254  
FXUS62 KCHS 181454  
AFDCHS  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHARLESTON SC  
954 AM EST MON NOV 18 2024  
   
SYNOPSIS
 
 
HIGH PRESSURE WILL PREVAIL UNTIL A STRONG COLD FRONT MOVES  
THROUGH MID WEEK. CANADIAN HIGH PRESSURE WILL BUILD ACROSS THE  
AREA THURSDAY INTO SUNDAY.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
TODAY: THE MID AND UPPER LEVEL RIDGING REMAINS ANCHORED OVER THE  
AREA, AS A DEEP CYCLONE ALOFT IN THE OKLAHOMA AND TEXAS  
PANHANDLES THIS MORNING, LIFTS INTO THE CENTRAL PLAINS THIS  
AFTERNOON. AT THE SURFACE, HIGH PRESSURE DIRECTLY OVERHEAD  
PULLS INTO THE OCEAN THIS AFTERNOON. THE RESULT IS FOR A DEEP  
WESTERLY FLOW THROUGH THE VERTICAL, AND COMBINED WITH A SLIGHT  
RISE IN THICKNESS FROM YESTERDAY, AND SUFFICIENT INSOLATION,  
HIGHS WILL REACH THE MIDDLE 70S JUST ABOUT EVERYWHERE. A FEW  
UPPER 70S COULD OCCUR NEAR THE ALTAMAHA RIVER, WHILE WEAK SEA  
BREEZE INFLUENCES WILL HOLD COASTAL SECTIONS FROM BEAUFORT  
COUNTY NORTH IN THE MID AND UPPER 60S. ONE ITEM OF NOTE IS IN  
REGARDS TO SKY COVER. A BAND OF STRATOCUMULUS WILL IMPACT  
MCINTOSH COUNTY THROUGH MIDDAY, CUTTING DOWN ON THEIR CLIMB OF  
TEMPERATURES. WITH THE ASSUMPTION THAT THESE CLOUDS WILL BREAK  
APART THIS AFTERNOON, WE'LL LEAVE HIGH TEMPERATURES AS BEFORE  
OVER THAT COUNTY, AND ADJUST IF NECESSARY WITH THE NEXT UPDATE.  
 
TONIGHT: HIGH PRESSURE WILL REMAIN ANCHORED OVER THE SOUTHWEST  
ATLANTIC AS A COLD FRONT MOVES INTO THE LOWER MISSISSIPPI VALLEY  
LATE. MODEL CONSENSUS IS THAT ANY PRECIPITATION AHEAD OF THE  
FRONT WILL REMAIN DISPLACED WELL TO OUR WEST THROUGH SUNRISE,  
KEEPING THE REGION DRY THROUGH THE OVERNIGHT. HIGH CLOUDS WILL  
START TO INCREASE FROM THE WEST LATE, BUT OVERALL WE SHOULD SEE  
MOSTLY CLEAR SKIES. LOW TEMPERATURES WILL CONTINUE AN UPWARD  
TREND FROM THE PREVIOUS FEW NIGHTS, WITH UPPER 40S AND LOW 50S  
EXPECTED AWAY FROM THE IMMEDIATE COAST.  
 

 
   
SHORT TERM /TUESDAY THROUGH THURSDAY/
 
 
SHORTWAVE ENERGY WILL PASS ACROSS THE REGION WELL AHEAD OF THE  
MAIN TROUGH AXIS TUESDAY INTO TUESDAY NIGHT. AT THE SURFACE,  
OFFSHORE HIGH PRESSURE WILL CONTINUE TO WEAKEN IN ADVANCE OF A  
COLD FRONT AND POSSIBLY A WEAK WAVE OF LOW PRESSURE PASSING  
ALONG THE GULF COAST STATES. MOST OF THE DAY WILL BE DRY THEN  
RAIN CHANCES WILL INCREASE FROM THE WEST LATE AND INTO THE  
OVERNIGHT. IT IS POSSIBLE THAT THE BULK OF ACTIVITY STAYS SOUTH  
OF THE AREA OR CLIPPING OUR FAR SOUTHEAST GEORGIA ZONES. THIS IS  
WHERE WE HAVE OUR HIGHEST POPS, GENERALLY PEAKING AROUND 50%.  
LESSER COVERAGE AND INTENSITY EXPECTED FURTHER NORTH.  
TEMPERATURES WILL AVERAGE IN THE MID 70S, WITH SOME SPOTS IN THE  
UPPER 70S. LOWS WILL BE MILD WITH ABUNDANT CLOUD COVER IN  
PLACE, ONLY FALLING TO AROUND 60/LOW 60S.  
 
AFOREMENTIONED COLD FRONT WILL SWEEP THROUGH THE AREA LATER  
WEDNESDAY. SHOWERS COULD LINGER THROUGH THE MORNING, THEN WILL  
DECREASE DURING THE LATTER HALF OF THE DAY AS DRIER AIR MOVES IN  
FROM THE WEST. LAND AREAS SHOULD BY RAIN-FREE BY WEDNESDAY  
NIGHT. ONE LAST DAY OF SEASONALLY WARM TEMPERATURES IN THE MID  
70S. LOWS WILL BE IN THE 40S.  
 
