textproduct: NWS Wilmington

WHAT HAS CHANGED

A Small Craft Advisory has been issued for Sunday through Monday.

KEY MESSAGES

1) Wet and unsettled pattern Sunday through at least mid week

2) Strong southerly winds and hazardous marine conditions expected to develop Sunday into Monday.

DISCUSSION

KEY MESSAGE 1...Wet and unsettled pattern Sunday through at least mid week

A potent shortwave trough currently over the Upper/Mid MS Valley will track east-southeast into the Ohio and Tn Valley through the weekend before slowing down and potentially closing off over the SE US/southern Appalachians early next week. The system is then expected to linger while gradually weakening through midweek, before finally lifting off to the NE late in the work week.

Deep southwesterly moisture transport between this slow moving system and subtropical ridging over the western Atlantic will maintain an axis of anomalously moist air, with PWATs of 2.0- 2.50"(125-1505 of normal), across eastern portions of the Carolinas through much of the period. A northward lifting warm front will provide the initial focus for showers and storms on Sunday, with additional daily rounds of convection Mon-Wed aided by embedded shortwave impulses interacting with seabreeze and upper divergence associated with a jet over the Appalachians. As the trough gradually weakens, convective rain chances should transition to a more typical diurnally driven pattern as anomalous moisture remains in place.

This unsettled pattern could provide some much needed drought relief, with widespread rainfall total of 1 to 2 inches expected during the period. Locally higher amounts will be possible where storms repeatedly track over the same area, which could also lead to isolated flooding. Despite widespread cloud cover and generally weak lapse rates, highs in the 80s combined with dew points in the mid to upper 70s should support moderate instability, allowing for an isolated severe threat each day.

KEY MESSAGE 2...Strong southerly winds and hazardous marine conditions expected to develop Sunday afternoon and linger through Monday. See marine section below.

AVIATION /06Z SATURDAY THROUGH WEDNESDAY/

Predominately VFR conditions are expected through the afternoon and evening, though a stray afternoon shower or two cannot be ruled out. Strengthening moisture advection ahead of an approaching warm front from the south will support isolated to widely scattered showers Saturday evening into tonight. In addition, increasing low-level moisture may support the development of areas of low stratus near inland TAF sites towards daybreak Sunday.

Light SELY winds of 5 to 10 kts will increase slightly by the afternoon, with some gusts up to 15-18 kts possible.

Extended Forecast... A slow moving upper trough settling over the region, combined with an anomalously moist airmass, will support periods of showers and storms from Sunday through at least the middle part of next. Periodic sub-VFR restrictions will be possible in heavier showers and thunderstorms. The moist low-level airmass will also support a greater potential for morning stratus each day.

MARINE

Through Wednesday...Southeast winds gradually increase late this afternoon and veer to southerly Saturday night as a stalled front lifts back to the coast. Winds increase considerably on Sunday as the pressure gradient tightens and the front lifts inland, resulting in breezy south winds with gusts likely to pass SCA criteria Sunday afternoon and likely to continue into Monday. Weak winds will yield benign seas between 1-3 ft through Saturday night. Seas rapidly increase to 4-6 ft as winds increase on Sunday and these continue into Monday before relaxing gradually Monday night and Tuesday. Winds come back down towards a moderate breeze Tuesday and Wednesday, while seas gradually improve to 2-4 ft Tuesday and Wednesday.

ILM WATCHES/WARNINGS/ADVISORIES

NC...None. SC...None. MARINE...Small Craft Advisory from noon Sunday to 8 PM EDT Monday for AMZ250-252-254-256.