898 FXUS62 KCHS 170817 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 417 AM EDT Thu Apr 17 2025 .SYNOPSIS... High pressure will build into the region today and remain the primary feature through the weekend and into early next week. && .NEAR TERM /THROUGH TONIGHT/... Today: Aloft, a large trough will continue to exit farther off the Northeast Coast while broad ridging expands across the Southeast United States from the west. At the sfc, the local area will remain along the southwest edge of high pressure centered off the Mid- Atlantic Coast. The pattern supports a dry northwest downsloping flow across the region today, while light westerly sfc winds turn northeast late morning, then southeast early-mid afternoon once a weak sea breeze takes shape and shifts inland. A full day of sunny conditions along with deep layer ridging will result in warmer temps than the previous day, generally peaking in the upper 70s to around 80 degrees inland (warmest across Southeast Georgia). Temps should remain in the low-mid 70s closer to the coast as southeast winds across slightly cooler waters brings cooler air to the beaches. Tonight: Aloft, high pressure expands across the region with a ridge axis placed across the Deep South. At the sfc, the local area remains along the southwestern edge of high pressure centered off the Mid-Atlantic Coast. The setup supports light southeast winds across the local area initially, but expect winds to decouple fairly quick after sunset. Light calm/winds under clear skies sets up another night of radiational cooling, but low temps are expected to remain warmer than the previous night. In general, temps should dip into the low/mid 50s inland to low-mid 60s near the coast. && .SHORT TERM /FRIDAY THROUGH SUNDAY/... Ridging in the mid-levels and surface high pressure will dominate the synoptic pattern through the weekend. The center of the surface high pressure will be located over the Western Atlantic, building into the region from the east. A rain-free forecast has been maintained, with plentiful sunshine Friday and Saturday giving way to cloudier conditions on Sunday. Temperatures each day will reach into the mid to upper 80s, with overnight lows inland in the upper 50s and low 60s along the coastline. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... The ridging aloft and high pressure at the surface will continue to dominate into early next week. The pattern then shifts slightly as a mid-level trough swings eastward toward the Great Lakes. Diurnally driven showers and thunderstorms are possible next week, mainly in the afternoon hours associated with the afternoon sea breeze. The current forecast features PoPs generally 20-30% Tuesday and Wednesday afternoons. As these showers and thunderstorms will be diurnal in nature, the overall severe threat remains low. Temperatures are forecast to remain above normal through the period. && .AVIATION /08Z THURSDAY THROUGH MONDAY/... VFR conditions will prevail at KCHS/KJZI/KSAV terminals through 06Z Friday. Extended Aviation Outlook: Prevailing VFR. && .MARINE... Today and Tonight: Aloft, a large trough will continue to exit farther off the Northeast Coast while broad ridging expands across the Southeast United States from the west today and through the night. At the sfc, the local area will remain along the southwestern edge of high pressure centered off the Mid-Atlantic Coast. The pattern will favor quiet conditions across local waters, with westerly winds 5-10 kt early turning northeast this morning, then becoming southeast/east this afternoon as a sea breeze develops and shifts inland. Seas will be no larger than 1-2 ft. Friday through Tuesday: High pressure will build into the region through the weekend. Prevailing high pressure will yield tranquil marine conditions, with winds around 10 to 15 knots and seas averaging 2 to 4 ft. Gusts along the direct coastline and the Charleston Harbor could surge each afternoon to around 20 knots due to the afternoon sea breeze. && .FIRE WEATHER... For today, another round of relative humidity values dipping into the 20-25 percent range is expected. The best chance for these values will be across interior Southeast GA this afternoon, co- located with drier fuels. However, winds will not be a concern with speeds generally 10 mph or less in most areas, especially inland. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...DPB SHORT TERM...CPM LONG TERM...CPM AVIATION...CPM/DPB MARINE...CPM/DPB