textproduct: NWS Wilmington

WHAT HAS CHANGED

A Winter Weather Advisory has been issued for the potential of a trace amount of ice late tonight and early Thursday. No significant winter weather impacts are expected.

KEY MESSAGES

1) Light rain is expected today and tonight, ending as non-impactful period of light freezing rain late tonight and Thursday morning.

2) Another period of cold weather is expected behind an arctic cold front Friday night.

DISCUSSION

KEY MESSAGE 1: Light rain is expected today and tonight, ending as non-impactful period of light freezing rain late tonight and Thursday morning.

No significant winter weather impacts are expected tonight and early Thursday.

Warm air advection has pushed temperatures a full 10-15 degrees warmer since sunset and much of the area has settled into the mid and upper 40s. Within this comparatively warmer air mass, moisture and isentropic lift have increased along all significant theta levels. As deep-layer moisture pushes eastward into the region today, this should set the stage for widespread liquid rain.

The best isentropic upglide remains west of the region as of the 1 AM AFD window, but a sinking cold front from southern VA and increasing moisture advection out of the SW will push that corridor of lift and rain eastward into the afternoon. Intermittent light rain is expected for much of the day for inland areas. This is corroborated by current radar imagery to our west. However, the slow progression of both features will likely cause coastal areas to stay dry until the afternoon. Lift will deepen this evening as trough deepens over the lower Mississippi River Valley and low level CAA pushes farther southward. A period of heavier rain will be possible during this window of enhanced lift.

The extended residence of moisture should produce a respectable amount of QPF with rainfall totals up to an inch along and just east of I-95.

Cold air behind the front will bring temperatures near freezing across the northern tier of our area tonight and early Thursday. Some light freezing rain is possible as this occurs. Soundings at LBT, EYF, and ACZ identify the strong warm nose late tonight and maintain its strength due to the limited depth of near-surface CAA. This implies that no other p-type (other than liquid rain) is possible. Moisture will be increasingly shallow after 06Z tonight, so precip rates will already be hindered by the depth of saturation.

Intermittent freezing drizzle will be possible for a brief period between 08Z-14Z. HREF guidance hints that moisture may become entirely insufficient for precip as early as sunrise. Shortly after sunrise, temperatures near freezing and weak CAA will then fight diurnal forces below a progressively thinning cloud layer. A trace to a couple of hundreths of ice are possible. This is unlikely to cause any significant impacts, especially as our road temperatures have recovered slightly over the past couple of days. However, caution would suggest to watch for potential slick spots on bridges and overpasses. A Winter Weather Advisory has been issued due to the trace of expected ice, but, again, significant impacts are not anticipated.

KEY MESSAGE 2: Another period of cold weather is expected behind an arctic cold front Friday night.

A series of shortwaves will move across the Great Lakes and out over the western Atlantic late this week, carving out another deep and cold trough. An arctic cold front will push through the eastern Carolinas Friday night and will be followed by well-below normal temperatures through the weekend.

Of particular concern are forecast low temperatures Saturday night which could reach near 20 degrees inland. Enough wind may linger to push wind chills toward the critical 15 degree threshold for a Cold Weather Advisory, particularly across the coastal counties in the Cape Fear region. Given the deep layer of northwesterly winds crossing the Appalachians, forecast precip chances are near zero through the weekend.

And lastly, a climate note: the 13 day period Jan 27 through Feb 8 may turn out to be the coldest such period in Wilmington since the arctic chill of early January 2018. Using observed data at Wilmington plus our forecast highs and lows out through Sunday, the calculated 13-day average temperature of 33.6 degrees F would fall in 20th place behind January 2018, January 2010, January 2001, December 1989, and other historic arctic outbreaks.

AVIATION /06Z WEDNESDAY THROUGH SUNDAY/

VFR conditions are expected for the next 6 hours or so. Increasing moisture and lift will bring precip during the mid morning inland and early afternoon at the coast. In a warm advective regime, confidence is slightly lower in seeing IFR CIGs through the afternoon. However, tonight and especially as a cold front pushes through the area, CIGs will approach airport minimums. Light to moderate rain will solidify IFR and MVFR VIS today. Winds remain light but will be variable between SW early today and N tonight. Some light freezing rain is possible at LBT late tonight and early Thursday.

Extended Forecast... Widespread IFR improves by late Thursday morning. VFR thereafter.

MARINE

Through Tonight... Light and variable winds are expected today as a cold front slowly drifts southward through early Thursday. Winds increase rapidly on Thursday as high pressure builds across the region.

Thursday through Sunday Night...Small Craft Advisory conditions may occur Thursday and again Friday night into Saturday. A surge of north-northeasterly winds building down the coast behind Thursday morning's cold front could reach 20-25 knots for locations near and north of Cape Fear. The period of strongest winds should center on Thursday afternoon into Thursday evening before diminishing overnight as low pressure along the front zips farther out to sea.

A second period of Small Craft Advisory conditions may develop Friday night as a dry arctic cold front pushes through from the northwest. Systems like these are sometimes called "Clippers" and this one will be followed by 24 hours of cold gusty north winds and seas in the 3-6 ft range.

ILM WATCHES/WARNINGS/ADVISORIES

NC...Winter Weather Advisory from 4 AM to 11 AM EST Thursday for NCZ087-096-105. SC...None. MARINE...None.