textproduct: NWS Wilmington

WHAT HAS CHANGED

Aviation discussion updated for the 12Z TAFs.

KEY MESSAGES

1) Elevated fire danger today.

2) Hazardous marine conditions into Sunday.

3) Freezing temperatures are possible inland tonight, especially across the NC Coastal Plain away from the coast west toward the SC Pee Dee.

4) Unsettled weather is possible during the latter half of next week, but confidence is low regarding the details.

DISCUSSION

KEY MESSAGE 1...Elevated fire danger today.

Dry and breezy conditions are expected today behind a passing strong cold front. These meteorological conditions along with dry fine fuel conditions from the ongoing drought will lead to an increased fire danger. A Red Flag Warning will be in effect for northeast SC and a Fire Danger Statement will be in effect for southeast NC after coordination with state/federal fire partners. There is still a chance that the Fire Danger Statement in NC will be upgraded to a Red Flag Warning later this morning after additional examination of the forecast and coordination with fire partners.

KEY MESSAGE 2...Hazardous marine conditions into Sunday.

See the Marine section below for details.

KEY MESSAGE 3: Freezing temperatures are possible inland tonight, especially across the NC Coastal Plain away from the coast west toward the SC Pee Dee.

Surface high pressure will build in from the north tonight leading to fairly light winds and with little to no clouds, conditions should be pretty good for radiational cooling, especially inland (mainly near/west of I-95). Thus, we leaned toward the colder model guidance which means there is a decent risk for temperatures to fall to at least 32 degrees. There remains some uncertainty regarding how quickly, how much and where decoupling occurs as this will impact winds, and thus temps as well. Frost will also be possible away from the immediate coast and a Frost Advisory could eventually be needed for a portion of the area outside of any potential Freeze Warning areas. Those with concerns about sensitive vegetation should monitor the forecast and take proper precautions.

KEY MESSAGE 4... Unsettled weather is possible during the latter half of next week, but confidence is low regarding the details.

A complicated upper pattern evolution is expected to take place next week. First, an upper trough and associated surface low crossing the northern US during the early to middle part of the week is expected to leave a stalled front extending from the Lower Mississippi Valley into the Mid-Atlantic. With robust surface high pressure stationed near Bermuda, expect gradually warming temps and rising dew points through midweek. Next, a powerful trough is expected to enter the Pacific Northwest on Wednesday night or Thursday while a southern stream shortwave trough and ridge pair cross the country ahead of it. The details pertaining to how the Pacific Northwest trough evolves, and subsequently how the downstream pattern responds, results in low confidence for how unsettled the weather will become as the placement of the stalled front will be affected by these upper features. Furthermore, a strong high pressure center translating across southern Canada on the north side of the stalled front will also influence how far south the front settles.

Run-to-run consistency amongst operational model guidance has been low over the last several runs and cluster analysis tools generally support a drier scenario being the most likely outcome with the wetter scenario being the next most likely. Thus, while it appears the stalled front and its higher precip amounts should stay northwest of the area, daily chances for pop-up showers and thunderstorms may ensue from Wednesday onward as the warm and humid Bermuda high pressure pattern supports a more summer-like result. Nevertheless, keep a close eye on the mid-late week forecast as confidence increases with respect to the front's position and whether a wetter outcome becomes more or less likely.

AVIATION /12Z SATURDAY THROUGH WEDNESDAY/

High confidence through the 12Z TAF period. A strong cold front moving through early this AM will bring MVFR cigs thru about 14Z, mainly in NC. Any showers will be light and thus no bring any significant vsby restrictions. Otherwise, gusty N winds up to around 30 kt are expected through the afternoon.

Extended Forecast...VFR conditions should prevail, although there will be low chances for minor restrictions starting Sun as low-level moisture begins to increase, mainly due to early morning fog/stratus.

MARINE

Through Tonight...High confidence. Hazardous marine conditions expected through the period due to a strong pressure gradient and cold advection behind a strong cold front, especially today when gale force gusts will occur. Winds will ease a bit tonight but still in the Small Craft Advisory range. Seas should reach up around 7 ft out toward 20 nm offshore with little to no improvement tonight due to the more favorable NE fetch.

Sunday through Wednesday... High pressure will dominate the period with winds veering from northeasterly on Sunday to southeasterly on Monday, then southerly from late Monday through Wednesday. Speeds of 15-20kts early Sunday will decrease through the day, ending up around 10kts or less from Sunday night onward. As max temps on land rise on Tuesday and Wednesday, expect the sea breeze to result in locally enhanced winds nearshore.

Seas will be initially in the 3-6 ft range, but on a declining trend through Sunday, with 6 ft seas expected to exit by sunset in all 20nmi coastal water zones. These waves will be primarily driven by a combination of an ENE swell with a period around 9 sec and ENE wind waves with a period around 5 sec, although the wind waves will subside in the morning as winds decrease and the swells will gradually decline through the day as well. 2-4 ft seas are then expected to remain in place through Wednesday due to a persistent southeasterly swell with a period around 7 sec. Wind waves will contribute little to the overall wave spectrum, except for perhaps some wind chop in nearshore areas, where the sea breeze enhances wind speeds.

ILM WATCHES/WARNINGS/ADVISORIES

NC...Freeze Watch from late tonight through Sunday morning for NCZ087-096-105. SC...Freeze Watch from late tonight through Sunday morning for SCZ017-024. Red Flag Warning until 8 PM EDT this evening for SCZ017-023- 024-032-033-039-054>056-058-059. MARINE...Gale Warning until 6 PM EDT this evening for AMZ250-252-254- 256.