931  
FXUS62 KCHS 261208  
AFDCHS  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHARLESTON SC  
708 AM EST TUE JAN 26 2021  
   
SYNOPSIS
 
 
A STORM SYSTEM WILL IMPACT THE REGION TODAY INTO WEDNESDAY,  
BEFORE A STRONG COLD FRONT PUSHES OFFSHORE WEDNESDAY NIGHT.  
HIGH PRESSURE WILL RETURN LATE WEEK, FOLLOWED BY ANOTHER COLD  
FRONT EARLY NEXT WEEK.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
AS OF 7 AM: IR SATELLITE INDICATES STRATUS INCREASING FROM THE  
WEST ACROSS THE FORECAST AREA. ALSO, A THIN AREA OF SEA FOG WAS  
EVIDENT ALONG THE SC COAST. THE FORECAST UPDATE WILL FEATURE  
FASTER ARRIVAL OF THE CLOUD COVER AND WILL CONTINUE A MENTION OF  
PATCHY SEA FOG. OTHERWISE, TEMPERATURES WILL BEGIN THE DAY IN  
THE 60S, STEADILY WARMING THROUGH EARLY THIS AFTERNOON.  
 
AS OF 4 AM: LATEST IR SATELLITE DETECTED A LARGE SHIELD OF STRATUS  
ADVANCING NE ACROSS GA. BASED ON SATELLITE TRENDS, THE LEADING EDGE  
OF THE STRATUS SHOULD LIFT NORTH OF THE FORECAST AREA AROUND  
DAYBREAK. CLOUD COVER IS FORECAST TO REMAIN MOSTLY CLOUDY TO CLOUDY  
FOR THE REST OF THE DAY. TEMPERATURES ACROSS THE FORECAST AREA WILL  
BEGIN THE DAY IN THE LOWER 60S. THE LOW LEVEL THERMAL PROFILES  
SHOULD REMAIN VERY MILD AS RETURN FLOW STRENGTHENS AHEAD OF AN  
APPROACHING COLD FRONT. HIGH TEMPERATURES ARE EXPECTED TO RANGE  
WITHIN A DEGREE OR TWO OF VALUES REACHED YESTERDAY, GENERALLY UPPER  
70S ACROSS GA AND MID 70S ACROSS THE SC LOWCOUNTRY. SEE CLIMATE  
SECTION BELOW.  
 
NEAR TERM GUIDANCE INDICATES THAT THE SFC COLD FRONT WILL APPROACH  
FROM THE WEST THIS EVENING, THEN BECOMING STATIONARY OVER THE CWA  
TONIGHT. A PRE-FRONTAL BAND OF CONVECTION SHOULD GRADUALLY WEAKEN AS  
IT PUSHES EAST ACROSS GA/SC THIS MORNING. FADING SHOWERS MAY ARRIVE  
OVER THE INLAND COUNTIES DURING THE DAYLIGHT HOURS THIS MORNING,  
COVERAGE REMAINING ISOLATED TO SCATTERED. THIS EVENING, A AMPLIFIED  
H5 TROUGH WILL RIPPLE EAST OVER THE SOUTHERN PLAINS. AT THE SFC, LOW  
PRESSURE IS FORECAST TO ORGANIZE OVER THE DEEP SOUTH, TRACKING ENE  
ALONG THE STATIONARY FRONT. AS THE LOW DEVELOPS AND APPROACHES, A  
BAND OF FRONTOGENESIS WILL DEVELOP AND ALONG AND NORTH OF THE  
STATIONARY FRONT. IN ADDITION, A BAND OF WEAK SBCAPE WILL LINGER  
NEAR THE FRONT, WITH WEAK INSTABILITY PRESENT ACROSS SE GA AND THE  
SC LOWCOUNTRY. HIGH RESOLUTION GUIDANCE SHOWS CLUSTERS OF SHOWERS  
AND THUNDERSTORMS ARRIVING ACROSS SE GA THIS EVENING, ADVANCING  
ACROSS THE LOWCOUNTRY DURING THE OVERNIGHT HOURS. USING THE  
PLACEMENT AND TIMING OF THE SIMULATED REFLECTIVITY, I WILL SPREAD  
CATEGORICAL POPS ALONG AND WEST OF THE I-95 CORRIDOR TONIGHT.  
TEMPERATURES WILL WET-BULB DOWN TO THE LOW TO MID 60S LATE  
TONIGHT.  
 

