769
FXUS62 KCHS 032330
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
630 PM EST FRI DEC 3 2021
SYNOPSIS
HIGH PRESSURE WILL PREVAIL THROUGH MONDAY. A COLD FRONT WILL
PUSH OFFSHORE MONDAY NIGHT THEN RETURN TO THE NORTH LATER IN
THE WEEK AS LOW PRESSURE TRACKS WELL TO THE WEST BRINGING
UNSETTLED CONDITIONS TO THE REGION.
NEAR TERM /UNTIL 6 AM SATURDAY MORNING/
EARLY THIS EVENING: NO SIGNIFICANT CHANGES NEEDED TO THE
FORECAST THROUGH SUNRISE. SATELLITE IMAGERY SHOWS SCATTERED
CIRRUS CONTINUING TO SPREAD ACROSS THE AREA. HIGH PRESSURE WILL
BE CENTERED SOUTH OF THE FORECAST AREA ACROSS THE EASTERN GULF
OF MEXICO AND THE FLORIDA PENINSULA THROUGH THE NIGHT. THIS
SETUP WILL DRIVE LIGHT SOUTHWEST TO WESTERLY FLOW ACROSS THE
AREA. SCATTERED CIRRUS SHOULD BE PRESENT THROUGH THE NIGHT BASED
ON UPSTREAM SATELLITE TRENDS. LOWS MOSTLY IN THE UPPER 40S TO
LOW 50S STILL LOOK TO BE ON TRACK. THERE COULD BE SOME PATCHY
FOG, MAINLY ACROSS PORTIONS OF SOUTHEAST SOUTH CAROLINA, BUT IT
SHOULD MOSTLY BE SHALLOW WITH NO SIGNIFICANT VISIBILITY
REDUCTION.
SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/
QUIET CONDITIONS WILL PREVAIL AS WEAK HIGH PRESSURE HOLDS ITS
INFLUENCE ON THE REGION. A WEAK BACKDOOR COLD FRONT WILL ATTEMPT
TO DROP INTO SOUTH CAROLINA LATE SATURDAY NIGHT INTO SUNDAY
MORNING, BUT SHOULD REMAIN TO THE NORTH AS THE PARENT
ANTICYCLONE OVER THE MID-ATLANTIC LOOKS TO REMAIN TOO
PROGRESSIVE IN THE ABSENCE OF SIGNIFICANT DIABATIC COOLING TO
WEDGE THE FRONT THIS FAR SOUTH. INCREASING MOISTURE COUPLED WITH
WEAK CONVERGENCE ALONG THE WEST WALL OF THE GULF STREAM COULD
SPARK A FEW SHOWERS WELL OFFSHORE, BUT THIS ACTIVITY SHOULD
REMAIN AWAY FROM LAND. A WARM, SOUTHWESTERLY WITH H8
TEMPERATURES >11C WILL KEEP SURFACE TEMPERATURES IN THE ABOVE
NORMAL CATEGORY WITH COASTAL TEMPERATURES BEING AUGMENTED BY SEA
BREEZE CIRCULATIONS/ONSHORE FLOW EACH AFTERNOON. HIGHS WILL
WARM INTO THE MID 70S EACH DAY EXCEPT POSSIBLY LIMITED TO THE
LOWER 70S ACROSS SOUTHERN SOUTH CAROLINA SUNDAY AFTERNOON DUE TO
THE PROXIMITY OF THE BACKDOOR FRONT. LOWS WILL DROP INTO THE
MID-UPPER 40S INLAND TO UPPER 50S BEACHES SUNDAY MORNING WITH
LOWER 50S INLAND TO NEAR 60 BEACHES MONDAY MORNING.
