824
FXUS62 KCHS 220544
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
144 AM EDT MON JUN 22 2026
WHAT HAS CHANGED
ALL SECTIONS AND KEY MESSAGES HAVE BEEN UPDATED.
KEY MESSAGES
- 1) A FAIRLY TYPICAL SUMMERTIME PATTERN IS FORECAST WITH DAILY
SHOWER AND THUNDERSTORM CHANCES THROUGH THE WEEKEND.
DISCUSSION
KEY MESSAGE 1: A FAIRLY TYPICAL SUMMERTIME PATTERN IS FORECAST
WITH DAILY SHOWER AND THUNDERSTORM CHANCES THROUGH THE WEEKEND.
THROUGH TONIGHT, THE SYNOPTIC PATTERN HAS CHANGED LITTLE SINCE
SUNDAY WITH THE REGION WILL POSITIONED ALONG THE WESTERN FLANKS
OF ATLANTIC HIGH PRESSURE CENTERED WELL OFFSHORE. THE FLOW ALOFT
WILL BE BIT MORE WESTERLY COMPARED TO 24 HOURS AGO WHICH WILL
TEND TO KEEP THE SEA BREEZE PINNED TO THE IMMEDIATE COAST FOR
MUCH OF THE DAY WITH IT POSSIBLY BEGINNING A EXTREMELY SLOW
INLAND TREK CLOSER TO LATE AFTERNOON, ESPECIALLY ALONG THE LOWER
SOUTH CAROLINA COAST. WARM AND MOIST CONDITIONS WILL REMAIN
PLACE TODAY WITH DEWPOINTS LIKELY TO HOLD IN THE LOWER-MID 70S
EXCEPT OVER PARTS OF THE CHARLESTON TRI-COUNTY INTO COLLETON
COUNTY WHERE THE MOISTURE DEPTH IS A BIT MORE SHALLOW AND MORE
VIGOROUS VERTICAL MIXING COULD ALLOW DEWPOINTS TO MIX OUT IN
THE UPPER 60S IN SPOTS. HIGHS ARE POISED TO WARM INTO THE LOWER-
MID 90S FOR MANY SPOTS WITH HEAT INDICES PEAKING IN THE 100-106F
RANGE WHICH IS BELOW THE LOCAL HEAT ADVISORY CRITERIA OF 108F.
SIMILAR TO YESTERDAY, THE AIRMASS WILL REMAIN SUPPORTIVE OF
PULSE CONVECTION IN THE ABSENCE OF ANY MEANINGFUL SYNOPTIC
FORCING MECHANISMS. THE CONVECTIVE PATTERN WILL LIKELY BE
AUGMENTED ON THE MESOSCALE AT TIMES WITH AN ISOLATED STRONG OR
SEVERE TSTM BECOMING POSSIBLE WHERE UPDRAFTS CAN BE LOCALLY
ENHANCED BY BOUNDARY COLLISIONS NEAR THE SEA BREEZE OR OTHER
CONVECTIVE OUTFLOWS. WIND GUSTS 40-60 MPH, FREQUENT CLOUD-TO-
GROUND LIGHTNING AND LOCALLY HEAVY RAINFALL WILL BE THE PRIMARY
HAZARDS. POPS 20-30% LOOK REASONABLE FOR MOST AREAS THIS
AFTERNOON WITH CONVECTION WINDING DOWN DURING THE EVENING HOURS.
WILL HAVE TO WATCH FOR SOME NOCTURNAL CONVECTION APPROACHING
INTERIOR SOUTHEAST GEORGIA FROM THE WEST CLOSER TO THE MIDNIGHT,
BUT MOST OF THIS SHOULD DISSIPATE PRIOR TO REACHING THIS FAR
EAST AS DIURNAL INSTABILITY WANES.
A SOUTHWESTERLY FLOW AHEAD OF APPROACHING COLD FRONT WILL
LIKELY KEEP THE BOUNDARY WELL MIXED FOR MANY AREAS OVERNIGHT.
THIS WILL TEND TO KEEP TEMPERATURES UP THROUGH SUNRISE WITH LOWS
LIKELY ONLY BOTTOMING OUT IN THE LOWER-MID 70S WEST OF I-95
WITH UPPER 70S/NEAR 80 ELSEWHERE. THE RECORD HIGH MINIMUMS AT
ALL THREE CLIMATE SITES COULD BE CHALLENGED, ASSUMING CONVECTION
DURING THE DAY TUESDAY DOES NOT DRIVE TEMPERATURES BELOW RECORD
LEVELS PRIOR TO 1 AM WEDNESDAY. SEE THE CLIMATE SECTION BELOW
FOR ADDITIONAL DETAILS.
GUIDANCE SUGGESTS A WEAK COLD FRONT WILL MOVE TOWARD THE CAROLINA
COAST AND ACROSS CENTRAL GEORGIA TUESDAY AND THEN STALL, REMAINING
NEARLY THROUGH THE END OF THE WEEK. ISOLATED TO SCATTERED SHOWERS
AND THUNDERSTORMS ARE POSSIBLE TUESDAY, OWING TO THE FRONT IN THE
VICINITY. BUT DEEP WESTERLY FLOW ADVECTING DRIER AIR INTO THE AREA
WILL LIMIT CONVECTION. THEN A SEASONABLE COMBINATION OF OFFSHORE
RIDGING/INLAND TROUGHING REESTABLISHES THROUGH THE DAY WEDNESDAY AND
PERSISTS INTO THE WEEKEND, WITH WEAK SUBSIDENCE ALOFT MAINTAINING
MAINLY ISOLATED TO SCATTERED DIURNAL DAILY CONVECTION. A FEW
STRONGER STORMS ARE POSSIBLE EACH AFTERNOON, BUT THERE IS NO
APPARENT SIGNIFICANT SEVERE THREAT AT THIS TIME.
