517
FXUS62 KRAH 202045
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
345 PM EST THU FEB 20 2025
SYNOPSIS
COLD ARCTIC HIGH PRESSURE CENTERED OVER THE MIDWEST WILL
GRADUALLY WEAKEN AND MODIFY AS IT MOVES INTO THE SOUTHERN
APPALACHIANS THROUGH SUNDAY.
NEAR TERM /THROUGH TONIGHT/
AS OF 255 PM THURSDAY...
* WINTER WEATHER ADVISORY FOR BLACK ICE HAS BEEN ISSUED FOR THE
NORTHERN PIEDMONT AND NORTHERN/CENTRAL COASTAL PLAIN FROM 7 PM
TONIGHT THROUGH 10 AM FRIDAY.
* A COLD WEATHER ADVISORY REMAINS IN EFFECT FOR THE COASTAL
PLAIN, SANDHILLS AND SOUTHERN PIEDMONT FOR TONIGHT INTO FRIDAY
MORNING.
REGIONAL RADAR IMAGERY SHOWS THE AREA OF SNOW HAS LOST ITS BANDED
FEATURE AND SURFACE OBSERVATIONS ARE BEGINNING TO IMPROVE UNDERNEATH
THE MOST REFLECTIVE FEATURES. ONLY SOME SCATTERED SNOW SHOWERS
ALONG AND AHEAD OF THE ARCTIC COLD FRONTAL PASSAGE REMAINS, BUT
NO ADDITIONAL ACCUMULATIONS OR IMPACTS TO TRAVEL ARE EXPECTED.
SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW THE BACK EDGE
OF THE OVERCAST CONDITIONS SPREADING WEST ACROSS CENTRAL NC.
THERE ARE STILL PARTLY CLOUDY CONDITIONS IN ITS WAKE OVER THE
PIEDMONT, BUT ENOUGH SUNSHINE IS MAKING IT THROUGH TO
MELT/SUBLIMATE THE SNOWFALL THAT FELL EARLIER THIS MORNING.
SURFACE HEATING AND DEEPENING OF THE MIXED LAYER HAS ALLOWED
GUSTS OF 20 TO 35 MPH TO DEVELOP IMMEDIATELY BEHIND THE COLD
FRONT, WHICH LINES UP FAIRLY WELL WITH THE BACK EDGE OF THE
OVERCAST SKIES AND WHERE DEW POINTS ARE DROPPING INTO THE TEENS.
THE ARCTIC FRONT WILL CONTINUE TO SPREAD ACROSS THE REGION THROUGH
TONIGHT AND SUSTAINED CAA AND PRESSURE RISES WILL KEEP WIND GUSTS
CONTINUING ACROSS THE AREA THROUGH AROUND MIDNIGHT BEFORE
GRADUALLY WEAKENING THROUGH THE NIGHT. CONTINUED LIGHT STIRRING
AND BITTER COLD TEMPERATURES IN THE LOW 20S TO TEENS RESULT IN
WIND CHILLS IN THE TEENS TO SINGLE DIGITS. A COLD WEATHER
ADVISORY WILL BE IN EFFECT TONIGHT FOR THE SOUTHERN PIEDMONT,
SANDHILLS, AND COASTAL PLAIN WHERE THE CRITERIA IS 10F OR LOWER
UNTIL 10 AM FRIDAY MORNING.
FINALLY, A WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR TONIGHT FOR
THE AREAS FROM RALEIGH NORTH AND EAST. THIS GENERAL AREA HAD THE
GREATEST STORM TOTAL SNOWFALL IN THE PAST 36 HOURS AND WILL LIKELY
SEE THE LEAST AMOUNT OF SUNSHINE TODAY. ALTHOUGH SOME
MELTING/SUBLIMATING IS POSSIBLE THIS AFTERNOON FROM SOME PEEKS OF
SUN AND VERY DRY AIR BEHIND THE ARCTIC FRONT. SURFACE TEMPERATURES
WELL BELOW FREEZING WILL ALLOW ANY MELTING TO REFREEZE AFTER SUNSET.
MOSTLY CLEAR SKIES FRI MORNING SHOULD ALLOW FOR EFFICIENT
MELTING/DRYING OF ROAD CONDITIONS AFTER 10 AM.
SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/
AS OF 342 PM THURSDAY...
