525
FXUS62 KRAH 180026
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
726 PM EST TUE DEC 17 2024
SYNOPSIS
A BACK DOOR COLD FRONT WILL EDGE INTO THE NORTHERN PIEDMONT TONIGHT
BEFORE LIFTING BACK NORTH IN VIRGINIA WEDNESDAY MORNING. A SERIES OF
COLD FRONTS WILL MOVE ACROSS THE REGION FROM WEDNESDAY NIGHT THROUGH
SATURDAY MORNING.
NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/
AS OF 325 PM TUESDAY...
* PATCHY DENSE FOG POSSIBLE AGAIN TONIGHT WITH FAVORED LOCATIONS
ACROSS THE SOUTHERN PIEDMONT, SANDHILLS, AND INTO THE COASTAL
PLAIN.
REGIONAL SATELLITE IMAGERY SHOWS AN AREA OF MID-LEVEL MOISTURE
STRETCHING FROM FAR SOUTHWEST NC TO JUST NORTH OF CHARLOTTE, THROUGH
THE TRIAD AND JUST WEST OF THE TRIANGLE. RADAR IMAGERY SHOWS
CONFINED POCKETS OF MOSTLY SPRINKLES RIPPLING THROUGH THIS MOISTURE
AXIS AS A SHEAR AXIS WITH EMBEDDED VORTICITY MAXIMUMS SAGS ACROSS
THE AREA. THIS AXIS HAS ALREADY PRODUCED SOME LIGHT SPRINKLES OVER
PORTIONS OF THE TRIAD AND THIS WILL PERIODICALLY CONTINUE INTO THE
EVENING, BUT CONDITIONS WILL REMAIN MOSTLY DRY WITH ONLY ISOLATED
MEASURABLE PRECIPITATION POSSIBLE.
TONIGHT, A SURFACE COLD FRONT ANALYZED AT 18Z REMAINS PINNED UP
AGAINST THE WESTERN SLOPES OF THE APPALACHIAN MOUNTAINS THIS
AFTERNOON. AS THE 1026MB SURFACE HIGH PRESSURE OVER THE SOUTHERN
OHIO VALLEY TRACKS GENERALLY EASTWARD TONIGHT, THIS WILL ALLOW THE
FRONT TO SPILL ACROSS THE VA MOUNTAINS AND DIP INTO THE NORTHERN NC
PIEDMONT LATE TONIGHT INTO EARLY TUES MORNING. SOUTH OF THIS
BACKDOOR FRONT, A LINGERING RESIDUAL CAD AIRMASS REMAINS IN PLACE,
ALTHOUGH MODERATED BY CONSIDERABLE SOLAR HEATING TODAY. THIS
CONTINUED MOIST AIRMASS WILL SUPPORT THE REDEVELOPMENT OF LOW
OVERCAST AND PERHAPS SOME PATCHY/AREAS OF FOG. THE REMNANT CAD HIGH
WILL BECOME MORE DIFFUSE THROUGHOUT THE DAY, BUT CONTINUE TO RIDGE
ACROSS SOUTHERN NC INTO SC AND GA THROUGH TONIGHT AND BE THE FAVORED
AREA FOR POTENTIALLY DENSE FOG. LIGHTS SHOWERS WILL ALSO BE
POSSIBLE, MAINLY ALONG AND NORTH OF THE I-85 CORRIDOR, AS MOIST
ISENTROPIC ASCENT ALONG THE 290K STRENGTHENS ATOP OF THE BACKDOOR
COLD FRONT SPILLING INTO THE AREA FROM THE NORTH. MILD OVERNIGHT
LOWS WILL CONTINUE FOR AT LEAST ONE MORE NIGHT WITH LOWS SETTLING IN
THE MID/UPPER 40S TO LOW 50S.
SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/
AS OF 405 PM TUESDAY...
* A MORE OPTIMISTIC FORECAST FOR WEDNESDAY WITH ANOTHER WARM DAY
AND MAINLY DRY CONDITIONS WITH JUST LIMITED THREAT OF SOME
SPOTTY RAIN/SHOWERS THROUGH EARLY EVENING.
* RAIN CHANCES INCREASE ON WEDNESDAY EVENING INTO THE OVERNIGHT,
ESPECIALLY ACROSS THE EAST WHERE A THUNDERSTORM IS POSSIBLE.
