422 FXUS62 KCHS 222339 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 739 PM EDT Sat Jun 22 2019 .SYNOPSIS... A stationary front will remain across the region through this weekend. High pressure is expected to build over the Southeast early next week. A cold front is forecast to slowly move across the Coastal Plain Wednesday into Thursday. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... As of 735 PM: Deep convection should push north of Berkeley and Charleston Counties over the next 45 mins. Once these storms pass, the threat for severe weather should end over the CWA. As of 650 PM: I will update the forecast to remove all Georgia counties, Georgia waters from Severe Thunderstorm Watch 424. In SC, I will remove Allendale, Hampton, Jasper, and Colleton Counties from the watch. As of 615 PM: Convection has largely shifted along the coast between Savannah and the Charleston Harbor. This activity should surge east over the waters, with likely 50 kts wind gusts. Near the I-26 corridor a well defined gust front was tracking north. This boundary should trigger additional storms, potential severe wind gusts. To the west across SE GA, the area will continue with stratiform rain with embedded thunderstorms. This area has been worked over and the severe threat has likely ended. The convective activity has cooled temperatures across the CWA, Heat Advisory has ended. As of 350 PM: Latest visible satellite indicated deep convection developing over SE GA with very limited cumulus developing over the SC Lowcountry. Recent sfc observations indicate that temperatures generally ranged in the mid 90s across the region, with dewpoints in the mid to upper 70s common across SE GA and the southern portions of the SC Lowcountry. Recent SPC mesoscale analysis indicated that most of the SC counties remained under 25-75 J/kg of CIN. Near term guidance shows the llvl CIN eroding over the next 1 to 2 hours. Thunderstorms, severe thunderstorms, across SE GA will continue to develop into this evening given CAPE in excess of 5000 J/kg and DCAPE greater than 1000 J/kg. The arrival of outflows and increase destabilization should result in rapid develop across the SC Lowcountry later this afternoon. Severe thunderstorms, capable of damaging wind gusts and hail, should continue over the region through 9 PM, highlighted with Severe Thunderstorm Watch 424. In addition, a Heat Advisory will remain in effect until 6 PM, cooled by thunderstorm cold pools. Scattered to isolated thunderstorms are forecast to continue across the region tonight. Low temperatures should range in the low to mid 70s. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/... The active northwest flow convective pattern will likely persist through Sunday evening as a series of shortwaves drop southeast through the area. The warmest temps will be across southeast GA and far southern SC where the combination of low/mid 70s dewpoints will produce robust instability. Model soundings indicate potentially less mid-level dry air than Saturday but there will still be the potential for some severe thunderstorms. The best chance will be across southeast GA where the greatest instability exists but with the stronger shortwave energy moving out of SC we could also see some strong/severe storms moving through southern SC at some point Sunday. Also, heat index values could top 105F for a few hours along the GA coast. Considerable mid-level subsidence is anticipated on Monday as the shortwave ridge axis shifts overhead and spreads widespread NVA over the area. We maintained a slight chance for showers and tstms mainly to account for possible sea breeze convection in the afternoon. Highs in the mid to upper 90s and moderate dewpoints could produce 105-108F heat indices along a corridor near the coast in SC/GA where the afternoon dewpoints are less likely to mix out. Slightly better convective coverage is anticipated on Tuesday as the upper ridge begins to break down. Another hot day is in store with highs in the mid to upper 90s and heat indices 100-105F. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... A stationary front or weak inland trough will prevail across the Southeast. This will bring our area the typical afternoon/evening showers and thunderstorms. Based on the latest information, it appears that the greatest risk for thunderstorms will occur between 21Z to 1Z, greater chance at KSAV. Until then, expecting gusty WNW winds from late morning through this afternoon. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... Deep convection has pushed north and east of the terminals this evening. Remnant stratiform rain with embedded thunderstorms should continue until 3Z. After the convection passes, VFR conditions should persist through the rest of the 0Z TAF period. Extended Aviation Outlook: Brief flight restrictions are possible in afternoon/evening showers/thunderstorms. && .MARINE... A stationary front will remain over the marine zones through tonight. Thunderstorms sourced over land will push east across the adjacent waters tonight, likely producing gusty winds, hail, and cloud-to-water lightning. Between the storms, winds will favor a SW direction between 10 to 15 kts. Wave heights are forecast to range between 2-3 feet. A stationary front draped over the waters will dissipate by Monday as Atlantic high pressure rebuilds. Another front will approach the waters mid to late next week. Winds/seas will remain below advisory thresholds during the period. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...NED SHORT TERM...JRL LONG TERM... AVIATION...JRL/NED MARINE...JRL/NED