473
FXUS62 KRAH 191202
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
702 AM EST WED FEB 19 2025
SYNOPSIS
HIGH PRESSURE WILL BUILD ACROSS VA AND NC THIS MORNING. LOW PRESSURE
WILL TRACK ACROSS AND JUST OFFSHORE THE GULF AND SOUTH ATLANTIC
STATES LATER TODAY AND TONIGHT. ARCTIC HIGH PRESSURE WILL FOLLOW AND
MIGRATE FROM THE NORTHERN PLAINS TO THE MIDDLE ATLANTIC, WHILE
WEAKENING AND MODIFYING, THROUGH THE WEEKEND.
NEAR TERM /THROUGH THURSDAY/
AS OF 255 AM WEDNESDAY...
LOW PRESSURE IS DEVELOPING OFF THE LOUISIANA COAST AND WILL BE
MOVING TO THE EAST AT THE SAME TIME THAT A SECOND LOW WILL BE
DEVELOPING OFF THE GEORGIA COAST AND MOVING ALONG THE ATLANTIC
COASTLINE. IT IS NOTABLE THAT THERE IS SOME CONVECTION CURRENTLY
OCCURRING ALONG THE GULF COAST, AS PREVIOUS RESEARCH HAS SHOWN THAT
WHEN CONVECTION OCCURS ALONG THE GULF, IT CAN INTERRUPT MOISTURE
TRANSPORT INTO THE CAROLINAS. WITH THE LATEST ROUND OF MODEL
GUIDANCE, THERE HAS BEEN A SLIGHT REDUCTION IN THE AMOUNT OF LIQUID
PRECIPITATION THAT WILL FALL ACROSS THE CAROLINAS, ALSO RESULTING IN
A SLIGHT REDUCTION IN SNOW AND FREEZING RAIN ACCUMULATION. NO
CHANGES HAVE BEEN MADE TO ADVISORIES OR WARNINGS, AS THE REDUCTION
IN LIQUID PRECIPITATION WAS LESS TO THE EAST WHERE THE WARNINGS ARE
LOCATED. IN THE COUNTIES WITH ADVISORIES, THE CRITERIA OF 1 INCH OF
SNOW OR ANY ACCUMULATION OF FREEZING RAIN ARE STILL EXPECTED TO BE
MET.
THE CHANCE OF PRECIPITATION IS STILL EXPECTED TO BEGIN AROUND
DAYBREAK ACROSS THE NORTHWEST, SLOWLY SPREAD ACROSS THE REST OF THE
AREA, AND QUICKLY RAMP UP DURING THE LATE MORNING AND EARLY
AFTERNOON HOURS. THE HIGHEST ACCUMULATION IS EXPECTED TO HAPPEN
DURING THE AFTERNOON, ESPECIALLY ALONG AND EAST OF US-1. COUNTIES
ALONG THE NORTHERN TIER OF THE FORECAST AREA ARE EXPECTED TO REMAIN
ALL SNOW, WITH ALL OTHER COUNTIES EXPECTED TO RECEIVE A MIX OF SNOW,
SLEET, AND FREEZING RAIN. THE CHANCE FOR LIQUID RAIN SHOULD REMAIN
MOSTLY TO THE SOUTH OF NC 24. THE MODELS HAVE STARTED TO SHOW A
TREND FOR PRECIPITATION TO EXIT TO THE EAST SLIGHTLY QUICKER. THE
OFFICIAL FORECAST MAINTAINS CHANCE POPS IN THE TRIAD INTO THE
EVENING HOURS, ALTHOUGH PRECIPITATION MAY BE EAST OF THE AREA BY
THAT TIME. THE BULK OF THE PRECIPITATION WILL LIKELY BE TO THE EAST
OF I-95 BY MIDNIGHT, AND MANY LOCATIONS SHOULD HAVE A SEVERAL HOUR
BREAK IN PRECIPITATION OVERNIGHT. HOWEVER, THERE IS GREATER
CONSISTENCY IN SHOWING A ROUND OF SNOW MOVING THROUGH MANY LOCATIONS
THURSDAY MORNING WITH AN UPPER LOW THAT WILL PASS ALONG THE MASON-
DIXON LINE. THIS SNOW SHOULD BE LIGHT, BUT COULD RESULT IN A COUPLE
TENTHS OF ADDITIONAL SNOW DURING THE THURSDAY MORNING COMMUTE. ALL
SNOW SHOULD MOVE TO THE EAST OF CENTRAL NC BY THURSDAY AFTERNOON.
