238
FXUS62 KCHS 190539
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1239 AM EST TUE NOV 19 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 THIS MORNING/
EARLY THIS MORNING: STILL VERY QUIET ACROSS THE REGION WITH DRY
HIGH PRESSURE IN CONTROL. THIS WILL CONTINUE THROUGH SUNRISE,
WITH JUST SCATTERED CIRRUS PASSING THROUGH OVERHEAD. LOWS ARE ON
TRACK FOR THE LOW TO MID 50S, WITH A FEW ISOLATED LOCATIONS
POSSIBLY JUST DIPPING BELOW 50. THERE WILL AGAIN BE SOME SHALLOW
GROUND FOG AROUND, BUT NO SIGNIFICANT VISIBILITY REDUCTIONS ARE
EXPECTED.
SHORT TERM /6 AM THIS 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 /06Z TUESDAY THROUGH SATURDAY/
VFR CONDITIONS WILL PREVAIL AT KCHS, KJZI, AND KSAV THROUGH 06Z
WEDNESDAY. THERE COULD BE SOME SHALLOW GROUND FOG AT THE
TERMINALS ONCE AGAIN AROUND SUNRISE, BUT NO SIGNIFICANT
VISIBILITY REDUCTIONS ARE EXPECTED. THE POTENTIAL FOR RAIN
SHOWERS WILL INCREASE FROM THE WEST LATE IN THE TAF PERIOD AND
WE HAVE INTRODUCED A MENTION OF VCSH AT ALL 3 SITES IN THE LAST
3-6 HOURS.
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
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.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
NEAR TERM...BSH
SHORT TERM...DPB
LONG TERM...DPB
AVIATION...BSH
MARINE...DPB
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