A WARM AND MOIST LOW AND MID-LEVEL SOUTHWESTERLY FLOW WILL BE WELL
ESTABLISHED ACROSS THE REGION ON WEDNESDAY MORNING. A BROAD MID AND
UPPER LEVEL TROUGH COMPOSED OF BOTH A NORTHERN AND SOUTHERN STREAM
JET ACROSS THE WESTERN GREAT LAKES AND WESTERN TN VALLEY ON
WEDNESDAY MORNING WILL SHIFT EAST REACHING THE APPALACHIANS AROUND
MIDNIGHT THURSDAY. THE SOUTHERN PORTION OF THE TROUGH WILL SLOW
REACHING THE COAST OF GA AND THE CAROLINAS BY THURSDAY
AFTERNOON WITH A WESTERLY FLOW SPREADING ACROSS THE CAROLINAS ON
THURSDAY NIGHT AHEAD OF ANOTHER NORTHERN STREAM TROUGH. AT THE
SURFACE, A WEAK FRONTAL ZONE WILL DROP TO AROUND THE NC/VA
BORDER REGION EARLY WEDNESDAY AND LOITER IN THE AREA THROUGH
EARLY AFTERNOON BEFORE LIFTING INTO VA BEFORE A STRONGER FRONT
ASSOCIATED WITH THE MID/UPPER LEVEL TROUGH REACHES THE MOUNTAINS
ON WEDNESDAY EVENING AND THEN REACHING THE COAST BY DAYBREAK
THURSDAY. COOL HIGH PRESSURE WILL BUILD INTO THE REGION LATE
THURSDAY INTO FRIDAY.
IN TERMS OF SENSIBLE WEATHER, WEDNESDAY WILL START OFF WITH AREAS OF
FOG AND THE POTENTIAL FOR AREAS OF DENSE FOG ACROSS THE SOUTHERN AND
SOUTHEASTERN AREAS. A MOIST AND ACTIVE FLOW WILL RESULT IN A FAIR
AMOUNT OF CLOUDINESS ALTHOUGH A LACK OF ORGANIZED FORCING FOR ASCENT
SHOULD LIMIT RAIN CHANCES DURING THE DAY AND THIS IS SUPPORTED
BY JUST ABOUT ALL OF THE CAMS WHICH DEPICT LITTLE PRECIPITATION
OUTSIDE A SPOTTY WARM ADVECTION SHOWER. ACCORDINGLY WE LOWERED
POPS A CONSIDERABLE AMOUNT. TEMPERATURES ON WEDNESDAY WILL
LIKELY BE VERY SIMILAR TO TODAY WITH THE EXCEPTION OF THE
NORTHERN AREAS NEAR THE VA BORDER WHERE THE FRONT LINGERS.
AS THE COLD FRONT AND THE UPPER LEVEL TROUGH APPROACH CENTRAL NC THE
FORCING FOR ASCENT INCREASES AND A BETTER CHANCE OF SHOWERS
DEVELOPS DURING THE EVENING INTO THE OVERNIGHT WITH THE GREATEST
CHANCES ACROSS THE COASTAL PLAIN AND THE EASTERN PIEDMONT. IN
ADDITION, THERE IS A THREAT OF A FEW THUNDERSTORMS WITH THE
GREATEST CHANCE ACROSS THE EAST AND SOUTHEAST AREAS WHILE THE
SPC HAS JUST GENERAL THUNDER OUTLINED, THERE WITH A STRONG
UNIDIRECTIONAL FLOW AND BULK SHEAR ABOVE 25 TO 30KTS, WILL NEED
TO MONITOR THE POTENTIAL FOR A STRONG STORM WEDNESDAY EVENING
ACROSS THE SOUTHERN AND CENTRAL COASTAL PLAIN. LOWS ON
WEDNESDAY NIGHT WILL RANGE FROM THE LOWER 40S NEAR THE VA BORDER
TO THE LOWER 50S ACROSS THE SOUTH.
WESTERLY FLOW AT MID AND UPPER LEVELS ON THURSDAY WILL BECOME
SOUTHWESTERLY ON THURSDAY NIGHT. A COOLER AIRMASS WILL BE IN PLACE
BUT TEMPERATURES WILL STILL RANGE A FEW DEGREES ABOVE AVERAGE. ON
THURSDAY NIGHT A STRENGTHENING VERY LOW LEVEL FLOW WILL RESULT IN
SOME SHALLOW ISENTROPIC LIFT ACROSS THE SOUTHERN AND WESTERN
PIEDMONT DURING THE PREDAWN HOURS. THIS IS NOTED IN BOTH THE NAM AND
THE GFS AND SOME CAMS. INTRODUCED SOME SLIGHT CHANCE POPS FOR THESE
AREAS FOR THURSDAY NIGHT. LOWS ON FRIDAY MORNING WILL RANGE IN THE
LOWER TO MID 30S BUT SHOULD BE WARM ENOUGH IN LOCATIONS WITH
PRECIPITATION TO AVOID ANY FREEZING RAIN. -BLAES
LONG TERM /FRIDAY THROUGH TUESDAY/
AS OF 325 PM TUESDAY...
