textproduct: NWS Wilmington

WHAT HAS CHANGED

Forecast highs Monday have been increased by 1-2 degrees inland and by 2-3 degrees near the coast. Uncertainly remains large concerning the potential for shower/thunderstorm development along the incoming Canadian cold front Monday evening. A Small Craft Advisory is being issued for the North Carolina coastal waters for a the surge of northeast winds behind the front Monday night.

KEY MESSAGES

1) Low chances for a shower or thunderstorm will continue this afternoon and again Monday evening along the coast.

2) Unseasonable heat may break record highs at Wilmington and Myrtle Beach Monday.

3) A modified Canadian airmass will bring cooler temperatures and drier conditions to the area beginning late Monday night.

DISCUSSION

KEY MESSAGE 1...Low chances for a shower or thunderstorm will continue this afternoon and again Monday evening along the coast.

Convergence between the northward-moving seabreeze front over Brunswick/southern New Hanover counties and the synoptic westerly wind is kicking off scattered showers across the Cape Fear area. It's possible a thunderstorm or two could appear here through early this evening, but increasingly warm/stable conditions aloft are interfering with this process.

After dry conditions develop tonight and through most of Monday, the arrival of a Canadian cold front from the northeast Monday evening may kick off a few more showers or thunderstorms. Despite good convergence and moisture within the boundary layer, even drier air aloft could hamper coverage. There's little agreement between 12z CAMs and the new RRFS concerning shower location or chances Monday evening.

KEY MESSAGE 2...Unseasonable heat may break record highs at Wilmington and Myrtle Beach Monday.

Temperatures should rise into the 90s one last time Monday. A surface trough should drift offshore early Monday morning leaving light northwesterly winds in place throughout the day. This will hold the seabreeze back and allow hot air to push all the way down to the beaches. Our forecast high of 94 in Wilmington would tie the record set back in 2010, and our forecast high of 91 at North Myrtle Beach would break the record set back in 2020. Florence and Lumberton should remain a few degrees shy of their records. Heat indices are forecast to top out in the upper 90s to around 100 inland, with some 101-103 readings possible within higher dewpoints near the coast.

KEY MESSAGE 3...A modified Canadian airmass will bring cooler temperatures and drier conditions to the area beginning late Monday night.

A refreshing surge of cooler, drier northeast winds will spread in behind the front Monday night. Daytime highs Tuesday through Thursday should remain in the 80s, but the real change will be apparent with overnight lows. For locations away from the coast, forecast lows are in the 60s Monday night through Friday night.

Our forecast low Tuesday night in Wilmington is 64, the coolest in over 3 months!

AVIATION /18Z SUNDAY THROUGH FRIDAY/

Morning low stratus inland has lifted into a cumulus deck with bases as low as 3000 feet. As this afternoon's seabreeze front moves inland and intercepts this rich low-level moisture field, isolated showers/thunderstorms may develop near the coast. Over the past 24 hours model trends have been for less coverage overall, but I plan to continue to mention PROB30 for TSRA in Wilmington through 21z.

VFR conditions are expected overnight with only a low potential for late night ground fog at KFLO, KILM, or KLBT. VFR conditions should persist after sunrise Monday.

Extended Outlook...A low potential exists for brief showers to affect the coastal airports Monday evening as a Canadian cold front moves through from the northeast. Behind the front, VFR conditions should persist through Friday in a drier and cooler airmass.

MARINE

Tonight through Friday...Light to moderate mainly southwest winds are expected from this afternoon through tonight with scattered showers or thunderstorms expected north of Cape Fear where stronger winds aloft are pushing convection developing along the seabreeze front eastward. Surface wind directions should veer northwesterly by Monday morning in advance of a Canadian cold front that should sweep across the entire marine area Monday between 8 pm Monday and 2 am Tuesday.

This front will be pushed southward by the strongest Canadian high, around 1030 mb, we've seen since last spring. The surge of northeasterly winds behind the front is expected to reach 20-25 knots across the Cape Fear coastal waters and a Small Craft Advisory is being issued with this forecast package. Models paint similar conditions along the South Carolina coastal waters later Monday night, but after collaboration with NWS Charleston we'll hold off on an advisory that far south just yet given the more extended timeframe.

Breezy northeast winds should continue through at least Tuesday before weakening somewhat. Directions should remain east to northeast through Thursday.

ILM WATCHES/WARNINGS/ADVISORIES

NC...None. SC...None. MARINE...Small Craft Advisory from 8 PM Monday to noon EDT Tuesday for AMZ250-252.