DAYTIME HIGHS TODAY WILL RANGE FROM THE UPPER 20S TO THE UPPER 30S,
AND WILL LIKELY OCCUR IN THE LATE MORNING, WITH EVAPORATIVE COOLING
RESULTING IN TEMPERATURES REMAINING STEADY OR FALLING THROUGH THE
REST OF THE DAY. LOWS TONIGHT WILL BE IN THE 20S. HIGHS ON THURSDAY
WILL RANGE FROM THE LOW 30S TO THE LOW 40S. GUSTY WINDS ARE STILL
EXPECTED ON THURSDAY WITH AN INCREASED PRESSURE GRADIENT BETWEEN THE
DEPARTING LOW OVER THE ATLANTIC AND HIGH PRESSURE THAT WILL DOMINATE
THE CENTRAL UNITED STATES, BUT HAVE SLIGHTLY REDUCED THE INHERITED
FORECAST VALUES. STILL, GUSTS ARE LIKELY TO BE ANYWHERE FROM 25-35
MPH ACROSS THE REGION, WITH THE HIGHEST VALUES IN THE TRIAD.
SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/
AS OF 220 AM WEDNESDAY...
* VERY COLD CONDITIONS THURSDAY AND FRIDAY NIGHTS WITH LOWS 14 TO 20
DEGREES BELOW AVERAGE.
* WIND CHILL VALUES ON FRIDAY MORNING WILL RANGE BETWEEN 10 AND 15
DEGREES AND THEY COULD BRIEFLY DROP INTO THE SINGLE DIGITS.
COLD ARCTIC HIGH PRESSURE ACROSS THE CENTRAL PLAINS ON THURSDAY
EVENING WILL EXTEND INTO THE MIDDLE ATLANTIC THROUGH EARLY SATURDAY
MORNING. THE COMBINED CIRCULATION AROUND THE HIGH AND THE DEPARTING
WINTER STORM WITH RESULT IN A PERIOD OF COLD ADVECTION AND VERY
COLD CONDITIONS. LOW LEVEL THICKNESS VALUES ARE FORECAST TO
DROP INTO THE 1260'S ON FRIDAY MORNING SUPPORTING LOWS IN THE
MID TEENS TO AROUND 20 DEGREES. THESE TEMPERATURES COMBINED A
NORTHWEST WIND OF 5 TO 10 MPH WILL RESULT IN WIND CHILLS VALUES
OF 10 TO 15 DEGREES WHICH MAY BRIEFLY DROP INTO THE SINGLE
DIGITS FRIDAY MORNING.
EXPECT COLD AND FAIR WEATHER ON FRIDAY WITH BRIGHT SUNSHINE AND
CHILLY TEMPERATURES. HIGHS IN THE IN THE NORTHERN COASTAL PLAIN AND
VA BORDER COUNTIES WILL LIKELY BE CHILLED BY SNOW/ICE COVER AND
MELTING WITH HIGHS IN THE UPPER 30S. MOST OTHER LOCATIONS WILL HAVE
HIGHS IN THE LOWER 40S. THESE HIGHS ARE 12 TO 20 DEGREES BELOW
AVERAGE.
ANOTHER CHILLY NIGHT IS EXPECTED ON FRIDAY NIGHT. A NORTHERN STREAM
WAVE WILL APPROACH FROM THE MO/OH VALLEYS AND COULD RESULT IN SOME
INCREASED HIGH CLOUDS. LOW LEVEL THICKNESS VALUES WILL WARM 20 TO
25M FROM THE PREVIOUS 24 HOURS. THIS SHOULD RESULT IN A NIGHT THAT
WONT BE AS COLD AS THURSDAY NIGHT BUT WITH A SHALLOW COLD AIRMASS IN
PLACE LOWS SHOULD RANGE IN THE UPPER TEENS TO LOWER 20S. -BLAES
LONG TERM /SATURDAY THROUGH TUESDAY/
AS OF 250 AM WEDNESDAY...