TEMPERATURES WILL CONTINUE TO COOL THROUGH THE WEEKEND AS AN ARCTIC
AIRMASS SPREADS ACROSS CENTRAL NORTH CAROLINA. THE ASSOCIATED TROUGH
WILL APPROACH THE REGION BY FRIDAY AFTERNOON WHICH COULD ALLOW FOR A
FEW SPRINKLES, HOWEVER IT IS UNLIKELY AS THERE IS A LACK OF
MOISTURE. TEMPERATURES FRIDAY WILL BE IN THE LOW TO MID 50S WITH
LOWS IN THE LOW TO MID 30S. SATURDAY, THE ARCTIC FRONT SHOULD REACH
THE REGION, DROPPING TEMPERATURES FURTHER. HIGH TEMPERATURES ON
SATURDAY WILL BE IN THE 40S, MAYBE REACHING 50 IN THE SOUTH, WHILE
LOWS SATURDAY NIGHT WILL BE IN THE LOW TO MID 20S. EARLY SUNDAY
MORNING, A SHORTWAVE TROUGH SHOULD PASS OVER THE REGION. IF THERE IS
ENOUGH LIFT AND MOISTURE, THIS COULD ALLOW FOR SPOTTY PRECIPITATION,
BUT THIS SEEMS UNLIKELY AT THIS TIME. THE COLD AIR GETS REINFORCED
BY 1040 MB COLD HIGH PRESSURE BUILDING TO OUR NORTH, DECREASING
HIGHS TO THE UPPER 30S TO LOW 40S ON SUNDAY AND LOWS IN THE UPPER
TEENS TO LOW 20S SUNDAY NIGHT. THIS SHOULD ALLOW FOR SUNDAY NIGHT TO
BE THE COLDEST IN THE PERIOD.
HIGH TEMPERATURES ON MONDAY SHOULD STAY SIMILAR TO SUNDAY. A
MID/UPPER LEVEL RIDGE STARTS TO BUILD MONDAY NIGHT, WARMING LOW
TEMPERATURES A FEW DEGREES TO THE LOW TO MID 20S. TEMPERATURES
SHOULD CONTINUE THE SLIGHT WARMING TREND ON TUESDAY, WITH MAXIMUM
TEMPERATURES IN THE MID 40S TO LOW 50S AND LOWS IN THE UPPER 20S TO
LOW 30S.
AVIATION /00Z WEDNESDAY THROUGH SUNDAY/
AS OF 720 PM TUESDAY...
24-HOUR TAF PERIOD: A MOIST AIR MASS IN PLACE AND A BACKDOOR COLD
FRONT PUSHING INTO THE FAR NORTHERN PIEDMONT LATE TONIGHT WILL
RESULT IN AREAS OF LOW STRATUS AT THE NORTHERN TERMINALS (INT, GSO,
RDU, RWI) AFTER ABOUT 05Z. IT SHOULD BEGIN EARLIEST AROUND INT AND
GSO BEFORE SPREADING FARTHER EAST LATER IN THE NIGHT. MVFR
CONDITIONS ARE LIKELY WITH POTENTIAL FOR IFR/LIFR CONDITIONS
ESPECIALLY AT THE TRIAD TERMINALS, WHERE A FEW LIGHT SHOWERS WILL
ALSO BE POSSIBLE. ACROSS THE SOUTHERN PIEDMONT, SANDHILLS, AND
CENTRAL/SOUTHERN COASTAL PLAIN, INCLUDING FAY, THE THREAT WILL BE
MORE DENSE FOG AS OPPOSED TO LOW STRATUS BEGINNING AFTER ABOUT 06Z
TONIGHT AND LIFTING BY MID MORNING TOMORROW. VFR CONDITIONS SHOULD
RETURN ACROSS MOST OF CENTRAL NC BY EARLY AFTERNOON, BUT MVFR MAY
LINGER UNTIL MID AFTERNOON AROUND THE TRIAD. WINDS WILL BE MOSTLY
CALM TONIGHT, BECOMING S/SW AROUND 5-10 KTS DURING THE DAY TOMORROW.
OUTLOOK: AN AREA OF LOW PRESSURE AND ATTENDANT SURFACE COLD FRONT
WILL BE A CHANCE FOR SUB-VFR CONDITIONS IN THE FORM OF SHOWERS AND
ISOLATED THUNDERSTORMS (MAINLY FAY AND RWI WITH A LESSER CHANCE AT
RDU) WED NIGHT INTO THURS MORNING. BEHIND THE FRONT A NORTHWEST TO
NORTHERLY WIND SHIFT AND BRIEFLY GUSTY WINDS WILL BE POSSIBLE.
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...SWIGGETT
NEAR TERM...SWIGGETT
SHORT TERM...BLAES
LONG TERM...HELOCK
AVIATION...DANCO/SWIGGETT
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