until afternoon. Breezy NW winds early in the day should weaken by late afternoon.

Extended Forecast... VFR.

MARINE

Through Monday... Northwest winds will continue to weaken and back this afternoon, with south to southwesterly winds ramping up this evening into the 20-25 kt range as the cold wedge is eroded away over the waters ahead of a cold front. A band of rain and isolated thunder will shift over the waters ahead of the front and winds will turn westerly by late tonight as the cold front shifts through and brings an end to the rain. Winds back to northwesterly on Monday and continue at around 20 kts with gusts around 25 kts through the day. Seas will peak around 4-7 ft tonight amidst breezy southwest flow, before very gradually subsiding through Monday.

Monday night through Friday...With the series of Arctic boundaries pushing across the waters wind will not get much a chance of deviating from N to NW through the period and wind speeds will never get a chance to settle much though actual advisory conditions will be hard-pressed to develop as the largest waves remain outside of the 20nm forecast zones. Swell energy similarly remains well out to sea in the offshore fetch leaving the wind chop the dominant wave through the period.

ILM WATCHES/WARNINGS/ADVISORIES

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