Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
075 FXUS62 KCHS 010552 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 152 AM EDT Tue Sep 1 2026 .WHAT HAS CHANGED... All Key Messages and sections were updated. && .KEY MESSAGES... - 1) Below normal rain chances through Friday with increasing rain chances over the weekend. - 2) Hot and humid conditions return today and continue into the weekend. && .DISCUSSION... KEY MESSAGE 1: Below normal rain chances through Friday with increasing rain chances over the weekend. Today: The broad upper-level anticyclone centered over central Tennessee this morning will steadily expand east and southeast today with 500 hPa heights across the Southeast U.S. poised to rise about 10-20 meters. RAP soundings still have no indication of a subsidence inversion developing today, but the net moisture values throughout the column will become noticeably drier with PWATs progged to drop into the 1.75-1.95 range by late afternoon. The combination of drier air aloft and the lack of any significant forcing mechanism suggest the risk for showers/tstms will be low with only parts of the lower-middle Georgia coast really the only spots where moisture looks to remain sufficient enough to support some degree airmass driven convection. Any moist updrafts that try to initiate outside of this area should quickly entrain a significant amount of dry air and choke off before maturing. 20-30% pops were highlighted along/south of a Glennville-Hinesville-Keller line with pops <10% elsewhere. The sea breeze looks to remain fairly progressive today so the risk for miscible rainfall in this area should quickly end by mid-afternoon. Tuesday through Labor Day: The 595 dm upper-level anticyclone will become positioned across the Carolinas by mid-week and linger into Friday. This will keep a fairly hot, dry and subsident environment in place with a progressive resultant sea breeze likely to occur each afternoon. There may be just enough 850 hPa theta-e return along the southwest flanks of Atlantic high pressure centered well offshore to allow for isolated to perhaps scattered showers/tstms to develop by Thursday and Friday (mainly Southeast Georgia), but much will depend on exactly where the center of the upper high becomes situated. Rain chances will increase over the Labor Day holiday weekend as broad troughing develops across the eastern CONUS and a cold front approaches and possibly drops southward through the Southeast States. KEY MESSAGE 2: Hot and humid conditions return today and continue into the weekend. The ridge of high pressure aloft will also keep temperatures on the warmer side throughout the week, with the warmest temperatures expected on Saturday. As the region slides under the eastern edge of the ridge today, temperatures will peak in the upper 80s along the coast and in the lower to mid 90s inland, with heat index values in the mid 90s to lower 100s. Expect very similar temperatures for Wednesday through Friday as the ridge axis continues to slide towards the east coast, though if the ridge axis slides further to the south then slightly warmer temperatures would be expected. The warmest day is expected on Saturday as the ridge begins to weaken and move westwards while a trough builds along the east coast, with widespread temperatures in the mid 90s with isolated spots in the upper 90s. Combined with dewpoint temperatures in the mid to upper 70s, heat index values in the 105 to 110 degree range may require a Heat Advisory across the coastal corridor on Saturday. Rainfall chances will continue to be closely monitored on Saturday, as earlier development would limit daytime heating and thus result in cooler temperatures. A cold front looks to push through on Sunday, bringing an end to this stretch of hot and humid conditions. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... 01/06z TAFs: KCHS/KJZI/KSAV: There may be a brief period of LIFR cigs at KCHS and possibly KJZI just before daybreak. TEMPO groups for BKN003 cigs were highlighted 10-12z. Winds are expected to increase a bit during this time as a weak coastal trough peaks in intensity just before daybreak. This may keep any stratus build-down processes at bay and limit the fog potential. At KSAV, shallow ground fog may develop just before daybreak which may also yield a little stratus. Conditions were kept VFR for now. Otherwise, VFR will dominate at all three terminals through 02/06z. Extended Aviation Outlook: Isolated showers and thunderstorms may bring brief flight restrictions on Thursday and Friday for southeast Georgia during the morning and afternoon hours. Regional chances for scattered showers and thunderstorms return Saturday afternoon. && .MARINE... Through Tonight: There are no concerns. Northeast winds will back more easterly at the coast this afternoon as the sea breeze forms and moves inland. East winds this evening will gradually back to the northeast again near the beaches late. Winds look to remain 10 kt or less through the period with seas 3 ft or less. Wednesday through Sunday: Expect conditions to remain well below Small Craft Advisory levels this week with light onshore flow becoming slightly enhanced (10-15 kt) along the coast as daily sea breezes develop, then shift inland. 3-4 ft seas on Wednesday slowly subside to 2-3 ft during the second half of the week. Thunderstorm chances could also increase across local waters on Thursday with sfc troughing, with regional chances for scattered showers and thunderstorms returning Saturday afternoon. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$