textproduct: NWS Wilmington

WHAT HAS CHANGED

Severe Thunderstorms Watch 530 in effect for inland counties thru 1am edt Wed.

Lower Cape Fear River minor flooding from Wilmington southward good thru midnight tonight. Forecast to peak at 5.9 ft mllw. Threshold for minor flooding is 5.5 ft mllw.

Moderate rip current risk for Brunswick County Beaches only for Wed.

Aviation discussion updated to account for the 00Z TAFS Issuance.

KEY MESSAGES

1) Strong storms possible this evening/tonight.

DISCUSSION

KEY MESSAGE 1...Strong storms possible this evening/tonight.

KEY MESSAGE 1 DESCRIPTION... Storms firing in the upstate region of the Carolinas/Appalachian mountains benefiting from both warm advection and some increasingly vort-laden northwesterly mid level flow. These storms should meander over those locations in the very near term before they start to congeal into a forced line that moves southward. The RRFS (a well initialized model at this time) brings the storms into northern zones by 00Z clearing the Grand Strand area close to 04Z. And while this sense of timing may work out just fine NW flow-forced lines tend to be quicker than progged and so shaved about 2 hours off of aforementioned windows. Timing is not the only uncertainty with the line as it arrives, so too is the severe potential. DCAPE and MLCAPE will be maintained but also both be waning with the loss of daytime heating. 0-3km SRH remains in the 200-250 range. Mid level lapse rates are forecast to remain quite poor and thunder PROBs stay quite low. One area of slightly enhanced concern is along the immediate coast (NC moreso than SC) where composite convective indices jump right as the line comes through. The RRFS Supercell Composite rises into the 10-15 range in the Cape Fear Region from about 22-01Z. Combining these ingredients could be suggestive of fairly low to medium height storms that may not be the lightning producers that we saw last weekend, but there could still be enough storm structure or even weak LL mesos that put down wind damage. The tornado threat continues to be small but non-zero as cloud bases have trouble getting below about 4kft.

AVIATION /00Z WEDNESDAY THROUGH SUNDAY/

Initially VFR conditions. Cold front and upper impulse to combine to produce scattered convection as both systems drop southward. SVR Watch 530 in effect thru 05Z Wed and affects LBT and FLO terminals only. Have timed the potential severe activity affecting the inland terminals between 01Z and 04Z. Conditions across SE NC and NE SC not all primed for convection given latest CIN across the FA as well as loss of heating and with much of the day encased in smoke aloft and convective debris mid and upper level clouds. Nevertheless, will end the convective and associated flight restriction threat by 06Z for FLO/LBT and 09Z for ILM/CRE/MYR. Will deal with mid/upper level debris clouds early Wed that should give way to just cirrus and FEW/SCT diurnal cu/sc clouds Wed aftn/evening. Active SW winds 5 to 10 kt inland, 10-15 g20+ at the coastal terminals this evening will slowly veer to the W then NW and diminish to less than 10 kt overnight. Winds generally NW 5 to 10 kt after FROPA early Wed. The coastal terminals could see winds back to the S around 10 kt mid aftn into the evening.

Extended Forecast...VFR conditions should dominate Wednesday Night through Saturday. Flight restrictions possible Sun from convection associated with a frontal boundary snaking back northward.

MARINE

Tonight through Saturday... The most unsettled weather of the forecast will be at its beginning. The approach of a cold front will tighten the gradient through early Wednesday. A marginal SCA is in effect through then after which time the boundary moves through and winds/seas both start to abate. The remainder of the period could very well feature winds capped at 10 kt and short period wind waves of less than 3 ft as the pressure pattern remains weak due to a broad trough extending SW into the region from a slow moving storm system trying to exit the midAtlantic region, its progress slowed by the fact that it spends time under a cutoff low aloft.

ILM WATCHES/WARNINGS/ADVISORIES

NC...Coastal Flood Advisory until midnight EDT tonight for NCZ107. SC...None. MARINE...Small Craft Advisory until 8 AM EDT Wednesday for AMZ250-252- 254-256.