111
FXUS62 KCHS 071138
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
738 AM EDT THU MAY 7 2026
WHAT HAS CHANGED
KEY MESSAGE 1 HAS BEEN UPDATED FOR RECENT TRENDS AND ISOLATED
SEVERE WEATHER POTENTIAL TODAY. THE AVIATION SECTION HAS BEEN
UPDATED FOR THE 12Z TAF ISSUANCE.
KEY MESSAGES
- 1) ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE TODAY.
- 2) UNSETTLED WEATHER RETURNS FRIDAY NIGHT AND LINGERS THROUGH EARLY
NEXT WEEK.
DISCUSSION
KEY MESSAGE 1: ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE TODAY.
A MOIST SOUTH/SOUTHWEST FLOW WILL PREVAIL ACROSS THE SOUTHEAST
UNITED STATES IN ADVANCE OF COLD FRONT APPROACHING THE REGION LATE
DAY, DRIVEN BY A LONGWAVE TROUGH ADVANCING ACROSS THE GREAT LAKES
REGION TOWARD THE MID-ATLANTIC/NORTHEAST COAST. PRIOR TO DAYBREAK,
INSTABILITY WILL REMAIN QUITE LOW, WHICH REMAINS EVIDENT ON RECENT
RADAR IMAGERY WITH SHOWERS AND THUNDERSTORMS IN A WEAKER STATE AHEAD
OF ENHANCED FORCING ARRIVING MID-LATE MORNING. GUIDANCE SUGGESTS
THIS ACTIVITY TO BE THE FIRST OF TWO CONVECTIVE WAVES ENTERING
SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA TODAY, LIKELY THE
WEAKER OF THE TWO WHILE THROUGH EARLY DAYLIGHT HOURS.
THE KEY TO ISOLATED SEVERE WEATHER TODAY WILL CONTINUE TO FOCUS ON
THE ABILITY OF THE ATMOSPHERE TO DESTABILIZE PRIOR TO A SECOND WAVE
OF CONVECTION ARRIVING MID-LATE MORNING INTO EARLY AFTERNOON. THE
MAIN ISSUE REVOLVES AROUND LIMITED INSTABILITY DURING TIMING OF
ENHANCED DEEP-LAYER SHEAR AND FORCING ASSOCIATED WITH LOW-LVL
JETTING WHILE A STRONG H25 JET CORE PASSES WELL INLAND AND NORTH OF
THE LOCAL AREA. THE LONGER MORNING CONVECTION OCCURS, THE LESS
LIKELY THE ATMOSPHERE RECOVERS FOR AN ISOLATED SEVERE WEATHER
SCENARIO LATE MORNING AND AFTERNOON. HOWEVER, HIRES GUIDANCE
MAINTAINS A SECOND WAVE OF CONVECTION PRIOR TO COLD FROPA, MAINLY IN
THE FORM OF SMALL THUNDERSTORM CLUSTERS THAT ARRIVE AT A TIME WHEN
INSTABILITY PEAKS ACROSS THE LOCAL AREA. SOME GUIDANCE PLACES AN
AXIS OF MODEST INSTABILITY (SBCAPE ~1500 J/KG) ACROSS SOUTHEAST
GEORGIA AND PERHAPS INTO COASTAL PARTS OF SOUTHERN SOUTHEAST SOUTH
CAROLINA THIS AFTERNOON WHERE A FEW BREAKS IN CLOUD COVER AND WARM
AIR ADVECTION ALLOW FOR SFC TEMPS TO REACH THE MID-UPPER 80S. SFC
TEMPS ARE LIKELY TO BECOME WARMEST NEAR THE I-95 CORRIDOR IN
SOUTHEAST GEORGIA, EVEN POSSIBLY REACHING 90 DEGREES BEFORE THE
ONSET OF ADDITIONAL SHOWER AND THUNDERSTORM ACTIVITY LATER TODAY.
THE COMBINATION OF DEEP MOISTURE (PWATS 2.0 INCHES/SFC DEWPTS LOWER
70S) AND 0-6 KM BULK SHEAR (~50 KT) SUPPORTS AN ISOLATED SEVERE
WEATHER THREAT, CONDITIONAL ON SFC HEATING/INSTABILITY REALIZED
PRIOR TO THE SECOND WAVE OF CONVECTION ARRIVING LATE MORNING INTO
EARLY AFTERNOON. MOSTLY UNIDIRECTIONAL WIND PROFILES DEPICTED ON
SOUNDINGS WITH MODEST DIRECTIONAL CHANGE IN H85-H5 CROSSOVER WINDS
ALONG WITH LOW-LVL LAPSE RATES AROUND 6.5-7 C/KM SUPPORT PRIMARILY A
DAMAGING WIND THREAT BY A FEW THUNDERSTORMS THAT BECOME
STRONG/SEVERE WITHIN CLUSTERS AND/OR PERHAPS SMALL LINEAR SEGMENTS.
HOWEVER, THERE REMAINS A NON-ZERO RISK FOR A BRIEF TORNADO ACROSS
SOUTHEAST GEORGIA (SOUTH OF I-16 AND CLOSER TO THE ALTAMAHA RIVER)
SHOULD AMPLE INSTABILITY DEVELOP PRIOR TO THE ONSET OF AFTERNOON
CONVECTION AHEAD OF A SEA BREEZE. THE BULK OF THUNDERSTORM ACTIVITY
SHOULD REMAIN SUB-SEVERE TODAY, BUT STILL CAPABLE OF PRODUCING BRIEF
MODERATE-HEAVY RAINS AND PERHAPS A MINOR FLOODING EPISODE WITHIN A
DEEP MOISTURE ENVIRONMENT, ESPECIALLY IF THE PROGRESSION OF THE
ARRIVING COLD FRONT SLOWS WHILE PASSING ACROSS THE AREA STARTING
LATE DAY/EARLY EVENING. THE STORM PREDICTION CENTER CONTINUES TO
PLACE A MARGINAL RISK (1/5) FOR SEVERE WEATHER ACROSS THE ENTIRE
AREA TODAY.
