591
FXUS62 KCHS 190005
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
705 PM 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 /UNTIL 6 AM TUESDAY MORNING/
AS OF THIS EVENING, MID AND HIGH CLOUDS WILL INCREASE THROUGH
THE REST OF TONIGHT AS A COLD FRONT TRACKS THROUGH THE DEEP
SOUTH. SURFACE OBSERVATIONS INDICATE THAT WINDS ACROSS THE
INLAND COUNTIES HAVE DECOUPLED AND WINDS ALONG THE COAST REMAIN
AT 5 MPH. THE UPDATED FORECAST WILL FEATURE DRY CONDITIONS WITH
GRADUALLY INCREASING CLOUD COVER FOR TONIGHT. AS WE HEAD INTO
THE MORNING HOURS, HIGH CLOUDS LOOK TO BE ARRIVING BEFORE
DAYBREAK AND THUS KEEPS THE POTENTIAL FOR FOG VERY LOW AND
DECIDED TO KEEP IT OUT OF THE FORECAST AT THIS TIME.
WHILE THERE WILL BE AN INCREASE IN HIGH LEVEL CLOUDS THROUGH
THE NIGHT AS THEY ARRIVE FROM THE WEST, ANY SHOWERS ASSOCIATED
WITH THE UPSTREAM FRONTAL SYSTEM WILL STAY OUTSIDE THE AREA WITH
LARGE SCALE SUBSIDENCE IN PLACE. IT'LL BE A WARMER NIGHT THAN
RECENTLY WITH THESE CLOUDS MOVING IN, ALONG WITH HIGHER DEW
POINTS IN THE SOUTHWEST SYNOPTIC FLOW. WE'RE LOOKING AT UPPER
40S AND LOWER 50S WELL INLAND, 55-60F CLOSER TO THE COAST.
SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/
TUESDAY: ALOFT, A LARGE RIDGE EXTENDING ACROSS THE SOUTHEAST UNITED
STATES WILL SHIFT EAST WITH THE APPROACH OF H5 VORT ENERGY IN
ADVANCE OF A LARGE TROUGH OVER THE CENTRAL UNITED STATES. AT THE
SFC, A REMNANT LOW POSITIONED ACROSS THE SOUTHERN GULF OF MEXICO
WILL SHIFT NORTH AND BECOME ABSORBED BY A COLD FRONT TRAVERSING THE
DEEP SOUTH. THE BULK OF MOISTURE AND FORCING IS EXPECTED TO REMAIN
WEST TO THE LOCAL AREA FOR MUCH OF THE DAY, BEFORE SHIFTING ACROSS
THE REGION DURING THE NIGHT. RAIN/SHOWERS SHOULD BREAKOUT DURING THE
NIGHT WITH THE FIRST WAVE OF H5 VORTICITY CROSSING THE LOCAL AREA,
BUT PRECIP COVERAGE WILL LIKELY DEPEND ON HOW ORGANIZED CONVECTION
BECOMES ACROSS THE NORTH-NORTHEAST GULF COAST, WHICH COULD LIMIT THE
PROGRESSION OF MOISTURE/INSTABILITY NORTH INTO THE LOCAL AREA. HIGH
TEMPS WILL BE QUITE MILD, SOME 5-8 DEGREES ABOVE NORMAL, GENERALLY
PEAKING IN THE MID TO UPPER 70S ACROSS MUCH OF THE AREA. OVERNIGHT
LOWS WILL ALSO REMAIN WARMER THAN THE PREVIOUS DAY, GENERALLY ONLY
DIPPING INTO THE LOW-MID 60S.
WEDNESDAY: THE FIRST WAVE OF RAIN/SHOWER ACTIVITY WILL LIKELY HAVE
SHIFTED OFFSHORE IN ADVANCE OF A COLD FRONT PROGGED TO ENTER THE
REGION LATE DAY AND/OR EARLY NIGHT. HOWEVER, FORCING ALONG THE BACK
EDGE OF AMPLE MOISTURE (PWATS AROUND 1.5 INCHES) SHOULD FAVOR FEW TO
SCATTERED SHOWERS DURING THE DAY BEFORE DRIER AIR OVERSPREADS THE
SOUTHEAST UNITED STATES BY EARLY NIGHT. TEMPS WILL ONCE AGAIN BE
WELL ABOVE NORMAL AHEAD OF THE FRONT, PEAKING IN THE MID-UPPER 70S
ACROSS MOST AREAS. WEST-SOUTHWEST WINDS COULD ALSO BECOME GUSTY BY
MID-LATE AFTERNOON, THEN PERSIST INTO THE NIGHT AS THE ONSET OF COLD
AIR ADVECTION TAKES PLACE IN WAKE OF THE FROPA. TEMPS WILL BE
TRENDING ON THE COOLER SIDE HEADING THROUGH THE NIGHT, WITH LOW
TEMPS GENERALLY RANGING IN THE LOW-MID 40S INLAND TO UPPER 40S NEAR
THE COAST.