ENHANCED WNWLY FLOW ALOFT WILL PROMOTE CONSIDERABLY DRY AIR THROUGH
THE ATMOSPHERIC COLUMN WITH PWAT % OF NORMAL DROPPING TO ~15 TO 20%.
DEW POINTS FRIDAY AFTERNOON WILL MIX OUT INTO THE UPPER SINGLE
DIGITS TO THE LOWER TO MID TEENS. AT THE SFC, STRONG HIGH PRESSURE
WILL LARGELY REMAIN ANCHORED OVER THE CENTRAL US WHICH WILL EXTEND
PRIMARILY NWLY SFC FLOW INTO CENTRAL NC. THE PRESSURE GRADIENT WILL
BE STRONGEST FRIDAY MORNING, BUT SHOULD RELAX THROUGHOUT THE DAY. AS
SUCH, ANY EARLY MORNING GUSTINESS WILL QUICKLY SUBSIDE BY MID TO
LATE FRIDAY MORNING.
THE POST-FRONTAL COLD AIR MASS WILL LINGER FRIDAY, WITH HIGHS
GENERALLY STRUGGLING TO REACH THE LOWER 40S. LOCATIONS ALONG AND
EAST OF I-95, WHERE HIGHER SNOWFALL TOTALS AND GENERALLY WHERE
CLOUDS HUNG ON THE LONGEST THURSDAY, WILL LIKELY ONLY SEE HIGHS PEAK
IN THE MID TO UPPER 30S.
COLD OVERNIGHT LOWS ARE EXPECTED AGAIN FRIDAY NIGHT, BUT SOME
UPSTREAM MID TO HIGH LEVEL CLOUDINESS WILL (AND A BIT INCREASE IN
LOW-LEVEL THICKNESSES) SHOULD COMPARATIVELY LIMIT OVERNIGHT LOWS TO
THE UPPER TEENS/LOWER 20S.
LONG TERM /SATURDAY THROUGH THURSDAY/
AS OF 342 PM THURSDAY...
AFTER LARGELY ZONAL FLOW ALOFT EARLY SATURDAY, A MID-LEVEL VORTICITY
PERTURBATION WILL DIVE THROUGH THE SOUTHEAST SATURDAY NIGHT INTO
SUNDAY MORNING. A SOUTHERN-STREAM SHORT-WAVE WILL THEN GLANCE BY TO
OUR SOUTH SUNDAY INTO MONDAY. BEYOND MONDAY, A STRONG SHORT-WAVE
WILL DRIVE THROUGH THE OHIO VALLEY AND MID-ATLANTIC TUESDAY INTO
WEDNESDAY, FOLLOWED BY THE ARRIVAL OF A POTENTIALLY DEEPER LONG-WAVE
TROUGH THURSDAY INTO FRIDAY.
CHILLY SFC HIGH PRESSURE WILL SETTLE OVER CENTRAL NC SATURDAY BEFORE
SHIFTING OFFSHORE THROUGH SUNDAY MORNING. THIS WILL PROMOTE DRY BUT
CHILLY WEATHER WITH HIGHS PEAKING IN THE MID TO UPPER 40S. LOW-
LEVEL THICKNESSES ARE EXPECTED TO INCREASE SOME SATURDAY NIGHT,
WHICH SHOULD PROMOTE A BIT WARMER OVERNIGHT LOWS IN THE MID TO UPPER
20S.
SSELY RETURN FLOW AROUND THE OFFSHORE SFC HIGH WILL PROMOTE SOME
MODERATION IN TEMPERATURES SUNDAY, WITH HIGHS REACHING THE MID TO
UPPER 50S. GUIDANCE SUGGESTS THAT A COASTAL WAVE ASSOCIATED WITH THE
AFOREMENTIONED SOUTHERN STREAM SHORT-WAVE MAY DEVELOP SUNDAY NIGHT
INTO MONDAY MORNING. HOWEVER, ENSEMBLE GUIDANCE IS IN GOOD AGREEMENT
LARGELY SHUNTING ALL ANOMALOUS MOISTURE ASSOCIATED WITH THIS SYSTEM
TO OUR SOUTH AND OFFSHORE. AS SUCH, WILL CONTINUE TO HIGHLIGHT A DRY
FORECAST THROUGH EARLY TUESDAY. A SECONDARY SHORT-WAVE WILL DIVE
INTO THE MID-ATLANTIC TUESDAY INTO WEDNESDAY. WHILE THE NBM CAME IN
MOSTLY DRY FOR OUR AREA TUESDAY EVENING, THERE WAS ENOUGH SIGNAL IN
THE ENSEMBLE PROBABILITIES FOR MEASURABLE RAINFALL TO WARRANT
SLIGHT CHANCE POPS ACROSS OUR NORTHERN AREAS TUESDAY
AFTERNOON/EVENING (FORECAST SOUNDINGS ALSO CONCUR THAT ENOUGH
SATURATION MAY BE PRESENT TO PRODUCE LIGHT RAIN ALONG THE NC/VA
BORDER). OVERALL THOUGH, THIS SHOULD BE A NON-IMPACTFUL EVENT.
