860
FXUS62 KCHS 210916
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
416 AM EST THU NOV 21 2024
SYNOPSIS
CANADIAN HIGH PRESSURE WILL BUILD ACROSS THE AREA TODAY AND
WILL REMAIN THE PRIMARY FEATURE THROUGH EARLY NEXT WEEK. A COLD
FRONT COULD APPROACH THE AREA TOWARDS THE MIDDLE OF NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
UNTIL SUNRISE: STRONG CAA PERSISTS ACROSS THE REGION, WITH
TEMPERATURES CONTINUING TO DROP OVER THE NEXT COUPLE OF HOURS.
SKIES REMAIN CLEAR, AND DRY CONDITIONS ARE EXPECTED THROUGH THE
NIGHT. WINDS SHOULD DIMINISH A LITTLE OVER THE NEXT 1-2 HOURS
INLAND AND THEN PICK UP AFTER SUNRISE. GUSTY NORTHWEST WINDS
WILL MAKE IT FEEL EVEN COOLER BY DAYBREAK THURSDAY WITH WIND
CHILLS DROPPING INTO THE UPPER 30S/LOWER 40S.
TODAY: WITH A STRONG CLOSED UPPER LOW MOVING ACROSS THE GREAT LAKES
AND A HIGH PRESSURE BUILDING OFF TO THE EAST, DRY WEATHER AND
COOLER TEMPERATURES ARE EXPECTED. BREEZY CONDITIONS ARE ALSO
EXPECTED AGAIN TODAY, WITH WINDS W AT 10 TO 15 KT WITH GUSTS UP TO
20 KT OVER LAND. HIGHS WILL REACH INTO THE UPPER 50S TO LOWER 60S.
TONIGHT: W WINDS WILL DIMINISH TO 5 TO 10 KT. LOWS WILL DIP INTO THE
MID TO UPPER 30S INLAND AND LOT TO MID 40S ALONG THE COAST. WE
EXPECT ENOUGH OVERNIGHT WIND TO PREVENT FROST DEVELOPMENT.
LAKE WINDS: EXPECT WINDS AT 15 TO 20 KT WITH GUSTS UP TO 30 OVER
LAKE MOULTRIE THROUGHOUT THE DAY INTO TONIGHT. ALSO, WAVES OF 2-3 FT
ARE EXPECTED. THIS COMBINATION CREATES DANGEROUS WAVE ACTION ON THE
LAKE TONIGHT WITH THE WORST CONDITIONS OCCURRING OVER THE CENTRAL
AND EASTERN PORTIONS OF THE LAKE. BOATERS ARE ENCOURAGED TO REMAIN
OFF THE LAKE.
SHORT TERM /FRIDAY THROUGH SUNDAY/
DEEP MID LEVEL LOW WILL MEANDER OVER THE NORTHEAST ON FRIDAY, BEFORE
EXITING ON SATURDAY. THE PATTERN WILL THEN FLATTEN AND BE REPLACED
BY WEAK RIDGING BY THE END OF THE WEEKEND. AT THE SURFACE, LOW
PRESSURE WILL FINALLY EXIT ALLOWING HIGH PRESSURE TO CONTINUE TO
BUILD OVER THE LOCAL AREA. GUSTY WINDS ARE EXPECTED ON FRIDAY, THEN
THE PRESSURE GRADIENT EASES THROUGH THE WEEKEND. GUSTS OVER LAKE
MOULTRIE COULD APPROACH LAKE WIND ADVISORY CRITERIA FRIDAY INTO
FRIDAY NIGHT, BUT AT THIS POINT REMAINS JUST SHY.
