441
FXUS62 KCHS 280001
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
801 PM EDT SUN JUL 27 2025
SYNOPSIS
ATLANTIC HIGH PRESSURE WILL PREVAIL EARLY THIS WEEK, WHILE A
TROUGH OF LOW PRESSURE RESIDES INLAND. A COLD FRONT COULD
APPROACH THE REGION LATE WEEK.
NEAR TERM /UNTIL 6 AM MONDAY MORNING/
THE SEA BREEZE CONTINUES TO VERY SLOWLY MARCH AWAY FROM THE
BEACHES AS WE APPROACH SUNSET, WITH LOCATIONS NEAR AND BEHIND
THE SEA BREEZE STILL EXPERIENCING HEAT INDEX VALUES OF 105-110.
OTHERWISE, CLEARING SKIES AND LIGHTS WINDS PREVAILING WILL ALL
CONVECTIVE ACTIVITY REMAINING WELL NORTH OF THE SANTEE RIVER.
TONIGHT: CONDITIONS REMAIN WARM AND MUGGY OVERNIGHT, WITH
TEMPERATURES ONLY FALLING INTO THE MID TO UPPER 70S INLAND AND
STRUGGLING TO FALL BELOW 80 ALONG THE COASTAL CORRIDOR. ONCE AGAIN,
HEAT ADVISORY AND EXTREME HEAT HEADLINES WILL CONTINUE THROUGH THE
NIGHT GIVEN THE LACK OF RECOVERY FROM THE WARM OVERNIGHT
TEMPERATURES.
SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/
HOT TEMPERATURES AND HIGH HUMIDITY IS EXPECTED TO CONTINUE THROUGH
THE PERIOD. HOWEVER, THE HIGHEST TEMPERATURES AND POTENTIAL FOR HEAT
ADVISORIES AND/OR EXTREME HEAT WARNING CONDITIONS ARE EXPECTED TO BE
MONDAY. THE DEEP LAYER RIDGE, CENTERED JUST WEST OF THE REGION, WILL
HANG ON MONDAY, THEN BEGIN TO SLOWLY WEAKEN AND RETROGRADE WESTWARD
TUESDAY AND WEDNESDAY.
MONDAY: AS THE RIDGE SLOWLY WEAKENS/MOVES WESTWARD, A BAND OF DEEP
LAYER MOISTURE WORKS IN FROM THE NORTH AND NORTHWEST. THIS MOISTURE,
ALONG WITH INTENSE AFTERNOON HEATING, AND PRESENCE OF SEABREEZE,
COULD PRODUCE SCATTERED SHOWERS AND THUNDERSTORMS LATE AFTERNOON,
ESPECIALLY AROUND THE CHARLESTON TRI-COUNTY REGION. SCATTERED
SHOWERS AND THUNDERSTORMS COULD PUSH SOUTHWARD LATER IN THE
AFTERNOON, BEFORE DISSIPATING IN THE EVENING. GIVEN INTENSE HEATING
HELPING TO PRODUCE AFTERNOON CAPES OF 1500 TO 2500 J/KG AND DCAPES
AROUND 1000 J/KG, COULD SEE ISOLATED STRONG STORMS WITH GUSTY WINDS.
TEMPERATURES AGAIN EXPECTED TO BE VERY HOT, WITH AFTERNOON HEAT
INDICES LIKELY REACHING EXTREME HEAT WARNING LEVELS OF 113 TO 116
DEGREES FROM THE CHARLESTON TRI-COUNTY REGION, SOUTHWARD DOWN THE
COAST INTO OUR GA ZONES, INCLUDING THE SAVANNAH AREA. WILL LIKELY
REPLACE THE EXTREME HEAT WATCH FURTHER INLAND TO A HEAT ADVISORY,
SINCE WE FEEL MAX HEAT INDICES WILL LIKELY STAY BELOW 113 DEGREES.
TUESDAY AND WEDNESDAY: THE DEEP LAYER RIDGE CONTINUES TO SLOWLY MOVE
WESTWARD. THE DEEP LAYER MOISTURE THAT MOVED INTO THE AREA FROM THE
NORTH ON MONDAY WILL NOW BE STALLED ACROSS THE ENTIRE REGION DURING
THIS TIME FRAME. THUS, THE CHANCES FOR CONVECTION WILL INCREASE,
WITH SCATTERED TO NUMEROUS MAINLY AFTERNOON SHOWERS AND
THUNDERSTORMS EACH DAY. THE INCREASE IN CONVECTIVE POTENTIAL SHOULD
HELP TO KEEP TEMPERATURES A TAD LOWER, LIKELY OUT OF THE EXTREME
HEAT WARNING RANGE. HOWEVER STILL THINK HEAT ADVISORY CONDITIONS
LIKELY ON TUESDAY, AND THEN LESS SO WEDNESDAY AS RIDGE CONTINUES TO
WEAKEN.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/
A BROAD DEEP LAYER TROUGH WILL CONTINUE TO BUILD OVER THE NORTHEAST
AND MID ATLANTIC AND INTO THE SOUTHEAST U.S. STATES THROUGH FRIDAY,
THEN MOVING EASTWARD INTO THE ATLANTIC SATURDAY. THIS TROUGH MAY
ALLOW A SURFACE FRONT TO APPROACH FROM THE NORTH BY LATER FRIDAY,
THEN POTENTIALLY PUSH SOUTH OF THE REGION BY LATE SATURDAY.
