textproduct: NWS Wilmington

WHAT HAS CHANGED

Forecast remains consistent with few changes.

KEY MESSAGES

- 1) Heavy rain will develop and persist at times through Sunday. A few areas could see flash flooding as a result, especially across coastal areas. Isolated tornadoes are possible tonight into the day Sunday

- 2) Hazardous surf conditions and tidal flooding will continue throughout the weekend.

- 3) Hazardous marine conditions will continue through this weekend.

DISCUSSION

KEY MESSAGE 1...Heavy rain will develop and persist at times through Sunday. A few areas could see flash flooding as a result, especially across coastal areas. Isolated tornadoes are possible tonight into the day Sunday.

Warm frontal zone remains mostly to the south this afternoon but dewpoints and surface temperatures are increasing due in part to diabatic heating from rainfall. Guidance is in fairly good agreement on the front making its way north by 00 UTC as the movement remains slow due to convergence aloft to the northeast and the wedge type of environment. The precipitation characteristic will then shift from more stratiform to convective at this time. The flash flood potential remains in place as the slow movement of the system and the fact that several bands of rainfall with in between showers are expected. Pops overall remain high but expect a lull tonight from near midnight through the early morning hours.

The concern for severe weather moreso tornadoes remains in place due to several factors. First the slow moving nature of the warm front has allowed cells to ingest the favorable dynamics citing the rotating cells offshore today. Unfortunately the threat will continue basically through most of the day Sunday. In fact the Significant Tornado Parameter has high numbers for this time tomorrow across Cape Fear and the timing of day if favorable as is the banding feature of the precipitation from high resolution guidance.

KEY MESSAGE 2...Hazardous surf conditions and tidal flooding will continue throughout the weekend.

No changes to the previous thinking regarding coastal impacts this weekend. The increased onshore winds will yield rough surf and strong rip currents. Large breaking waves of 3 to 7 ft expected along the beaches north of Cape Fear. Wave-runup may also cause minor to moderate beach erosion, especially those beaches with a weakened shoreline structure with high tide this evening. Rough surf may linger into Monday, but should improve as the winds become more favorable.

The winds coupled with the high astronomical tides during the next several high tide cycles will lead to minor coastal flooding along all area beaches and the lower Cape Fear River, including downtown Wilmington.

KEY MESSAGE 3...Hazardous marine conditions will continue through this weekend.

Gale warning remains in place through tonight. Although winds are probably at their peak for this system wind speeds and especially gusts will remain elevated. Expect the warning to be followed by a small craft advisory Sunday. The marine community should be aware of perhaps a special marine warning or two being issued for rotating cells through Sunday.

AVIATION /18Z SATURDAY THROUGH THURSDAY/

MVFR to IFR conditions will persist across the area through the period. Ceilings and visibilities are slowly coming down as the remnants of Isaias remain to the west. The system is obviously slow moving and currently is drifting to the northwest but will eventually make its way eastward. Lightning may be hard to come by especially early in the forecast but may be needed in time especially later Sunday.

Extended Outlook...IFR conditions are likely inland with lower confidence at coastal terminals. Heavy rain and thunderstorms are expected Saturday night into Sunday, higher confidence at coastal terminals. VFR should return as dry air filters in late Sunday through Wednesday.

ILM WATCHES/WARNINGS/ADVISORIES

NC...Flood Watch through Sunday morning for NCZ099-105>110. High Risk for Rip Currents until 8 PM EDT this evening for NCZ106- 108. High Surf Advisory until 8 AM EDT Sunday for NCZ106-108. Beach Hazards Statement until 8 PM EDT this evening for NCZ110. SC...Flood Watch through Sunday morning for SCZ054>056-058-059. High Risk for Rip Currents until 8 PM EDT this evening for SCZ054- 056. MARINE...Gale Warning until 6 AM EDT Sunday for AMZ250-252-254-256-280- 284.