 
   
SHORT TERM /WEDNESDAY THROUGH FRIDAY/
 
 
A STALLED COLD FRONT WILL BE POSITIONED OVER OR NEAR THE AREA AT THE  
START OF THE PERIOD WEDNESDAY. A WAVE OF LOW PRESSURE IS EXPECTED TO  
TRACK ALONG THE BOUNDARY THROUGH THE DAY AND EVENTUALLY OFF THE  
COAST WEDNESDAY EVENING. AMPLE LIFT AND MOISTURE WILL SUPPORT  
WIDESPREAD SHOWERS AND PERHAPS SOME EMBEDDED THUNDERSTORMS, ALTHOUGH  
INSTABILITY IS QUITE MARGINAL. AN ADDITIONAL 0.50 INCH OF RAINFALL  
IS FORECAST, WITH LOCALLY HIGHER AMOUNTS POSSIBLE. THERE WILL LIKELY  
BE A DECENT TEMPERATURE GRADIENT AS THE FRONT WAVERS IN THE  
VICINITY. CURRENT FORECAST FEATURES HIGHS RANGING FROM LOW 60S  
ACROSS THE NORTHERN ZONES TO AROUND 70/LOW 70S CLOSER TO THE  
ALTAMAHA.  
 
A TRAILING COLD FRONT WILL PUSH OFFSHORE WEDNESDAY NIGHT, WITH  
MOISTURE STRIPPING OUT QUICKLY AND RAIN COMING TO AN END. MOST  
PRECIPITATION SHOULD HAVE EXITED THE AREA BY MIDNIGHT. INCREASING  
COLD AIR ADVECTION WILL BRING TEMPERATURES DOWN TO THE UPPER 30S TO  
LOW 40S, ALTHOUGH BREEZY NORTHWEST WINDS BEHIND THE FRONT WILL MAKE  
IT FEEL A BIT COLDER.  
 
COOL AND DRY HIGH PRESSURE WILL EXPAND INTO THE REGION ON THURSDAY  
AND WILL PERSIST THROUGH FRIDAY. ALOFT, THE AREA WILL REMAIN UNDER  
NORTHWEST FLOW IN BETWEEN RIDGING BUILDING OVER THE CENTRAL AND  
SOUTHERN PLAINS AND TROUGHING TO THE EAST. QUIET WEATHER CONDITIONS  
ARE EXPECTED, ALTHOUGH WINDS WILL REMAIN A BIT GUSTY ON THURSDAY  
BEFORE THE PRESSURE GRADIENT RELAXES. DESPITE CLEAR SKIES,  
TEMPERATURES WILL REMAIN BELOW NORMAL. HIGHS BOTH DAYS WILL TOP OUT  
IN THE LOW TO MID 50S. GOOD RADIATIONAL COOLING CONDITIONS THURSDAY  
NIGHT WILL ALLOW LOWS TO DROP BELOW FREEZING ACROSS MOST LOCATIONS  
INLAND OF THE COAST.  
 
LAKE WINDS: STRONG COLD AIR ADVECTION BEHIND A DEPARTING COLD FRONT  
WILL PROMOTE GOOD MIXING PROFILES OVER LAKE MOULTRIE WEDNESDAY NIGHT  
INTO THURSDAY. WIND GUSTS IN EXCESS OF 25 KNOTS ARE POSSIBLE, AND A  
LAKE WIND ADVISORY WILL LIKELY BE NEEDED.  
 

 
   
LONG TERM /FRIDAY NIGHT THROUGH MONDAY/
 
 
HIGH PRESSURE WILL PREVAIL ON SATURDAY, ALLOWING QUIET AND DRY  
WEATHER TO CONTINUE. AN AMPLIFYING MID LEVEL TROUGH AND ASSOCIATED  
SURFACE LOW WILL THEN MOVE INTO THE REGION EARLY NEXT WEEK. WHILE  
THERE ARE STILL TIMING DISCREPANCIES BETWEEN MODELS, A COLD FRONT  
WILL EVENTUALLY PASS THROUGH, BRINGING THE NEXT CHANCE OF RAIN TO  
THE AREA. TEMPERATURES WILL BE NEAR TO ABOVE NORMAL THROUGH THE  
PERIOD.  
 

 
   
