textproduct: NWS Wilmington

WHAT HAS CHANGED

Today's forecast highs have been lowered further by blending in 06z HRRR and 06z NAMnest. Highs should remain in the mid 30s for Elizabethtown through Wilmington, and generally upper 30s to near 40 elsewhere.

KEY MESSAGES

1) Rain will taper off to drizzle this morning, but not before freezing temperatures arrive across inland portions of southeastern North Carolina. Minor ice accumulations are possible on elevated objects from Lumberton to Burgaw.

2) An Arctic cold front will bring a very cold weekend. A Cold Weather Advisory may be needed Saturday night.

DISCUSSION

KEY MESSAGE 1: Rain will taper off to drizzle this morning, but not before freezing temperatures arrive across inland portions of southeastern North Carolina. Minor ice accumulations are possible on elevated objects from Lumberton to Burgaw.

Shallow low level cold air will sink south behind a cold front this morning. Rain and areas of drizzle associated with weakening isentropic lift over the front should coexist with freezing temperatures for several hours across Lumberton, Elizabethtown, and Burgaw where a trace or perhaps a couple hundredths of an inch of ice could accumulate on elevated objects. Yesterday's relatively warm temperatures in the 50s and the short period of time air temps will be below freezing this morning should preclude any icing issues on surface roads, but bridges, outdoor stairs, and decks could pick up a glaze of ice.

Forecast highs today have been lowered by a few degrees in deference to the wedge-like cold advection pattern with dense clouds above. This idea is further validated by high-res guidance (HRRR and NAMnest) that performed relatively well during the January 25 ice event. Across the Winter Weather Advisory area temperatures should rise above freezing around noon, but should remain stuck in the chilly 30s everywhere beneath a dense overcast for most of the day. Clearing may begin to arrive late in the afternoon along and west of I-95.

There is some uncertainty regarding how quickly low clouds break along the coast tonight. The NAM in particular wants to hold onto more cloud cover than the GFS with possible implications for overnight temperatures. NBM blends look reasonable given the uncertainty and range from the low-mid 20s across SE North Carolina to the mid-upper 20s across NE South Carolina. Some fog can't be ruled out given there's nothing obvious to scour out today's low level moisture.

KEY MESSAGE 2...An Arctic cold front will bring a very cold weekend. A Cold Weather Advisory may be needed Saturday night.

Though the initial Arctic FROPA is Friday there is a secondary push of even colder air on Saturday where 850mb temperatures fall to -10C over northern zones before slight recovery gets underway. This paves the way for a 1032mb high to plunge into the Eastern U.S. over the weekend. Both Saturday and Sunday will feature highs that are in excess of 10 degrees shy of climatology. In between is where some hazards may come into play. As Saturday night lows drop into the low 20s/upper teens wind chill values could reach advisory-worthy values of 15 or less especially over northernmost zones.

AVIATION /12Z THURSDAY THROUGH MONDAY/

IFR conditions are in place for all local airports except KLBT. Observations across a good deal of central North Carolina show ceilings have risen to MVFR or even VFR. Model trends are beginning to shift toward a faster breakup of the low IFR ceilings today and our new 12z TAFs reflect this trend. IFR conditions are expected to end by 15z at KILM and KFLO, and by 18z at KCRE and KMYR. It still may take until this evening for MVFR ceilings to fragment.

The other item of concern is below-freezing surface air temperatures are sinking southward and have changed precipitation over to freezing drizzle or light freezing rain at KLBT. This FZDZ/FZRA may continue through 15z before ending. Temperatures will fall very close to the freezing point between 12-15z at both KFLO and KILM but the probability of freezing precipitation appears too low to mention in the TAF.

Otherwise breezy northerly winds could gust to 20 knots at times today.

Extended Forecast...There remains a moderate risk of ground fog or low ceilings developing after 06z tonight at KFLO and KLBT lasting into Friday morning. VFR conditions should then prevail through Monday.

MARINE

Through Tonight...A cold front located near Cape Fear at 1 AM should push south and past Georgetown and Winyah Bay by sunrise. Breezy north winds behind the front could gust as high as 25 knots for the waters near and east of Cape Fear. The strongest winds are anticipated this afternoon through early this evening. A Small Craft Advisory will remain in effect for the North Carolina coastal waters, but has been dropped across South Carolina where it appears wind speeds will top out near 20 knots.

Low pressure will deepen offshore along the front tonight and push northeastward away from the Carolinas. High pressure centered across the Gulf will ridge eastward with lighter wind speeds expected to develop after 2-3 AM Friday morning.

Friday through Monday night... An Arctic cold front on Friday will bring a surge of advisory-worthy winds by nighttime. A secondary push of cold air Saturday will keep headlines in full effect. Previous wave guidance was keeping 6 ft seas outside of the 20nm zones in the offshore fetch though now they are depicted along Frying Pan Shoals. The shorter period wind wave will dominate in the agitated post-frontal flow whereas a bit of an easterly swell will mix in with the wind chop by Sunday/Monday as wind fields collapse to nearly light and variable.

ILM WATCHES/WARNINGS/ADVISORIES

NC...Winter Weather Advisory until 11 AM EST this morning for NCZ087-096-105. SC...None. MARINE...Small Craft Advisory until 9 PM EST this evening for AMZ250- 252.