INCREASING MOISTURE AND LOW LEVEL CONVERGENCE WITH THIS FRONT IS
EXPECTED TO BRING INCREASING CHANCES FOR CONVECTION THROUGH THE
PERIOD. WITH LOWER UPPER LEVEL HEIGHTS, THE THREAT FOR EXTREME HEAT
WARNINGS SHOULD BE LOWER, BUT STILL CANNOT RULE OUT HEAT ADVISORY
CONDITIONS DURING THIS PERIOD.
AVIATION /00Z MONDAY THROUGH FRIDAY/
28/00Z TAFS:
KCHS/KJZI/KSAV: WITH THE UPPER-LEVEL RIDGING OVERHEAD AND MID-
LEVEL SUBSIDENCE, VFR SHOULD REMAIN THROUGH AT LEAST MIDDAY
MONDAY. ISOLATED TO SCATTERED THUNDERSTORMS ENTER THE FORECAST
LATER MONDAY AFTERNOON, BUT WITH LIMITED COVERAGE AND TIMING
UNCERTAINTY, HAVE LEFT ANY AVIATION IMPACTS OUT OF THE TAFS FOR
THE TIME BEING.
EXTENDED AVIATION FORECAST: GENERALLY VFR CONDITIONS WITH BRIEF
FLIGHT RESTRICTIONS BECOMING MORE LIKELY THROUGH THE PERIOD AS
CHANCES FOR AFTERNOON CONVECTION INCREASE DUE TO INCREASING DEEP
LAYER MOISTURE AND THE POTENTIAL FOR A SURFACE FRONT TO IMPACT THE
AREA, ESPECIALLY LATER IN THE WEEK ON THURSDAY AND FRIDAY.
MARINE
LIGHT TO MODERATE S TO SW WINDS PREVAIL OVERNIGHT. SEAS REMAIN
MINIMAL, RANGING FROM 1 TO 2 FT OVERNIGHT. OVERALL, ABOUT AS
FAIR AS BOATING CONDITIONS GET.
MONDAY THROUGH FRIDAY: NO MARINE HAZARDS ARE EXPECTED THROUGH
THE PERIOD. A DEEP LAYER, ALTHOUGH WEAKENING THROUGH THE PERIOD,
WILL GENERALLY STRETCH FROM SOUTHEAST OF THE WATERS TO THE WEST
OVER THE GULF COAST STATES. THIS WILL MAINTAIN GENERALLY
SOUTHERLY WINDS OF 15 KNOTS OR LESS WITH ONSHORE FLOW/SEABREEZE
EACH AFTERNOON THROUGH AT LEAST THURSDAY. SEAS 2 TO 3 FEET. BY
LATER FRIDAY, A COLD FRONT MAY APPROACH FROM THE NORTH, WHICH
COULD VEER WINDS TO MORE SOUTHWEST.
CLIMATE
RECORD HIGH TEMPERATURES:
JULY 28:
KCHS: 101/1949
KCXM: 100/1936
KSAV: 102/1949
RECORD HIGH MINIMUM TEMPERATURES:
JULY 27:
KCHS: 80/2014
KSAV: 80/1885
JULY 28:
KCHS: 80/2016
KCXM: 83/1999
KSAV: 81/1878
JULY 29:
KCHS: 80/2016
KSAV: 82/1878
JULY 30:
KCHS: 81/2016
KCXM: 83/2016
KSAV: 81/1878
JULY 31:
KCHS: 80/2022
KCXM: 84/2016
KSAV: 80/2010
AUGUST 1:
KCHS: 81/1999
KSAV: 79/2020
AUGUST 2:
KCHS: 79/2022
CHS WATCHES/WARNINGS/ADVISORIES
GA...HEAT ADVISORY UNTIL 8 PM EDT MONDAY FOR GAZ087-088-099>101-
114>116-137-138-140.
EXTREME HEAT WARNING UNTIL 8 PM EDT MONDAY FOR GAZ117>119-139-
141.
SC...HEAT ADVISORY UNTIL 8 PM EDT MONDAY FOR SCZ040-042.
EXTREME HEAT WARNING UNTIL 8 PM EDT MONDAY FOR SCZ043>045-
047>052.
MARINE...NONE.
NEAR TERM...CEB/DENNIS
SHORT TERM...RFM
LONG TERM...RFM
AVIATION...CEB/RFM
MARINE...DENNIS/RFM
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