FXUS62 KCHS 080057 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 857 PM EDT Tue Jul 7 2026 .WHAT HAS CHANGED... Key Messages have been updated to remove heat/humidity and strong to severe thunderstorms this evening. The Aviation Section has been updated for the 00Z TAF issuance. The Marine Section has been updated to reflect ongoing conditions. && .KEY MESSAGES... - 1) Hot and humid conditions will persist through much of the week. - 2) Typical summertime afternoon and evening thunderstorms this week. && .DISCUSSION... KEY MESSAGE 1: Hot and humid conditions will persist through much of the week. The heat and humidity will build Wednesday as ridging aloft strengthens. 850 hPa temperature are forecast to warm to 20-22C with low-thicknesses peaking 1437-1440 meters. These values typically support highs within a 1-2 degrees either side of 100 degrees. Dewpoints are expected to mix out somewhat (lower-mid 70s) during the afternoon, but dewpoint pooling (upper 70s/lower 80s) near/behind the sea breeze should push heat indices to dangerous levels across parts of the coastal corridor with max heat indices peaking in the 112-116 degree range for several hours. Farther inland, heat indices should generally peak 105-110 range. Given the above noted trends, an Excessive Heat Watch has been posted for the coastal corridor, including both the Charleston and Savannah Metro areas, with a Heat Advisory for much of interior Southeast Georgia into Southeast South Carolina. Only the area from Jenkins County to Hampton County look to fall short of the 108 heat index criteria for a Heat Advisory. Warming temperatures aloft will help limit afternoon convection with only isolated coverage expected. There are some CAMs that support a bit more coverage so this will need to be watched as some areas could fall short of warning/advisory criteria if convection becomes more scattered. Heat is expected to continue through the end of the week with heat indices likely around the 105 to 110 range and highs in the mid to upper 90s area wide. Heat products look to continue at least through Thursday and possibly into Friday with the highest probability of reaching advisory criteria mainly east of I-95 and closer to the coast including the Charleston and Savannah metro areas. While heat indices may not be as high as early week, the bigger issue will be long duration heat stress mainly along the coastal areas where heat indices might not drop to below 100 degrees until well into the evening and overnight hours with lows in the upper 70s to low 80s. Several days of intense heat and minimal cooling overnight has been reflected in the HeatRisk product with widespread Major (level 3 of 4) and a corridor of Extreme (level 4 of 4) along the immediate coast Thursday and Friday. Regardless of any heat products this will continue to bring a risk of heat-related impacts, especially to those more vulnerable to heat or those without adequate cooling/hydration. KEY MESSAGE 1: Typical summertime afternoon and evening thunderstorms this week. The region will be situated between high pressure offshore and a trough of low pressure inland through much of the week, with ridging the primary feature aloft. Larger scale forcing is lacking, but isolated to perhaps scattered showers and thunderstorms will be possible each day largely due to daytime heating and mesoscale boundaries like the sea breeze. Coverage will be highest in the afternoon and early evenings, before dwindling after sunset with loss of insolation. While the environment favors mainly pulse-type convection, a couple strong to severe storms with damaging wind gusts cannot be ruled out. Locally heavy rainfall is also possible with any storms, but flooding risk is low especially given the hot and dry conditions of late. Rain chances will likely increase Sunday into Monday as a more potent shortwave trough moves across the mid-atlantic. Expect storm coverage to increase Sunday afternoon compared to the normal summertime pattern. Storms will likely be focused along a sagging front that will slowly drift south with time. Given the increased coverage and maybe a little more deep layer flow, a couple strong to severe storms with damaging winds may be possible on Sunday. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... VFR conditions are expected to prevail at CHS/JZI/SAV terminals through 00Z Thursday. However, an isolated shower/thunderstorm could impact any terminal Wednesday afternoon. Timing and confidence remain too low to mention showers/thunderstorms in the latest TAF issuance. Extended Aviation Outlook: There will be a risk for tstm impacts at the terminals each afternoon/evening, especially at KCHS and KSAV. && .MARINE... Through Tonight: The pressure pattern should support south-southwest winds between 15 to 20 kts, with a few gusts up to 25 kt near the coast this evening. Given the limited duration and spatial coverage of stronger gusts, have opted to keep local waters out of Small Craft Advisories. Seas should range between 2-4 ft, but slowly subside about a foot late tonight. Wednesday: A southerly flow regime will prevail with some sea breeze enhancements likely along the land/sea interface and Charleston Harbor where gusts near 20 kt will be possible. A typical summer time nocturnal surge will impact the area Wednesday night with south to southwest winds 15-20 kt. Gusts could near 25 kt at times, but durations do not quite look frequent enough for a Small Craft Advisory at this time. && .CLIMATE... Record High Temperatures: July 8: KCHS: 100/2016 KSAV: 101/2010 July 10: KCHS: 100/1986 KCXM: 99/1986 July 11: KCXM: 100/2001 July 12: KCXM: 97/1966 Record High Minimum Temperatures: July 7: KCHS: 80/2017 KCXM: 82/2022 KSAV: 80/1883 July 8: KCHS: 82/2016 KCXM: 83/2016 KSAV: 80/1990 July 9: KCHS: 80/1998 KCXM: 85/1998 KSAV: 80/1883 July 10: KCHS: 81/1986 KCXM: 82/1986 July 11: KCHS: 80/2016 KCXM: 82/2016 July 12: KCHS: 79/2020 KCXM: 82/1998 && .CHS WATCHES/WARNINGS/ADVISORIES... GA...Heat Advisory from 11 AM to 7 PM EDT Wednesday for GAZ099>101- 114-115-137-216-238-240. Extreme Heat Watch from Wednesday morning through Wednesday evening for GAZ217>219-239-241. SC...Heat Advisory from 11 AM to 7 PM EDT Wednesday for SCZ043-044- 147. Extreme Heat Watch from Wednesday morning through Wednesday evening for SCZ045-148>152. MARINE...None. && $$