textproduct: NWS Wilmington

WHAT HAS CHANGED

An offshore mesolow could lead to a risk of flash flooding, particularly for coastal SE NC, this morning into midday. Updated 12Z TAF discussion below.

KEY MESSAGES

1) Heavy thunderstorms capable of isolated flash flooding remain possible today, mainly near the coast.

2) Near-normal temperatures expected in the long-term with low rain chances for Sunday/Monday increasing midweek.

DISCUSSION

KEY MESSAGE 1...Heavy thunderstorms capable of isolated flash flooding remain possible today, mainly near the coast.

A stalled front offshore will lift back towards the coast early this morning as a surface mesolow and attendant mid-level vort max tracks northeastward along it. This mesolow is expected to pass near Cape Fear in the mid-late morning hours, bringing a renewed threat for heavy thunderstorms and flash flooding, especially over the Wilmington metro area. Behind this mesolow, heating of a moist airmass and additional impulses moving around the broader trough in the jet stream should aid in the development of scattered showers and thunderstorms this afternoon, particularly along the sea breeze. Showers and thunderstorms will remain possible near the immediate coast and offshore tonight as impulses aloft interact with instability over the very warm ocean. However, if sufficient outflow pushes offshore this afternoon, the threat along the coast will be lowered.

KEY MESSAGE 2...Near-normal temperatures expected in the long-term with low rain chances for Sunday/Monday increasing midweek.

Another cold front is expected to be push in from the northwest Sunday afternoon, keeping a chance for isolated to perhaps scattered showers and thunderstorms, mainly along the coast. A period of mostly dry weather appears likely on Monday with the front stalling offshore. However, as the flow aloft becomes westerly to northwesterly around midweek and the stalled front lingering over or near the area, additional impulses and waves of low pressure are poised to bring periods of showers and thunderstorms from Tuesday onward, with the best chances for more widespread rain currently focused on Thursday into Friday. Of course, given this is multiple days away, the chances for rain will likely fluctuate in the coming days as smaller-scale details are worked out.

AVIATION /12Z SATURDAY THROUGH WEDNESDAY/

CIGs should be an issue for inland terminals during the first several hours of the TAF period, clearing by 16-18Z. Meanwhile, coastal terminals may see an increase in showers/storms this morning, mainly KILM. Have added TEMPOs for diminished conditions in heavy rainfall. ~18Z we'll return to typical scattered showers/storms with the sea breeze so have PROB30s for those. At the moment haven't included any restrictions for past 00Z, but inland could see fog/stratus again Saturday night.

Extended Forecast... Mostly VFR expected. Low risk for transient restrictions from showers/storms Sun/Mon with a bit better risk Tue/Wed, especially near the coast.

MARINE

Today through Wednesday... Expect generally south to southwest winds to prevail through the period as an approaching cold front stalls near the coast. No headlines are expected as winds peak around 15-20 kts over Saturday night and wave heights stay around 3 ft or less within 20 nmi and up to 4 ft in the 20-60 nmi zones, highest this weekend.

The biggest marine impact will likely be from scattered to numerous showers and thunderstorms over the waters through the weekend as a front stalls near the coast. There will likely be several rounds of storms, accompanied by reduced visibility and possible gusty winds.

ILM WATCHES/WARNINGS/ADVISORIES

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