DEEP UPPER TROUGH WILL REMAIN OVER THE EASTERN CONUS ON  
THURSDAY, WHILE SURFACE LOW PRESSURE SPINS OVER THE NORTHEAST.  
TIGHT PRESSURE GRADIENT WILL BE IN PLACE OVER THE LOCAL AREA  
LEADING TO GUSTY WEST WINDS. OTHERWISE, TEMPERATURES WILL BE  
NOTABLY COOLER DESPITE SUNNY SKIES. HIGHS WILL ONLY RISE TO THE  
UPPER 50S TO LOWER 60S.  
 
LAKE WINDS: GUSTY WEST WINDS ARE EXPECTED TO DEVELOP OVER LAKE  
MOULTRIE WEDNESDAY NIGHT INTO THURSDAY BEHIND A COLD FRONT. A  
LAKE WIND ADVISORY APPEARS LIKELY.  
 

 
   
LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/
 
 
SURFACE LOW PRESSURE OVER THE NORTHEAST ON FRIDAY WILL FINALLY  
GIVE WAY, ALLOWING HIGH PRESSURE TO BUILD OVER THE AREA FOR THE  
WEEKEND. ALOFT, MID LEVEL TROUGH OVER THE EASTERN U.S. WILL ALSO  
EXIT WITH A RETURN TO ZONAL FLOW OR EVEN SUBTLE RIDGING LATE IN  
THE PERIOD. DRY WEATHER WILL PREVAIL. GUSTY WEST WINDS WILL  
LIKELY PERSIST INTO FRIDAY, POTENTIALLY MAINTAINING A LAKE WIND  
ADVISORY OVER LAKE MOULTRIE, BEFORE THE PRESSURE GRADIENT  
WEAKENS AND WINDS EASE. COOLER TEMPERATURES ARE EXPECTED THROUGH  
THE PERIOD. OVERNIGHT TEMPERATURES ARE FORECAST TO FALL INTO  
THE 30S OVER MANY INLAND LOCATIONS. WILL NEED TO MONITOR THE  
POTENTIAL FOR FROST, ESPECIALLY SATURDAY NIGHT.  
 

 
   
AVIATION /15Z MONDAY THROUGH FRIDAY/
 
 
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT KCHS, KJZI, AND KSAV  
THROUGH 12Z TUESDAY. SHALLOW GROUND FOG IS EXPECTED AT THE TAF  
SITES AROUND SUNRISE, BUT NO FLIGHT RESTRICTIONS ARE EXPECTED AT  
THIS TIME.  
 
EXTENDED AVIATION OUTLOOK: PREVAILING VFR. BRIEF FLIGHT  
RESTRICTIONS POSSIBLE IN SHOWERS TUESDAY NIGHT INTO WEDNESDAY IN  
ADVANCE OF A COLD FRONT. GUSTY WEST WINDS ARE EXPECTED THURSDAY  
AND FRIDAY.  
 

 
   
MARINE
 
 
TODAY AND TONIGHT: VERY QUIET CONDITIONS WILL CONTINUE FOR THE  
LOCAL WATERS. WINDS WILL BECOME A BIT MORE SOUTHWESTERLY THROUGH  
THE PERIOD, BUT SPEEDS ARE EXPECTED TO BE 10 KNOTS OR LESS.  
SEAS ARE FORECAST TO BE 1-2 FEET.  
 
TUESDAY THROUGH SATURDAY: NO MARINE CONCERNS THROUGH TUESDAY  
NIGHT. A STRONG COLD FRONT WILL MOVE THROUGH LATER WEDNESDAY  
WITH INCREASING WINDS AND SEAS IN ITS WAKE. SMALL CRAFT  
ADVISORIES ARE LIKELY FOR ALL WATERS, INCLUDING THE CHARLESTON  
HARBOR, BEGINNING WEDNESDAY NIGHT AND POTENTIALLY CONTINUING  
THROUGH FRIDAY. THERE REMAINS SOME RISK FOR GUSTS TO NEAR GALE  
FORCE OVER PORTIONS OF THE WATERS, ESPECIALLY THURSDAY NIGHT,  
BUT SEEMS PRETTY MARGINAL AND BRIEF AT THIS POINT. IMPROVEMENT  
IS EXPECTED ON SATURDAY AS THE PRESSURE GRADIENT EASES.  
 

 
   
TIDES/COASTAL FLOODING
 
 
TIDES WILL PEAK AROUND 7.28 FT MLLW IN CHARLESTON HARBOR, OR AT  
MINOR COASTAL FLOOD LEVELS, WHILE FORT PULASKI LOOKS LIKE AROUND  
9.25 FEET MLLW, WHICH IS SHORT OF OF ADVISORY CRITERIA.  
 
TIDES WILL BE CLOSE TO MINOR FLOODING LEVELS WITH THE TUESDAY  
MORNING HIGH TIDE ALONG THE CHARLESTON AND COLLETON COUNTY  
COASTS, BUT THE LATEST FORECAST KEEPS IT JUST SHY.  
 

 
   
CHS WATCHES/WARNINGS/ADVISORIES
 
 
GA...NONE.  
SC...COASTAL FLOOD ADVISORY UNTIL 11 AM EST THIS MORNING FOR SCZ049-  
050.  
MARINE...NONE.  
 

 
 

 
 
NEAR TERM...  
SHORT TERM...ETM  
LONG TERM...ETM  
AVIATION...BSH/ETM  
MARINE...  
 
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