499 FXUS62 KCHS 232155 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 555 PM EDT Sun Jun 23 2019 .SYNOPSIS... High pressure will gradually build across the Southeast through Tuesday. A front will stall over the area Wednesday and Thursday before high pressure rebuilds. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... Based on recent trends and latest guidance from the HRRR, we have increased PoP into the solid chance range over Georgia and for Allendale and Hampton County, but maintaining slight chance elsewhere through the evening. Convection continues to develop in response to a nearby cold front near the Altamaha River, and spreads east-southeast with the mean steering flow. Given that the overall thermodynamics aren't that impressive, we feel that any risk of severe weather is near zero. But since we've seen some strong winds in the 35-45 mph range not far outside the CWA, and with DCAPE still as high as 800-900 J/kg, we can't entirely rule out a few storms with similar winds through 8 or 9 pm, mainly across Georgia. Previous discussion... Latest surface analysis and visible satellite indicates a weak low pressure near the Grand Strand with an associated cold front arching from SE GA into middle GA. A few clusters of thunderstorms have developed along and south of the front. To the north, cumulus development has remained limited to the Charleston Tri-County area and along the Altamaha River corridor. Latest SPC mesoscale analysis indicated 25-75 J/kg of CIN between the cumulus fields. Latest runs of the HRRR indicates that convection sourced from the upper Savannah River area will approach SE GA this evening. However, the storms will approach around sunset and the BL will likely stabilize. I will limit chance PoPs for showers and thunderstorms to SE GA and across portions of the CHS Tri-county late this afternoon and early this evening. Tonight, convective activity should end by mid evening, the rest of the night will remain dry. Low temperatures are forecast to range from the mid 70s inland to the upper 70s along the coast. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... Fairly strong NVA resulting from a shortwave ridge along with westerly BL flow should limit convective coverage on Monday. The sea breeze will likely be pinned at the coast until late in the afternoon. We maintained isolated PoPs along the coast where sea breeze convergence might overcome the cap. Highs are expected to reach the mid to upper 90s though dewpoints will likely mix down into the 60s inland. We can't rule out a few spots seeing heat indices touch 105F for a few hours, mainly in the coastal corridor. A shortwave will move through Monday night, potentially bringing a decaying MCS into western areas late in the evening. Current indications are that the convection will dissipate before making much progress into our area. Slightly drier air, mid-level capping and westerly BL flow will preclude convection on Tuesday. Highs will be in the mid to upper 90s but slightly lower dewpoints should keep heat indices below 105F. Wednesday should see slightly more afternoon/evening convection as the upper ridge breaks down and an onshore flow develops, thus allowing for an earlier sea breeze. Highs will be in the mid 90s. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... Surface troughing will prevail across the Southeast. This will bring our area the typical afternoon/evening showers and thunderstorms. && .AVIATION /22Z SUNDAY THROUGH FRIDAY/... VFR conditions are forecast through the 18Z TAF period for KCHS and KSAV. The chances for deep convection appear too limited to mention in the TAFs. The greatest chance for showers and thunderstorms will remain over extreme SE GA. Extended Aviation Outlook: Brief flight restrictions are possible in afternoon/evening showers/thunderstorms. && .MARINE... Weak low pressure will remain centered near the Grand Strand of SC this evening, then tracking slowly ENE late tonight. To the south, broad sfc high pressure will remain centered over the eastern Gulf of Mexico. This pattern should yield steady southwest winds, around 10 knots. Seas are forecast to range from 1 to 2 feet. A weak front will stall across the waters mid-week before high pressure rebuilds late week into next weekend. Winds/seas will remain below advisory thresholds. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM... SHORT TERM...JRL LONG TERM... AVIATION... MARINE...