textproduct: NWS Wilmington

WHAT HAS CHANGED

Gale warning issued for late tonight through Friday afternoon.

KEY MESSAGES

1) Heat advisory for parts of the area today along with increased fire danger.

2) An isolated severe storm possible later today and tonight.

3) Gale warning for all waters starting late tonight through Friday afternoon.

DISCUSSION

KEY MESSAGE 1...Heat advisory for parts of the area today along with increased fire danger.

KEY MESSAGE 1 DESCRIPTION... Heat continues today with heat index values flirting with 105 degrees over northern and eastern portions of the area and a heat advisory remains in effect. Dry and breezy conditions this afternoon with increased fire danger across NC this afternoon.

KEY MESSAGE 2...An isolated severe storm possible later today and tonight.

KEY MESSAGE 2 DESCRIPTION... Although an isolated strong to severe storm is possible later today, the better chances will be overnight tonight. Prior to the arrival of the remnants of Arthur tonight, the environment is less than optimal for convection. Despite precipitable water approaching 2" there is a large amount of mid-level dry air and a weak subsidence inversion. Other than weak convergence along the sea breeze (strongest along the Georgetown coast) forcing remains limited. Expect to continue seeing storms moving into the area from southern and central SC, but struggling to make much headway north. Sea breeze convergence and Piedmont trough/outflow convergence will help with storm development, but again the environment suggests storms will struggle to continue. Forecast soundings show dry air in the low-levels in the form of an inverted V sounding, but the strongest winds in the mixed layer are 25kt or less, about half of what they will be tonight. The combination of 25kt winds/25kt storm motion and low level dry air could lead to isolated strong/damaging wind gusts with the strongest storms, but overall severe potential for the afternoon is a step above zero.

Shortwave associated with the remnants of Arthur will move across the area later tonight. Abundant tropical moisture with the shortwave and surface wave/low coupled with strong divergence aloft will lead to development of deeper convection overnight. The boundary layer will remain well mixed, allowing for surfacing of stronger winds aloft, especially within stronger convection. Low level jet of 50-55 kt will not have much trouble mixing to the surface, suggesting convection with any respectable updraft will have the potential to produce damaging wind. The good news is the overnight timing will limit surface based instability thus areal coverage of deeper convection will be small. Timing in western portions of the forecast area looks to be between midnight and 4AM, pushing off the coast mid to late morning Fri.

KEY MESSAGE 3...Gale warning for all waters starting late tonight through Friday afternoon.

KEY MESSAGE 2 DESCRIPTION... See marine section below.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

Generally VFR with strong, gusty southwest winds being the bigger story. Gusts 25-30 kt not out of the question through the afternoon. An isolated afternoon/evening storm is possible, along with brief MVFR/IFR conditions. Better chances at SC terminals, but overall potential is limited. Remnants of Arthur will move into the area late tonight, accompanied by showers and thunderstorms as well as MVFR/IFR conditions. High confidence in widespread MVFR, could be as early as 07Z for FLO arriving at the coast closer to 12Z, with potential for brief periods of IFR within the MVFR. Anticipate a return to VFR close to the end of the valid TAF period, although confidence is somewhat lower in timing of the return of VFR. Along with the low ceilings strong southwest winds continue tonight with 40-50kt low level jet at times. Enhanced winds within the boundary layer may prevent LLWS from being an issue, but will be something to keep an eye on.

Extended Forecast...MVFR/IFR possible ahead of a cold front Friday night into Saturday. VFR returns later Saturday and continues through Monday.

MARINE

Offshore high pressure and the remnants of Arthur along with a cold front will enhance the gradient later tonight and for much of Fri. Small Craft Advisory continues this afternoon into tonight. Have raised a gale warning for the near shore and offshore waters late tonight through Fri afternoon. Gales probably won't occur over most of the waters, and what is likely to occur will be in the form of gale gusts, outside of the convection that moves offshore during the early morning hours. Although the tropical remnants will move north of the area during the first half of Fri, the approaching front will keep southwest flow around 20 kt through the afternoon. Cold front pushes south of the waters late Fri night with northerly flow setting up for Sat. Not much in the way of northerly surge and the high shifts east by Sun setting up return flow. Southwest flow continues Mon and Tue with diurnal enhancement increasing speeds to 15-20 kt. Seas in excess of 6 ft develop later tonight and remain significant until offshore flow develops following the passage of the front late Fri night. Seas drastically improve for the weekend before starting to build early next week as a more typical summer pattern sets up.

ILM WATCHES/WARNINGS/ADVISORIES

NC...Heat Advisory until 8 PM EDT this evening for NCZ087-096-099- 105-107-109. Beach Hazards Statement until 8 PM EDT this evening for NCZ106- 108. High Risk for Rip Currents until 8 PM EDT this evening for NCZ110. SC...Heat Advisory until 8 PM EDT this evening for SCZ055-058-059. Beach Hazards Statement until 8 PM EDT this evening for SCZ054- 056. MARINE...Small Craft Advisory until 5 AM EDT Friday for AMZ250-252. Gale Warning from 5 AM to 4 PM EDT Friday for AMZ250-252-254- 256-280-284. Small Craft Advisory until 5 AM EDT Friday for AMZ254-256.