331
FXUS62 KRAH 161940
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
240 PM EST MON DEC 16 2024
SYNOPSIS
HIGH PRESSURE AND ASSOCIATED COLD AIR DAMMING WILL EXTEND ACROSS THE
PIEDMONT OF THE CAROLINAS, WHILE GRADUALLY WEAKENING, THROUGH
TUESDAY. A SERIES OF COLD FRONTS WILL PROGRESS ACROSS THE REGION
WEDNESDAY NIGHT THROUGH SATURDAY.
NEAR TERM /THROUGH TONIGHT/
AS OF 220 PM MONDAY...
* THREAT FOR DENSE FOG WILL BE MOST PROBABLE ACROSS THE SOUTHERN
PIEDMONT AND SANDHILLS TONIGHT INTO EARLY TUESDAY MORNING.
REGIONAL SATELLITE IMAGERY ALONG WITH 19Z SURFACE OBSERVATIONS SHOW
THE CAD WEDGE BOUNDARY HAS LIFTING THROUGH THE SANDHILLS AND THE
CENTRAL/SOUTHERN COASTAL PLAIN WITH POCKETS OF THINNING/CLEARING
FORMING BETWEEN THE TRIAD AND THE TRIANGLE. THIS BOUNDARY WILL HAVE
A FEW MORE HOURS OF POLEWARD MIXING BEFORE IT IS STUNTED BY BOUNDARY
LAYER STABILITY FROM NOCTURNAL COOLING. OPTICAL DEPTH SATELLITE
IMAGERY FROM GOES16 AND PERIODIC PILOT REPORTS SUGGEST THE THICKEST
CLOUD LAYER STILL REMAINS OVER THE HEART OF THE HYBRID CAD REGIME
ACROSS THE NC FOOTHILLS INTO PORTIONS OF THE NORTHWEST PIEDMONT.
THIS SUGGESTS INT/GSO WILL LIKELY REMAIN LOCKED INTO THE LOW
OVERCAST THROUGH THE REMAINDER OF THE DAYLIGHT HOURS WITH GRADUAL RE-
THICKENING AND LOWERING THROUGH THE OVERNIGHT PERIOD.
A LOBE OF THE CAD SURFACE HIGH ANALYZED AT 15Z OVER THE CHARLOTTE
AREA WILL SETTLE SOUTH OVER CENTRAL SC AND ELONGATE ACROSS THE
SOUTHERN PIEDMONT AND SANDHILLS THROUGH TONIGHT. CALM WINDS WITHIN
THE HIGH AND RESIDUAL HIGH BOUNDARY LAYER MOISTURE WILL BE THE
FAVORED REGION FOR FOG, POTENTIALLY DENSE. ELSEWHERE, LIGHT
STIRRING ON THE NORTHERN PERIPHERY OF THE SURFACE HIGH WILL LIKELY
KEEP THE LOW OVERCAST THAT REDEVELOPS FROM REACHING THE SURFACE AND
PRODUCING ANY VISIBILITY CONCERNS, ALTHOUGH VISIBILITY OF 1 TO 2
MILES WILL CERTAINLY BE POSSIBLE. OVERNIGHT LOWS WILL BE MILD AND
SETTLE IN THE MID/UPPER 40S TO LOW 50S.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/
AS OF 240 PM MONDAY...
UPPER LEVEL DEEPENING TROUGH MOVING ACROSS CONUS TUESDAY AND
WEDNESDAY WITH THE AXIS OVER THE MID-ATLANTIC REGION LATE WEDNESDAY
NIGHT EARLY THURSDAY. AT THE SURFACE, A COLD FRONT EXTENDING FROM NY
DOWN ACROSS THE OH AND TN VALLEY INTO THE SOUTHERN PLAINS WILL
CONTINUE TO SLOWLY SHIFT SOUTH AND EAST THROUGH THE DAY. WHILE
TUESDAY IS EXPECTED TO BE MOSTLY DRY ACROSS THE REGION, CALM TO
LIGHT SW WINDS IN THE MORNING ON TUESDAY WILL RESULT IN PATCHY DENSE
FOG ACROSS THE WESTERN PIEDMONT AND PORTIONS OF THE SANDHILLS
REGION. MOST THE OF THE REGION WILL BE BLANKETED WITH CLOUDS DURING
THE DAY, EXCEPT SOME CLEARING IN THE AFTERNOON ACROSS THE SOUTHERN
COASTAL PLAIN AND PORTIONS OF THE SANDHILLS COULD RESULT IN
TEMPERATURES REACHING THE LOW TO MID 70S IN THOSE AREAS. OTHERWISE,
ELSEWHERE TEMPS ARE ONLY EXPECTED TO REACH THE MID/UPPER 60S. LATE
TUESDAY NIGHT THE FRONTAL BOUNDARY IS EXPECTED TO MOVE EAST OF THE
MOUNTAINS WITH INCREASING RAIN CHANCES FROM WEST TO EAST. ISOLATED
TO SCATTERED SHOWERS ARE EXPECTED EARLY WEDNESDAY MORNING ALONG WITH
ANOTHER ROUND OF PATCHY DENSE FOG AND LOW STRATUS EARLY WEDNESDAY.