AVIATION /12Z TUESDAY THROUGH SATURDAY/
 
 
12Z KCHS UPPER AIR SOUNDING OBSERVED SW WINDS AT 40 KTS AT 1KFT  
AND SW AND 40 KTS AT 2 KFT. A COLD FRONT WILL APPROACH FROM THE  
WEST THIS MORNING. AS THE FRONT APPROACHES, LLVL WINDS WILL  
LINGER AROUND 40 KTS ACROSS THE SC LOWCOUNTRY THROUGH MOST OF  
THE MORNING. LLWS IS EXPECTED OVER KCHS BETWEEN UNTIL 13Z, THEN  
SFC WIND GUSTS SHOULD DEVELOP AND END LLWS. PRIOR TO THE 12Z  
TAFS, IR SATELLITE INDICATED IFR/MVFR CEILINGS APPROACHING BOTH  
TERMINALS. BASED ON SATELLITE TRENDS, I WILL INDICATE PERIODS OF  
LOW CEILINGS UNTIL MID-DAY. IN ADDITION, SW WINDS MAY GUSTS TO  
AROUND 20 KTS THIS AFTERNOON, ESPECIALLY AT KCHS. THE SFC COLD  
FRONT WILL SLOW AND BECOME STATIONARY OVER THE FORECAST AREA  
THIS EVENING. LOW PRESSURE WILL DEVELOP OVER THE DEEP SOUTH,  
TRACKING NE ALONG THE STATIONARY FRONT. A BAND OF SCATTERED TO  
NUMEROUS SHOWERS AND THUNDERSTORMS IS TIME TO REACH KSAV THIS  
EVENING. CEILINGS SHOULD CONTINUE TO LOWER THROUGH THE EVENING  
AND OVERNIGHT, REACHING IFR BY LATE THIS EVENING AT BOTH  
TERMINALS. LOW CEILINGS AND CONVECTION WILL REMAIN THROUGH THE  
REST OF THE 12Z TAFS.  
 
EXTENDED AVIATION OUTLOOK: FLIGHT RESTRICTIONS LIKELY IN LOW CLOUDS  
AND MODERATE RAIN THROUGH WEDNESDAY EVENING. GUSTY WINDS EXPECTED  
WEDNESDAY NIGHT INTO THURSDAY BEHIND A STRONG COLD FRONT.  
 

 
   
MARINE
 
 
TODAY AND TONIGHT: A COLD FRONT WILL REMAIN WEST OF THE MARINE ZONES  
THROUGH TODAY AND TONIGHT. AS A RESULT, WINDS WILL REMAIN OUT OF THE  
SW THROUGH NEAR TERM. WIND GUSTS COULD APPROACH SMALL CRAFT ADVISORY  
LEVELS ACROSS THE CHARLESTON COUNTY WATERS THIS AFTERNOON.  
OTHERWISE, SW WINDS COULD GUSTS AROUND 20 KTS THROUGH THE DAYLIGHT  
HOURS, SETTLING TO 10-15 KTS TONIGHT. IN ADDITION, PATCHY SEA FOG  
COULD DEVELOP FROM TIME TO TIME NEAR THE COAST TODAY. ROUNDS OF  
THUNDERSTORMS ARE FORECAST TO TRACK OVER THE NEARSHORE WATERS  
TONIGHT, ESPECIALLY OFF THE SC COAST.  
 
WEDNESDAY THROUGH SUNDAY: LOW PRESSURE WILL PASS OVER THE REGION ON  
WEDNESDAY, FOLLOWED BY A STRONG COLD FRONT WEDNESDAY EVENING/NIGHT.  
WINDS AND SEAS WILL DETERIORATE IN ITS WAKE, AND AT THE LEAST, SMALL  
CRAFT ADVISORIES WILL BE NEEDED FOR ALL WATERS. THE WORST CONDITIONS  
LOOK TO OCCUR BETWEEN MIDNIGHT AND DAYBREAK THURSDAY, WHEN GALE  
FORCE GUSTS WILL BE POSSIBLE, PARTICULARLY OVER THE CHARLESTON  
COUNTY NEARSHORE WATERS AND OUTER GEORGIA WATERS. GALE  
WATCHES/WARNINGS COULD EVENTUALLY BE NEEDED. THERE WILL BE A GRADUAL  
IMPROVEMENT ON THURSDAY AS THE PRESSURE GRADIENT RELAXES. NO  
ADDITIONAL CONCERNS ARE ANTICIPATED THROUGH SATURDAY AS HIGH  
PRESSURE EXPANDS OVER THE REGION. A COLD FRONT WILL APPROACH FROM  
THE WEST ON SUNDAY AND WILL BRING INCREASING WINDS AND SEAS.  
 

 
   
CLIMATE
 
 
RECORD HIGHS FOR 26 JANUARY:  
KCHS: 80/1949  
KCXM: 79/1949  
KSAV: 81/1974 AND 1962  
 
RECORD HIGH MIN FOR 26 JANUARY:  
KCHS: 59/1949  
KCXM: 60/1974  
KSAV: 62/1974  
 

 
   
CHS WATCHES/WARNINGS/ADVISORIES
 
 
GA...NONE.  
SC...NONE.  
MARINE...NONE.  
 

 
 

 
 
NEAR TERM...NED  
SHORT TERM...ETM  
LONG TERM...ETM  
AVIATION...NED  
MARINE...NED  
CLIMATE...  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab SC Page
The Nexlab GA Page Main Text Page