414
FXUS62 KRAH 210512
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1210 AM EST FRI FEB 21 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 1050 PM THURSDAY...
* WINTER WEATHER ADVISORY FOR BLACK ICE IS IN EFFECT FOR THE
NORTHEASTERN PIEDMONT AND NORTHERN/CENTRAL COASTAL PLAIN THROUGH
10 AM FRIDAY.
* A COLD WEATHER ADVISORY IS IN EFFECT FOR THE COASTAL PLAIN,
SANDHILLS AND SOUTHERN PIEDMONT THROUGH 10 AM FRIDAY.
SURFACE OBSERVATIONS INDICATE THE ARCTIC FRONT HAS CLEARED CENTRAL
NC, WITH DEW POINTS DROPPING INTO THE SINGLE DIGITS FOR MUCH OF THE
REGION, EXCEPT TEENS IN THE FAR SE. SLIGHTLY LOWERED FORECAST DEW
POINTS AS THEY ARE DROPPING QUICKLY DUE TO THE NW FLOW. A PRESSURE
GRADIENT BETWEEN THE DEPARTING LOW EAST OF NEW ENGLAND AND A STRONG
1040+ MB ARCTIC HIGH CENTERED OVER EASTERN KS/NE AND MO WILL KEEP NW
WINDS ELEVATED AROUND 5-10 MPH THROUGH THE OVERNIGHT HOURS. WHILE
THERE ARE STILL A FEW OBSERVED GUSTS AROUND 15-20 MPH, THESE SHOULD
CONTINUE TO BECOME LESS FREQUENT AS THE NIGHT GOES ON.
TEMPERATURES HAVEN'T COOLED QUITE AS QUICKLY AS EXPECTED SO FAR,
LIKELY DUE TO THE WINDS, BUT THEY ARE STILL EXPECTED TO DROP INTO
THE MID-TO-UPPER-TEENS FOR MUCH OF THE AREA BY EARLY FRIDAY MORNING
AS WINDS LESSEN AND WITH THE CLEAR SKIES AND SNOW COVER IN PLACE.
THE COMBINATION OF THESE TEMPERATURES AND CONTINUED STIRRING WILL
RESULT IN WIND CHILLS DROPPING AS LOW AS THE UPPER SINGLE DIGITS AND
LOWER TEENS. SO WHILE IT IS BORDERLINE, CONTINUE THE COLD WEATHER
ADVISORY FOR AREAS WHERE THE CRITERIA IS 10F OR LOWER, WHICH
INCLUDES THE COASTAL PLAIN, SANDHILLS AND SOUTHERN PIEDMONT. BE SURE
TO BUNDLE UP IF YOU HAVE TO GO OUTSIDE.
THE OTHER CONCERN TONIGHT WILL BE THE BLACK ICE POTENTIAL, AS
TEMPERATURES DROP WELL BELOW FREEZING AND ANY RUNOFF FROM MELTING
SNOW REFREEZES. SO CONTINUE THE WINTER WEATHER ADVISORY FOR BLACK
ICE ACROSS AREAS THAT SAW THE MOST SNOW AND LEAST SUN TODAY. THE NW
WINDS, VERY LOW DEW POINTS, AND FULL SUNSHINE WILL HELP WITH QUICK
EVAPORATION AND MELTING OF ICE ON THE ROADS BY MID TO LATE MORNING
ON FRIDAY.
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 /05Z FRIDAY THROUGH TUESDAY/
AS OF 1210 AM FRIDAY...
TAF PERIOD: HIGH CONFIDENCE IN VFR CONDITIONS THROUGH THE NEXT 24
HOURS. THERE SHOULD BE LITTLE MORE THAN A PASSING HIGH CLOUD. MODELS
HAVE BEEN TRENDING DOWN WITH MODEL GUSTS FOR LATE FRIDAY
MORNING/AFTERNOON, AND HAVE TRENDED VALUES DOWN WITH THE 06Z TAF
PACKAGE. IF THE TREND CONTINUES, MAY EVEN BE ABLE TO REMOVE THE
GUSTS AT EASTERN SITES WITH THE 12Z PACKAGE.
OUTLOOK: VFR CONDITIONS ARE EXPECTED INTO NEXT WEEK, WITH A SLIGHT
CHANCE OF SHOWERS ENTERING THE FORECAST FOR TUESDAY.
RAH WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY UNTIL 10 AM EST FRIDAY FOR NCZ007>011-
023>028-040>043-076>078.
COLD WEATHER ADVISORY UNTIL 10 AM EST FRIDAY FOR NCZ011-027-028-042-
043-073>078-083>086-088-089.
SYNOPSIS...BLAES
NEAR TERM...DANCO
SHORT TERM...LUCHETTI
LONG TERM...LUCHETTI
AVIATION...GREEN
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