OTHERWISE, EXPECT FULL SUNSHINE WITH MODERATING TEMPERATURES. IT
WILL BE COOLEST ON FRIDAY WHEN HIGHS TOP OUT IN THE MID TO UPPER 50S
(~10 DEGREES BELOW CLIMO). BY SUNDAY, TEMPERATURES WILL RECOVER TO
THE UPPER 60S. LOWS WILL BE CHILLY, FALLING SOLIDLY INTO THE 30S
INLAND OF THE COAST. ATTENTION THEN TURNS TO THE POTENTIAL FOR FROST
OVER FAR INTERIOR AREAS. FOR FRIDAY NIGHT/SATURDAY MORNING, WHILE
TEMPS ARE SUPPORTIVE, WINDS COULD STAY TOO ELEVATED FOR WIDESPREAD
FROST DEVELOPMENT. CERTAINLY NOT OUT OF THE QUESTION TO SEE PATCHY
FROST IN MORE SHELTERED LOCATIONS. FOR SATURDAY NIGHT/SUNDAY
MORNING, WE DID GO ON THE COOLER SIDE OF GUIDANCE WITH IDEAL
RADIATIONAL COOLING CONDITIONS IN PLACE. AS WINDS ARE EXPECTED TO GO
CALM, THIS COULD LEAD TO A HIGHER THREAT FOR FROST. WILL CONTINUE TO
MONITOR TRENDS.
LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/
SURFACE HIGH PRESSURE WILL CONTINUE TO EXTEND INTO THE AREA EARLY
NEXT WEEK, ALTHOUGH A COLD FRONT COULD APPROACH DURING THE LATTER
HALF OF THE PERIOD. STILL SOME UNCERTAINTIES IN THE EVOLUTION OF
THAT FEATURE, WHETHER IT ACTUALLY PASSES THROUGH OR STALLS, SO
CHANGES TO THE FORECAST ARE LIKELY. AT THIS POINT, NO RAIN IS IN THE
FORECAST. TEMPERATURES WILL BE ABOVE CLIMO FOR MONDAY AND TUESDAY
THEN POSSIBLY COOLER FOR WEDNESDAY IF FROPA OCCURS.
AVIATION /09Z THURSDAY THROUGH MONDAY/
21/06Z TAF DISCUSSION:
KCHS/KJZI/KSAV: NOW WITH COLD FRONT OFFSHORE, GUSTY NORTHWEST
WINDS HAVE DEVELOPED AND WILL PERSIST INTO THE DAY THURSDAY.
CLOUDS HAVE NOW CLEARED AND WILL REMAIN CLEAR THROUGH THE REST
OF THE 06Z TAF PERIOD. THUS, VFR WILL PREVAIL.
EXTENDED AVIATION OUTLOOK: VFR. GUSTY WEST WINDS ARE EXPECTED
FRIDAY.
MARINE
THROUGH THURSDAY: NW WINDS WILL BECOME MORE WESTERLY AS WE HEAD
INTO THE AFTERNOON. EXPECT WINDS TO RANGE FROM 10 TO 15 KT WITH
GUSTS UP TO 30 KT. SEAS WILL RANGE FROM 2 TO 4 FT FOR THE
MAJORITY OF THE DAY, AND THEN INCREASING 4 TO 5 FT TONIGHT. A
GALE WARNING REMAINS IN EFFECT FOR THE GEORGIA OFFSHORE WATERS
BEYOND 20 NM WITH HIGH- END SMALL CRAFT ADVISORIES FOR ALL
NEARSHORE LEGS, INCLUDING CHARLESTON HARBOR.
FRIDAY THROUGH TUESDAY: GUSTY WEST WINDS WILL PERSIST OVER THE
COASTAL WATERS FRIDAY INTO FRIDAY NIGHT, MAINTAINING THE ONGOING
SMALL CRAFT ADVISORIES. FOR THE CHARLESTON HARBOR, GUSTS SHOULD FALL
BELOW 25 KT FRIDAY EVENING SO THE ADVISORY IS SCHEDULED TO COME DOWN
AT 23Z/6 PM. CONDITIONS WILL IMPROVE ON SATURDAY, WITH WINDS AND
SEAS REMAINING BELOW ADVISORY LEVELS THROUGH TUESDAY. WINDS
EVENTUALLY TURN SOUTHWEST WITH SPEEDS GENERALLY 15 KNOTS OR LESS AND
SEAS 1-3 FT.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...LAKE WIND ADVISORY UNTIL 11 PM EST THIS EVENING FOR SCZ045.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST FRIDAY FOR AMZ330.
SMALL CRAFT ADVISORY UNTIL 7 AM EST SATURDAY FOR AMZ350-352-
354.
GALE WARNING UNTIL 7 AM EST THIS MORNING FOR AMZ374.
NEAR TERM...DENNIS
SHORT TERM...ETM
LONG TERM...ETM
AVIATION...DENNIS/ETM
MARINE...DENNIS/ETM
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