textproduct: NWS Wilmington

WHAT HAS CHANGED

All sections updated with little change in forecast thinking. A Heat Advisory has been issued for Saturday.

KEY MESSAGES

-1)Saturday brings one last day of heat as well as late day severe thunderstorms.

DISCUSSION

KEY MESSAGE 1...Saturday brings one last day of heat as well as late day severe thunderstorms.

KEY MESSAGE 1 DESCRIPTION... As with both the last few days but also a good portion of the summer mid level ridging will keep the weather hot for one more day heading into Saturday. A Heat Advisory will be issued for the entire area. Of note the NBM dewpoints were high enough to support warning criteria with HI's in the 110-113 range but forecast soundings show a deep dry sub-cloud layer/inverted V and so these values were trimmed, keeping HI's in advisory realm.

As Saturday progresses the mid level ridge will retreat westward. This will open the area up to height falls and increasingly vort center-laden northwesterly flow coinciding with the approach of a cold front. In the hot, humid airmass instability will grow moderately strong, perhaps in excess of 2000J/Kg and even DCAPE could attain values of 1500, all while deep layer shear increases to 25-30 kts. SPC continues to highlight the entire area in SLIGHT, level 2/5 for severe weather citing damaging wind as the main threat. Some hail may also reach the ground esp over northern counties but some dry air aloft should temper its size. Looking through CAMs the heaviest activity looks to favor the coast and would not be surprised to see a 30" wind isopleth (though this would still be SLIGHT). Lastly as the storms enter the area from the north they will be weakening but early on could still have some impressive lightning flash rates (esp given the fact that NW flow events are often a bit quicker than progged).

AVIATION /00Z SATURDAY THROUGH WEDNESDAY/

VFR conditions should be in place through the period. There remains a low chance for BR across inland areas but with a pattern chance slowly evolving winds may preclude any of this. PROB 30 groups have been added to relevant sites for Saturday afternoon convection.

Extended Outlook...Showers and thunderstorms should become numerous across the area late Saturday afternoon through Sunday as a cold front arrives from the north. The highest potential for IFR conditions in convection and briefly strong winds is expected Saturday evening. Prevailing VFR conditions should return by Monday and Tuesday.

MARINE

Swell energy has abated so now some typical late summertime conditions with SW flow and mainly wind waves along with the weak but still present SE swell. Major changes in store for Labor Day Weekend, a big one for boating. A cold front will approach late tomorrow and while most of the day should be rain-free a line of strong to severe thunderstorms is expected. Storms are expected late afternoon/early evening from N to S. The front will stall near our southern waters Sunday making for light and variable winds while storms continue to bring widespread visibility restrictions and localized gusty winds albeit with less vigor than Saturday. The remainder of the forecast will see high pressure building in from the north bringing N to NE flow that could approach advisory thresholds at least in gusts Sunday. A long onshore fetch develops behind the front that could bring advisory-worthy 6 ft seas Monday.

ILM WATCHES/WARNINGS/ADVISORIES

NC...Heat Advisory until 8 PM EDT this evening for NCZ087-096-099- 105>110. Heat Advisory from 11 AM to 8 PM EDT Saturday for NCZ087-096- 099-105>110. SC...Heat Advisory until 8 PM EDT this evening for SCZ017-023-024- 032-033-039-054>056-058-059. Heat Advisory from 11 AM to 8 PM EDT Saturday for SCZ017-023- 024-032-033-039-054>056-058-059. MARINE...None.