NWP GUIDANCE NOTES THAT A MID AND UPPER LEVEL SHORT WAVE TROUGH WILL
MOVE FROM THE TN VALLEY ON SATURDAY MORNING AND OFF THE CAROLINA
COAST ON SATURDAY NIGHT. THIS FEATURE HAS LIMITED MOISTURE BUT SOME
GUIDANCE NOTES THAT A SURFACE REFLECTION MAY DEVELOP NEAR AND JUST
OFF THE SOUTHEAST COAST ON SUNDAY MORNING BEFORE MOVING NORTHEAST
AWAY FROM AREA ON SUNDAY NIGHT. OUR FORECAST INCREASED CLOUD
COVER ACROSS THE AREA FOR SATURDAY INTO EARLY MONDAY BUT GIVEN
MOST OF THE FORCING FOR ASCENT IS OFF THE COAST AND JUST ABOUT
EVERY MEMBER OF THE LATEST GFE AND EC ENSEMBLES NOTE NO
PRECIPITATION, WILL KEEP THE FORECAST DRY. A GENERALLY FAIR AND
DRY NORTHWEST FLOW IS EXPECTED FOR LATE SUNDAY INTO LATE
MONDAY. THERE IS A SIGNAL FOR PERTURBATIONS IN THE NORTHWEST AND
WESTERLY FLOW TO APPROACH OR MOVE INTO THE AREA FOR LATE
TUESDAY AND INTO WEDNESDAY. GUIDANCE IS ALL OF THE PLACE WITH
HOW THIS WILL SHAKE OUT BUT A HANDFUL OF GFS/EC ENSEMBLE MEMBERS
PRODUCING LIGHT PRECIPITATION FOR LATE TUESDAY AND WEDNESDAY.
GIVEN THE UNCERTAINTY WILL KEEP THE FORECAST DRY. TEMPERATURES
SHOULD GENERALLY MODERATE THROUGH THE PERIOD WITH HIGHS IN THE
40S TO NEAR 50 ON SATURDAY MODERATING INTO THE LOWER TO MID 50S
ON SUNDAY AND THE LOWER TO MID 60S ON TUESDAY. -BLAES
AVIATION /12Z WEDNESDAY THROUGH SUNDAY/
AS OF 700 AM WEDNESDAY...
LOW PRESSURE WILL STRENGTHEN AND TRACK ALONG AND JUST OFFSHORE THE
COAST OF THE CAROLINAS THROUGH TONIGHT; AND AS IT DOES SO,
PRECIPITATION AND FLIGHT RESTRICTIONS WILL EXPAND ACROSS CNTL NC.
ASSOCIATED VFR CONDITIONS AT THE START OF THE FORECAST PERIOD WILL
DETERIORATE TO MVFR, AND POTENTIALLY IFR ESPECIALLY AT ERN SITES,
FROM LATE THIS MORNING THROUGH AFTERNOON, THEN REMAIN SO THROUGH THE
END OF THE TAF PERIOD. THE PRECIPITATION TYPE AT INT/GSO SHOULD BE
ALL SNOW, WHILE A SNOW AND SLEET MIX WILL BE MORE LIKELY AT RDU AND
ESPECIALLY RWI. AFTER A SHORT PERIOD OF RAIN AT ONSET AT FAY, THE
PREDOMINANT P-TYPE THERE WILL BE FREEZING RAIN. ALTHOUGH FLIGHT
RESTRICTIONS WILL LIKELY BE RELATIVELY STEADY OVERNIGHT, THERE
REMAINS A CHANCE THAT PRECIPITATION MAY TAPER TO LIGHT FREEZING
RAIN/FREEZING DRIZZLE, WHEN LIFT WILL DIMINISH AND THE CLOUD LAYER
MAY BECOME DOMINATED BY SUPERCOOLED WATER VERSUS ICE.
OUTLOOK: LIGHT SNOW WILL PROBABLY REDEVELOP AND MAINTAIN FLIGHT
RESTRICTIONS WITH THE PASSAGE OF A VIGOROUS MID/UPR-LEVEL TROUGH
EARLY THU, BEFORE SKIES CLEAR TO VFR AND NWLY SURFACE WINDS
STRENGTHEN AND BECOME GUSTY DURING THE AFTERNOON.
RAH WATCHES/WARNINGS/ADVISORIES
WINTER STORM WARNING FROM 7 AM THIS MORNING TO 10 AM EST
THURSDAY FOR NCZ007>011-026>028-043-078.
WINTER WEATHER ADVISORY FROM 7 AM THIS MORNING TO 10 AM EST
THURSDAY FOR NCZ021>025-038>042-073>077-083>086-088-089.
SYNOPSIS...MWS
NEAR TERM...GREEN
SHORT TERM...BLAES
LONG TERM...BLAES
AVIATION...MWS/HELOCK
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