textproduct: NWS Wilmington

WHAT HAS CHANGED

As we approach 7 PM EST, cold front is nearly at the coast, and will be pushing offshore momentarily. Light northerly winds are starting to take shape across the area behind the frontal boundary. The front itself was able to generate one more smaller, broken line of showers and storms, the biggest cluster noted just offshore of Georgetown County. Stratiform showers or sprinkles possible just behind this cluster in northeast SC. Otherwise, the forecast is predominantly dry from here on out.

No major changes to the forecast at this point. Aviation discussion updated below for the 00Z TAFs.

KEY MESSAGES

1) A broken band of showers and storms capable of producing isolated severe storms will cross the area through the late afternoon.

2) Dry weather returns Saturday, accompanied by cooler, more seasonable temperatures through the weekend. Temperatures will moderate to above normal by midweek.

DISCUSSION

KEY MESSAGE 1...A broken band of showers and storms capable of producing isolated severe storms will cross the area through the late afternoon.

The primary pre-frontal band of showers and storms accompanying the advancing cold front is moving faster than earlier forecast and model guidance suggested, and should be largely offshore by 21z. Thus far, the severe wind threat has been somewhat muted by persistent low clouds and weak low-level lapse rates. However, despite these limiting factors, an isolated tornado cannot be ruled out, mainly across the Cape Fear region where the highest low-level and composite severe parameters are currently focused( SCP of 2 and STP of 0.5). Any tornado threat would likely be brief and localized.

A few isolated shower/storms could re-develop behind the primary line, but the overall severe threat should diminish substantially with it's passage as the better forcing and more favorable low-level environment shift offshore.

KEY MESSAGE 2...Dry weather returns Saturday, accompanied by cooler, more seasonable temperatures through the weekend. Temperatures will moderate to above normal by midweek.

Broad troughing across the eastern CONUS will support the southward progression of surface high pressure from the mid MS Valley into the into the SE US through the weekend. This will usher in cooler and drier airmass, bringing a welcomed return to more seasonable temperatures. Afternoon highs Saturday and Sunday will generally range in the mid to upper 60s, while overnight lows dip down into the upper 30s to lower 40s inland and mid 40s along the coast Saturday night and again Sunday night.

As the sfc high gradually shifts southward across the Deep South, light southerly flow will allow temperatures to gradually moderate with highs back up into the lower to mid 70s across the region.

AVIATION /00Z SATURDAY THROUGH WEDNESDAY/

Mostly VFR through the 00Z TAF period. Some MVFR ceilings are bouncing around behind the frontal boundary, particularly at the coast, but these should be temporary. Recent guidance is starting to show a brief, but significant bout of BR or low stratus at KFLO from 04-07Z. Models show visibilities drop down to less than 1SM. Since this is a recent trend, I didn't follow it exactly, and instead compromised on a TEMPO group with VSBY restrictions down to 3SM. Will need to monitor this throughout the night. Skies start to clear out after 06Z.

Gradient winds start picking up around 10Z or so, building towards a decent northerly breeze up to 8-11 kts by 14-15Z. This breeze will come down to 5 kts or so towards the end of the period.

Extended Outlook...Predominantly VFR through Wednesday. Low confidence in fog restrictions early Monday morning.

MARINE

A cold front moves through this evening into the overnight hours for our waters, and ahead of this boundary strong thunderstorms capable of gusty winds and a brief waterspout are possible. Light southerly winds will briefly veer to SWLY just ahead of the frontal passage, followed by post-frontal north/northwest winds, gusting to 15-20 knots. Gusts approaching 25 kt will likely be confined to 20-60 nm zones Saturday.

Seas will build slightly behind the cold front with 3-5 ft nearshore and 4-6 ft offshore persisting through the weekend before subsiding to 2-3 ft nearshore and 3-4ft offshore Monday and Tuesday as sfc high pressure becomes centered over the area.

ILM WATCHES/WARNINGS/ADVISORIES

NC...None. SC...None. MARINE...None.