THE BEST CHANCE FOR RAIN WILL BE IN THE AFTERNOON AND OVERNIGHT
HOURS. LATEST MODEL DATA HAS SHOWN AN UPTICK IN THUNDER POTENTIAL
ACROSS THE SOUTHEASTERN PORTION OF THE CWA. THE POTENTIAL IS LOW
HOWEVER, WITH ONLY 300-500 J/KG OF SBCAPE, BUT CANT RULE OUT A
COUPLE OF ISOLATED THUNDERSTORMS ESPECIALLY IN AREAS ACROSS THE
SOUTH WHERE TEMPERATURES ARE EXPECTED TO BE IN THE LOW 70S AND DEW
POINTS IN THE MID/UPPER 60S. SPC DOES NOT HAVE OUR AREA IN ANY KIND
OF SEVERE THREAT FOR NOW, BUT WOULDN'T BE SURPRISED IF THEY
INTRODUCED AT LEAST GENERAL THUNDER ACROSS OUR AREA FOR LATE
WEDNESDAY. THE FRONT IS ANTICIPATED TO MOVE ACROSS THE REGION PRE-
SUNRISE THURSDAY MORNING WITH COOL DRY AIR MOVING IN QUICKLY BEHIND
IT. TEMPERATURES WILL PROMPTLY DROP EARLY THURSDAY MORNING AFTER THE
FRONT MOVES THROUGH WITH LOWS RANGING FROM THE LOW 40S NORTH TO LOW
50S SOUTHEAST.
LONG TERM /THURSDAY THROUGH SUNDAY/
AS OF 305 AM MONDAY...
MODELS CONTINUE TO SPEED UP THE DEPARTURE OF THE COLD FRONT, AND
HAVE REMOVED ALL POPS ON THURSDAY. LOW PRESSURE ACROSS THE NORTHERN
PLAINS ON THURSDAY WILL REACH THE OHIO RIVER VALLEY BY FRIDAY
MORNING. THE OHIO RIVER VALLEY LOW WILL WEAKEN AS IT MOVES TO THE
SOUTHEAST, BRINGING LITTLE MORE THAN SKY COVER AND NO CHANCE OF
RAIN. HIGH PRESSURE WILL THEN DOMINATE THE FORECAST OVER THE
WEEKEND, WITH THE CENTER DROPPING FROM MANITOBA ON SATURDAY INTO THE
PLAINS ON SUNDAY. AFTER NEAR NORMAL HIGHS IN THE 50S THURSDAY AND
FRIDAY, NORTHERLY FLOW WILL PLUNGE HIGHS INTO THE 40S ON SATURDAY
AND INTO THE 30S/40S ON SUNDAY. LOWS WILL BE NEAR FREEZING THURSDAY
AND FRIDAY NIGHTS, THEN DROP INTO THE UPPER TEENS AND 20S SATURDAY
NIGHT.
AVIATION /18Z MONDAY THROUGH SATURDAY/
AS OF 110 PM MONDAY...
THE MORE SHALLOW CLOUD LAYER OVER FAY, RDU, AND RWI HAS STEADILY
BEEN ERODING ON THE SOUTHEAST EDGE AND LIFTING GENERALLY NORTHWARD
THROUGH THE LATE MORNING. A GENERAL IMPROVEMENT TO VFR IS EXPECTED
OVER THE NEXT SEVERAL HOURS, LATEST AT RDU. THE HEART OF THE HYBRID
CAD REGIME OVER THE NC FOOTHILLS INTO PORTIONS OF THE NORTHWEST
PIEDMONT MAY SCATTER, MORE LIKELY AT GSO, BUT SHOULD QUICKLY FILL
BACK IN WITH NOCTURNAL STABILIZATION AFTER SUNSET. IFR-LIFR
CONDITIONS ARE EXPECTED TO RAPIDLY BUILD BACK ACROSS THE AREA WITH
THE CONTINUED COOL AND MOIST CAD REGIME STILL LINGERING OVER THE
AREA. DENSE FOG, WITH VISIBILITY BELOW AIRPORT MINIMUMS, WILL BE
MOST PROBABLE IN THE VICINITY OF FAY INTO EARLY TUESDAY MORNING.
OUTLOOK: FLIGHT RESTRICTIONS AT INT/GSO WILL LIKELY FLUCTUATE
BETWEEN IFR-MVFR BY DAY AND LIFR-IFR BY NIGHT THROUGH WEDNESDAY
MORNING, AS COLD AIR DAMMING HOLDS OVER THE NW NC PIEDMONT.
MEANWHILE TO THE EAST, FLIGHT RESTRICTIONS ARE LIKELY TO BE CONFINED
MAINLY TO THE LATE NIGHT-MORNING HOURS THROUGH THE SAME TIME.
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...MWS
NEAR TERM...SWIGGETT
SHORT TERM...CA
LONG TERM...GREEN
AVIATION...SWIGGETT/MWS
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