textproduct: NWS Wilmington

WHAT HAS CHANGED

Rain chances have decreased slightly through Friday with little change Saturday through Tuesday.

KEY MESSAGES

1) Temperatures well above normal Thursday through Saturday with heat indices over 100 degrees.

2) Limited rain chances until the arrival of a cold front this weekend.

DISCUSSION

KEY MESSAGE 1...Temperatures well above normal Thursday through Saturday with heat indices over 100 degrees.

KEY MESSAGE 1 DESCRIPTION...Strengthening mid-level ridge will result in temperatures well above normal Thu through Sat. The warming begins today, but temperatures will jump around 5 degrees for most areas on Thu. Peak of the heat will be Fri when mid-level ridging(even though it weakens slightly) combines with westerly flow. This will keep the sea breeze pinned and lead to a little downslope flow/compressional warming. Ridging continues to weaken Sat as a front moves in from the northwest. Increased cloud cover and weakening 5h ridge keep temperatures a little cooler Sat, but still above normal. Continues to look like heat indices will flirt with 105 at some point Thu-Sat, but have low confidence in duration and areal coverage. Something to keep an eye on the next few days.

KEY MESSAGE 2...Limited rain chances until the arrival of a cold front this weekend.

KEY MESSAGE 2 DESCRIPTION...Despite increasing temperatures and dewpoints creeping into the 70s (see Key Message #1) rain chances will be limited into the weekend. Ridging aloft in place into Fri with only a weak shortwave to the north slightly denting the ridge this afternoon/evening. Mid-level environment remains unfavorable for storms with an abundance of dry air aloft, subsidence and poor lapse rates. Cannot rule out some isolated convection along the sea breeze and Piedmont trough, but coverage will be limited by the lackluster environment. About the only parameter working in favor of convection will be surface based instability, with SBCAPE pushing 1k J/kg Thu/Fri. Mid-level ridging does start to weaken Fri, which may open the door for a few more storms, but it's also quite likely that the ridge doesn't weaken quite as quickly and Fri remains more or less dry.

Surface based instability hangs around Sat, when a cold front moves in from the northwest. The front, while not strong, will provide some enhanced low level convergence, coincident with the suppression of the mid-level ridge. Also potential for development of a surface wave along the front later Sat into Sun, enhancing rain chances. Confidence decreases after Sat with the location of the front and moisture availability in question. Sat looks to be the best chance for rain, but there is potential for the 5h pattern to shift from ridging to troughing which would open the door for a period of unsettled weather early next week.

AVIATION /06Z WEDNESDAY THROUGH SUNDAY/

VFR along the coast with MVFR setting up inland. MVFR ceilings at FLO/LBT are a result of left over moisture from earlier convection along the SC coast moving north. Coastal terminals will remain VFR with the enhanced low level moisture staying inland from the coast.

Generally VFR today, once inland sites rise out of MVFR (mid to late morning). Limited coverage of storms today, less so than Tue given the increasing unfavorable environment and have no mention of storms at any of the terminals. Southwest winds under 10kt today at inland sites with the sea breeze leading to a little more onshore flow for coastal terminals. Speeds will also be enhanced by the sea breeze.

Extended Forecast...Restrictions from isolated afternoon/evening storms possible through Friday, mainly inland. Increased daytime coverage of storms this weekend will increase potential for restrictions at all sites. Otherwise VFR.

MARINE

Southwest flow continues into the weekend with Bermuda High in place. Gradient between the high and the developing Piedmont trough will enhance wind speeds, especially Thu and Fri. Nearshore speeds will be 15-20 kt with a solid 20 kt well offshore. Weak cold front drops in from the northwest Sat, but struggles to move offshore. The boundary may end up laying parallel to the flow aloft just north of the waters. Southerly flow continues Sat, but weakens with the front in the area leading to a poorly defined gradient. If the front slips south of the waters at any point Sat/Sun then northerly flow would set up, but weak gradient and the lack of a strong push will keep speeds 10-15 kt at most. If the front remains to the northwest Sun, enhanced southerly flow would be possible for the start of next week. Seas 2-3 ft build to 3-4 ft later Thu before dropping back to 2-3 ft Thu night. Cycle repeats on Fri with 2-3 ft seas returning Fri night then dropping to around 2 ft with occasional 3 ft for the weekend.

ILM WATCHES/WARNINGS/ADVISORIES

NC...None. SC...None. MARINE...None.