THURSDAY: DRY AND MUCH COOLER WEATHER IS EXPECTED WITH SFC HIGH
PRESSURE BUILDING ACROSS THE AREA UNDER A LARGE MID-UPPER LVL LOW
CENTERED ACROSS THE EASTERN GREAT LAKES. HOWEVER, GUSTY WEST WINDS
ARE LIKELY THROUGH THE AFTERNOON WITH STRONGEST GUSTS ALONG THE
COASTS (25-30 MPH). TEMPS WILL BE NOTICEABLY COOLER WITH HIGHS BELOW
NORMAL, GENERALLY RANGING IN THE UPPER 50S WELL INLAND TO LOWER 60S
ACROSS MOST AREAS.
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 WEDNESDAY NIGHT THROUGH THURSDAY NIGHT.
LONG TERM /THURSDAY NIGHT THROUGH MONDAY/
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 /00Z TUESDAY THROUGH SATURDAY/
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT KCHS, KJZI, AND KSAV
THROUGH 00Z WEDNESDAY. SINCE THERE WILL BE AN INCREASE IN CLOUD
COVER, THERE WON'T BE ANYTHING MORE THAN SOME SHALLOW GROUND
FOG AT THE SITES DURING THE LATE NIGHT HOURS, POSSIBLY
DISSIPATING BEFORE DAYBREAK. A COLD FRONT WILL START TO
APPROACH FROM THE WEST AROUND 14Z TUESDAY RESULTING IN SW 5 TO
10 KTS AT EACH TERMINAL.
EXTENDED AVIATION OUTLOOK: VFR CONDITIONS WILL PREVAIL THROUGH
TUESDAY AT CHS/JZI/SAV TERMINALS. BRIEF FLIGHT RESTRICTIONS ARE
POSSIBLE TUESDAY NIGHT INTO WEDNESDAY WITH SHOWERS IN ADVANCE OF AND
DURING A COLD FRONT PASSING ACROSS THE REGION. VFR CONDITIONS RETURN
AND PERSIST THURSDAY THROUGH SATURDAY. GUSTY WEST WINDS ARE LIKELY
AT ALL TERMINALS THURSDAY AND FRIDAY.
MARINE
THIS EVENING AND TONIGHT: HIGH PRESSURE CENTERED NOT FAR TO THE
SOUTHEAST, AS A FRONTAL SYSTEM IS FOUND FAR UPSTREAM FROM THE UPPER
MIDWEST TO WESTERN GULF OF MEXICO. SEA BREEZE INFLUENCES WILL WANE
THIS EVENING, AND A GENERAL S-SW FLOW WILL PREVAIL THROUGH THE
NIGHT, NO HIGHER THAN 10 OR 15 KT. SEAS ARE HELD TO 2 FEET OR LESS.
TUESDAY THROUGH SATURDAY: CONDITIONS WILL REMAIN BELOW SMALL CRAFT
ADVISORY CONDITIONS TUESDAY. A STRONG COLD FRONT WILL THEN MOVE
ACROSS THE REGION LATE WEDNESDAY INTO EARLY THURSDAY, LEADING
TO STRONG COLD AIR ADVECTION ACROSS LOCAL WATERS AND DETERIORATING
CONDITIONS WEDNESDAY NIGHT INTO THURSDAY. SMALL CRAFT ADVISORIES
WILL LIKELY BE NEEDED WEDNESDAY NIGHT THROUGH AT LEAST FRIDAY
FOR MOST WATERS. THERE CONTINUES TO BE A RISK FOR GALES ACROSS A
PORTION OF LOCAL WATERS POST FROPA WEDNESDAY NIGHT AND THURSDAY
NIGHT. HOWEVER, THE EVENT COULD BE MARGINAL WITH 1000MB GEOSTROPHIC
WINDS GENERALLY PEAKING AROUND 30-35 KT DURING THE 48-HOUR SPAN.
IMPROVEMENT IS EXPECTED SATURDAY AS THE PRESSURE GRADIENT EASES
WITH HIGH PRESSURE EXPANDING ACROSS THE REGION.
TIDES/COASTAL FLOODING
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...NONE.
MARINE...NONE.
NEAR TERM...DENNIS
SHORT TERM...DPB
LONG TERM...DPB
AVIATION...DENNIS
MARINE...DPB
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