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/
A STRONG COLD FRONT WILL APPROACH THE SOUTHEAST U.S. MONDAY AS
NORTHERN STREAM SHORTWAVE DIGS ACROSS THE NORTHERN PLAINS INTO
GREAT LAKES REGION. THE FRONT IS ON TARGET PUSH THROUGH THE AREA
MONDAY NIGHT BEFORE STALLING TUESDAY AS THE SUPPORTING
SHORTWAVE SHEARS OUT ACROSS SOUTHERN QUEBEC. ALTHOUGH BOTH
SURFACE DEWPOINTS AND PWATS AND INCREASE AHEAD OF THE FRONT, THE
DEPTH OF THE MOISTURE DOES NOT LOOK OVERLY IMPRESSIVE WITH MEAN
RH IN THE 850-700 HPA LAYER ONLY RUNNING 50-65%. THIS IS
USUALLY TOO DRY TO SUPPORT MUCH IN THE WAY OF MEANINGFUL
RAINFALL. WITH THE LACK OF STRONG/DEEP QUASI- GEOGRAPHIC FORCING
CORRIDORS NOTED IN THE VARIOUS MODEL TIME HEIGHTS, THE RISK FOR
ANY MEASURABLE RAINFALL LOOKS LIMITED ESPECIALLY GIVEN THE
MARGINAL MOISTURE PROFILES. THE STATIONARY FRONT WILL QUICKLY
RETURN TO THE NORTH TUESDAY NIGHT INTO WEDNESDAY AS DIGGING
SHORTWAVE ENERGY OVER THE SOUTHERN PLAINS INITIATES CYCLOGENESIS
OVER THE TEXAS PANHANDLE. THIS LOW IS FORECAST TO PROPAGATE
QUICKLY TO EAST/NORTHEAST AND REFORM OVER THE MID-ATLANTIC WHILE
DRIVING YET ANOTHER FRONT INTO THE AREA BY MID-LATE WEEK. THERE
REMAINS MUCH UNCERTAINTY ON THE TIMING AND POSITION OF THIS
FRONT NEXT WEEK, BUT SIGNALS ARE THERE THAT RAIN CHANCES WILL
INCREASE ACROSS THE SOUTHEAST SOUTH CAROLINA AND SOUTHEAST
GEORGIA.
AVIATION /00Z SATURDAY THROUGH WEDNESDAY/
VFR CONDITIONS WILL PREVAIL AT KCHS, KJZI, AND KSAV THROUGH 00Z
SUNDAY.
EXTENDED AVIATION OUTLOOK: THERE ARE NO CONCERNS AT THIS TIME.
RAIN WITH A COLD FRONT WEDNESDAY COULD BRING REDUCTIONS IN VSBYS
AND CIGS.
MARINE
TONIGHT: HIGH PRESSURE WILL PREVAIL, LEADING TO A RATHER
RELAXED PRESSURE GRADIENT ACROSS LOCAL WATERS. IN GENERAL,
CONDITIONS WILL REMAIN WELL BELOW SMALL CRAFT ADVISORY CRITERIA
WITH A SOUTH-SOUTHWEST WIND BETWEEN 5-10 KT. SEAS WILL RANGE
BETWEEN 1-2 FT.
SATURDAY THROUGH WEDNESDAY: THERE ARE NO CONCERNS AT THIS TIME.
SOUTH TO SOUTHWEST WINDS WILL PREVAIL FOR MUCH OF THE PERIOD,
EXCEPT FOR TUESDAY WHEN WINDS TURN NORTHEAST BEHIND A COLD
FRONT. THESE NORTHEAST WINDS WILL QUICKLY RETURN MORE SOUTHERLY
BY WEDNESDAY AS THE FRONT LIFTS BACK TO THE NORTH. BOTH WINDS
AND SEAS LOOK TO REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS.
TIDES/COASTAL FLOODING
PERIGEAN SPRING TIDES ARE EXPECTED INTO EARLY NEXT WEEK DUE TO
INFLUENCES FROM THE NEW MOON AND LUNAR PERIGEE. WHILE THE WIND SET-
UP WILL NOT SUPPORT SIGNIFICANT TIDAL DEPARTURES, MINOR COASTAL
FLOODING IS POSSIBLE DURING THE MORNING HIGH TIDES SATURDAY AND
SUNDAY, POSSIBLY EXTENDING INTO MONDAY. COASTAL FLOODING WILL BE
CONFINED TO COASTAL PORTIONS OF CHARLESTON AND COLLETON COUNTIES.
COASTAL FLOOD ADVISORIES COULD BE NEEDED.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
NEAR TERM...BSH
SHORT TERM...
LONG TERM...
AVIATION...BSH
MARINE...DPB
TIDES/COASTAL FLOODING...
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