KEY MESSAGE 2: UNSETTLED WEATHER RETURNS FRIDAY NIGHT AND LINGERS
THROUGH EARLY NEXT WEEK.
DRY HIGH PRESSURE WILL BRIEFLY REBUILD ON FRIDAY, THEN THE FRONT
WILL LIFT BACK NORTH AND STALL OVER THE AREA FRIDAY NIGHT THROUGH
SUNDAY. A SERIES OF UPPER LEVEL SHORTWAVES WILL RIPPLE THROUGH THE
SOUTHEAST DURING THIS PERIOD. MEANWHILE, PWATS APPROACHING 1.8"
EXPECTED TO ADVECT INTO THE AREA SATURDAY THROUGH SUNDAY, PROVIDING
AMPLE MOISTURE FOR SHOWER DEVELOPMENT. POCKETS OF SURFACE-BASED
INSTABILITY WILL SUPPORT ISOLATED THUNDERSTORMS, PARTICULARLY DURING
THE AFTERNOON HOURS ACROSS COASTAL SOUTHEAST GA. TOTAL PRECIPITATION
FRIDAY NIGHT THROUGH SUNDAY EXPECTED TO RANGE FROM 0.75"-1.25",
THOUGH A FEW LOCATIONS COULD SEE AMOUNTS IN EXCESS OF 1.5". RAINFALL
AMOUNT AND INTENSITY NOT CURRENTLY EXPECTED TO RESULT IN A
SIGNIFICANT FLOODING THREAT.
A STRONG COLD FRONT WILL SWEEP THROUGH MONDAY AFTERNOON, BRINGING
NUMEROUS SHOWERS AND A FEW THUNDERSTORMS. GUIDANCE INDICATES THE
POTENTIAL FOR MODERATE SHEAR AND INSTABILITY PRECEDING THE FRONT, SO
AN ISOLATED SEVERE THUNDERSTORM WITH DAMAGING WINDS IS POSSIBLE.
AVIATION /12Z THURSDAY THROUGH MONDAY/
LIGHT TO MODERATE SHOWERS ARE EXPECTED AT ALL TERMINALS EARLY THIS
MORNING, WITH MVFR/IFR CONDITIONS POSSIBLE BETWEEN THE 14-18Z
TIMEFRAME AT CHS/JZI AND 12-16Z AT SAV DUE TO THUNDERSTORMS. GUSTY
WINDS UP TO 20-25 KT ARE ALSO POSSIBLE WITH SHOWER/THUNDERSTORM
ACTIVITY LATE MORNING AND AFTERNOON. PERIODS OF MVFR CIGS ARE LIKELY
AT ALL TERMINALS MID-LATE AFTERNOON INTO POSSIBLY EARLY EVENING,
PRIOR TO A COLD FRONT SHIFTING THROUGH THE REGION WITH DRY HIGH
PRESSURE BUILDING IN ITS WAKE. VFR CONDITIONS ARE THEN EXPECTED BY
LATE EVENING AND ARE LIKELY TO PERSIST THROUGH 12Z FRIDAY.
EXTENDED AVIATION OUTLOOK: OCCASIONAL FLIGHT RESTRICTIONS SATURDAY
THROUGH MONDAY AS A STALLED FRONT BRINGS SHOWERS AND THUNDERSTORMS.
MARINE
TODAY AND TONIGHT: A SOMEWHAT ENHANCED PRESSURE GRADIENT ACROSS
LOCAL WATERS WILL SLOWLY WEAKEN IN ADVANCE OF PRE-FRONTAL CONVECTION
LATE MORNING AND AFTERNOON. SOUTHERLY WINDS CONTINUE TO GUST UP TO
20-25 KT ACROSS NEARSHORE SOUTH CAROLINA WATERS AND ACROSS OFFSHORE
WATERS WITH SEAS AS LARGE AS 4-6 FT (LARGEST BEYOND 20 NM FROM
THE COAST ACROSS SOUTH CAROLINA WATERS). SMALL CRAFT ADVISORIES
REMAIN IN EFFECT FOR NEARSHORE SOUTH CAROLINA WATERS AND OFFSHORE
GEORGIA WATERS THROUGH 10 AM. A COLD FRONT ARRIVES ACROSS THE
AREA THIS EVENING, LIKELY PASSING OFFSHORE ACROSS ALL WATERS
OVERNIGHT. ALTHOUGH WINDS COULD BRIEFLY SURGE POST FROPA, COLD
AIR ADVECTION DOES NOT APPEAR STRONG ENOUGH TO SUPPORT WINDS
HIGHER THAN 20 KT ACROSS LOCAL WATERS.
A RELATIVELY STRONG NORTHERLY FLOW WILL DEVELOP MONDAY NIGHT INTO
TUESDAY BEHIND ANOTHER COLD FRONT AS HIGH PRESSURE BUILDS IN. SMALL
CRAFT ADVISORIES MAY BE NEEDED FOR MOST WATERS OUTSIDE CHARLESTON
HARBOR DUE TO FREQUENT 25 KT WIND GUSTS.
RIP CURRENTS: ENHANCED WINDS ALONG THE LOWER SOUTH CAROLINA COAST
COUPLED WITH BUILDING 2-4 FT SWELL SUPPORTS A MODERATE RISK FOR RIP
CURRENTS ALONG THE CHARLESTON COUNTY BEACHES FOR TODAY.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EDT THIS MORNING FOR AMZ360-
362-384.
DPB/JRL
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