AS WE PIVOT TO MID TO LATE WEEK, ENSEMBLES ARE IN DECENT AGREEMENT
SUGGESTING A DEEPER LONG-WAVE TROUGH MAY DIG AND LIFT ACROSS THE
EASTERN SEABOARD. THERE'S A BIT OF DISAGREEMENT WRT TO TIMING, BUT
ANOMALOUS MOISTURE AND ENHANCED PRECIPITATION CHANCES SHOULD START
TICKING UP THURSDAY INTO FRIDAY. FOR NOW, STUCK WITH THE RAW NBM
OUTPUT INCREASING RAINFALL CHANCES TO HIGH-END CHANCE POPS BY
THURSDAY AFTERNOON. DETAILS TO FOLLOW AS WE GET CLOSER TO MIDDLE OF
NEXT WEEK.
AVIATION /18Z THURSDAY THROUGH TUESDAY/
AS OF 1217 PM THURSDAY...
A BAND OF LIGHT TO MODERATE SNOW CONTINUES TO EJECT EAST ACROSS THE
CENTRAL NORTHERN PARTS OF CENTRAL NC THIS AFTERNOON. KRDU WILL
LIKELY SEE CONTINUED REDUCED VISIBILITIES FOR ANOTHER HOUR OR SO BUT
THE BACK EDGE OF THE SNOWBAND IS QUICKLY APPROACHING. KRWI HAS JUST
DROPPED VIA THE SNOW, AND WILL LIKELY CONTINUE TO REMAIN SUB-VFR
WITH LOW VISBYS FOR AT LEAST A FEW MORE HOURS UNTIL THE BAND CLEARS
TO OUR EAST. KINT/KGSO HAVE ALREADY RETURNED TO VFR, AND SUSPECT
THAT KFAY WILL LIKELY REMAIN VFR (SANS SOME FLEETING MVFR CEILINGS
THE NEXT FEW HOURS).
ANY LINGERING MVFR CEILINGS WILL QUICKLY DISSIPATE WITH PASSAGE OF
AN ARCTIC FRONT (WHICH HAS ALREADY PASSED THROUGH THE TRIAD SITES).
BEHIND THIS FRONT, EXPECT IMMEDIATE 20 TO 25 KT NWLY SFC GUSTS
(ALREADY SHOWING IN THE TRIAD). THESE GUSTS WILL CONTINUE INTO THE
EARLY OVERNIGHT PERIOD, BEFORE SUBSIDING SOME THROUGH FRIDAY MORNING
(THEY STAY UP LONGEST IN THE TRIAD).
HIGH PRESSURE WILL SETTLE IN BEHIND THE FRONT PROMOTING DRY VFR
CONDITIONS THROUGH THE END OF THE 24 HOUR TAF PERIOD.
OUTLOOK: VFR CONDITIONS ARE GENERALLY EXPECTED THROUGH THE PERIOD.
HOWEVER, A SOUTHERN STREAM WAVE/POTENTIAL COASTAL LOW MAY PROMOTE
MID LEVEL CLOUDINESS LATE SUNDAY INTO EARLY MONDAY MORNING. AS OF
NOW, SUSPECT THAT VFR CONDITIONS WILL PERSIST, BUT THERE COULD BE A
BRIEF PERIOD OF SUB-VFR CONDITIONS IN THE SOUTH AND EAST DURING THIS
TIME.
RAH WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
FRIDAY FOR NCZ007>011-023>028-040>043-076>078.
COLD WEATHER ADVISORY FROM 10 PM THIS EVENING TO 10 AM EST
FRIDAY FOR NCZ011-027-028-042-043-073>078-083>086-088-089.
SYNOPSIS...BLAES
NEAR TERM...SWIGGETT
SHORT TERM...LUCHETTI
LONG TERM...LUCHETTI
AVIATION...LUCHETTI
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