AVIATION /06Z MONDAY THROUGH FRIDAY/
22/06Z TAF DISCUSSION:
KCHS/KJZI/KSAV: VFR FOR MUCH OF THE PERIOD. AN AREA OF EXPANDING
MVFR CIGS OVER INTERIOR SOUTHEAST GEORGIA COULD MAKE A RUN FOR
MAINLY KCHS AND KSAV PRIOR TO DAYBREAK. TEMPO GROUPS FOR MVFR
CIGS WERE INTRODUCED 09-12Z AT THOSE TERMINALS FOR NOW.
AMENDMENTS MAY BE NEEDED IF THE RISK FOR PREVAILING MVFR CIGS
BECOME MORE APPARENT. ISOLATED SHOWER/TSTMS ARE EXPECTED THIS
AFTERNOON. IMPACT PROBABILITIES ARE TOO LOW TO JUSTIFY A MENTION
OF TSRA AT ANY OF THE TERMINALS AT THIS TIME. THE NEED TO
MENTION TSRA WILL BE REEVALUATED FOR THE 12Z TAF CYCLE.
EXTENDED AVIATION OUTLOOK: BRIEF FLIGHT RESTRICTIONS ARE POSSIBLE
WITH MAINLY AFTERNOON SHOWERS AND THUNDERSTORMS.
MARINE
TODAY: A BROAD SOUTHERLY FLOW REGIME WILL PERSIST ACROSS THE
WATERS TODAY AS HIGH PRESSURE HOLDS WELL OFFSHORE. A WESTERLY
FLOW ALOFT WILL DELAY THE DEVELOPMENT OF THE SEA BREEZE, BUT
ONE SHOULD EVENTUALLY DEVELOP, BUT REMAINED PINNED TO/NEAR THE
COAST UNTIL LATE. WEST WINDS 10-15 KT WILL BACK TO THE SOUTHWEST
LATER IN THE DAY, BUT INCREASE TO 15-20 KT WITH GUSTS TO 25 KT
ACROSS THE SOUTH SANTEE-EDISTO BEACH NEARSHORE AND OFFSHORE LEGS
LATER THIS AFTERNOON. SEAS WILL BUILD TO 2-4 FT.
TONIGHT: THE PATTERN LOOKS TO FAVOR A CLASSIC SUMMER NOCTURNAL
SURGE TONIGHT AS HIGH PRESSURE REMAINS WELL OFFSHORE AND A COLD
FRONT APPROACHES FROM THE NORTHWEST. THE HIGHEST OVERNIGHT WINDS
LOOK TO CENTER ACROSS THE SOUTH CAROLINA NEARSHORE AND OFFSHORE
WATERS WITH THE RISK FOR REACHING FREQUENT GUSTS 25-30 KT
PEAKING OVER THE SOUTH SANTEE-EDISTO BEACH NEARSHORE AND
OFFSHORE LEGS. HREF PROBABILITIES FOR FREQUENT GUSTS >25 KT
SURGE AS HIGH AS 30-65% BY 4 PM THIS AFTERNOON ACROSS THESE
WATERS AND PEAK 70-100% A FEW HOURS PRIOR TO DAYBREAK TUESDAY.
GIVEN THESE TRENDS AND THE PATTERN SETUP, A SMALL CRAFT ADVISORY
HAS BEEN ISSUED FOR THE SOUTH SANTEE-EDISTO BEACH NEARSHORE LEG
FROM 4 PM UNTIL 6 AM TUESDAY. THE ADVISORY MAY NEED TO BE
EXPANDED SOUTH INTO THE EDISTO BEACH-SAVANNAH NEARSHORE LEG
LATER TODAY, BUT THE SITUATION LOOKS A BIT TOO MARGINAL TO HOIST
AN ADVISORY AT THIS TIME. ALTHOUGH ADVISORY THRESHOLDS WILL BE
MET OVER BOTH SOUTH CAROLINA OFFSHORE ZONES, SMALL CRAFT
ADVISORIES ARE NOT CURRENTLY BEING ISSUED FOR THESE WATERS.
SEAS WILL AVERAGE 2-4 FT, EXCEPT BUILD TO 4-5 FT OVER THE SOUTH
SANTEE-EDISTO BEACH OFFSHORE LEG AFTER MIDNIGHT.
TUESDAY THROUGH SATURDAY: A WEAK COLD FRONT WILL APPROACH THE
CAROLINA COAST TUESDAY AND STALL THROUGH THE END OF THE WEEK. A
PINCHED PRESSURE GRADIENT FROM OFFSHORE HIGH PRESSURE AND LOW
PRESSURE IN THE MID ATLANTIC WILL RESULT IN GUSTS APPROACHING 25
KNOTS AT TIMES TUESDAY, ESPECIALLY ACROSS THE CHARLESTON COUNTY
NEARSHORE WATERS. A BRIEF SMALL CRAFT ADVISORY COULD BE NEEDED,
MAINLY BETWEEN THE AFTERNOON AND EVENING HOURS. THEREAFTER, THE
PRESSURE GRADIENT WILL RELAX AS HIGH PRESSURE GRADUALLY
REBUILDS OVER LAND. THERE ARE NO ADDITIONAL MARINE CONCERNS
THROUGH THE REMAINDER OF THE PERIOD.
CLIMATE
RECORD HIGH MINIMUM TEMPERATURES:
JUNE 23:
KCHS: 78/2024
KCXM: 82/1998
KSAV: 77/2017
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM
EDT TUESDAY FOR AMZ360.
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