723
FXUS62 KRAH 190753
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
253 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 335 PM TUESDAY...
* NO CHANGE IN THE WINTER STORM WARNING AND ADVISORY AREAS FOR
WEDNESDAY INTO THURSDAY MORNING WITH THE AFTERNOON FORECAST UPDATE
DUE TO LOWER THAN NORMAL FORECAST CONFIDENCE.
* GREATEST TRAVEL IMPACTS AND POTENTIAL POWER OUTAGES WILL MOST
LIKELY OCCUR WEDNESDAY AFTERNOON INTO THE EARLY OVERNIGHT PERIOD.
* LINGERING SNOW SHOWERS THURSDAY MORNING WILL MOVE EAST AHEAD OF A
COLD FRONT WITH BREEZY WIND GUSTS OF 25 TO 35 MPH IN ITS WAKE.
THE OVERALL PATTERN CONSISTS OF A BACKDOOR COLD FRONT AND RESURGENCE
OF COLD/DRY ARCTIC AIR AHEAD THE ONSET OF WINTRY PRECIPITATION WED.
LIGHT PRECIPITATION WILL LIKELY BEGIN TO FALL AROUND 10 AM TOWARDS
THE SC/NC BORDER AND WILL RAPIDLY FILL ACROSS THE AREA INTO THE
EARLY AFTERNOON AS MID/UPPER FORCING FROM THE STRENGTHENING JET
STREAK MOVES OVERHEAD. THE BEST OVERLAP OF SYNOPTIC FORCING AND
INCREASING PRECIPITATION RATES WILL BE OVER THE EASTERN PIEDMONT AND
COASTAL PLAIN WED AFTERNOON TO AROUND 10 PM.
GIVEN THE LACK OF A FAVORABLE AND ANCHORED SURFACE HIGH LOCATION,
THE PREEXISTING ENVIRONMENT DEPOSITED BY THE BACKDOOR FRONT WILL
LIKELY DRIVE THE INITIAL ONSET P-TYPE DISTRIBUTION. CURRENT FORECAST
HIGHLIGHTS A VERY BROAD TRANSITION ZONE CENTERED AROUND US-64 WHERE
SNOW, SLEET, FREEZING RAIN/OR RAIN, WITH PREDOMINANTLY SNOW NORTH OF
THIS ZONE AND INITIALLY LIGHT RAIN TO ITS SOUTH. AS PRECIP RATES
INCREASE THROUGH THE AFTERNOON, SURFACE TEMPERATURES ARE EXPECTED TO
DROP BELOW FREEZING TOWARDS THE SURFACE WETBULB AND RESULT IN AN
EXPANDING AREA OF FREEZING RAIN OVER THE SANDHILLS AND INTO THE
SOUTHERN/CENTRAL COASTAL PLAIN. AT THE SAME TIME, STRENGTHENING
SOUTHERLY WAA ALOFT WILL BEGIN TO LIFT THIS TRANSITION ZONE FARTHER
NORTH, BUT WHERE ITS STALLS IS VERY UNCERTAIN. LATEST FORECAST
TRENDED TOWARDS WARMER/STRONGER WAA SOLUTIONS THAT TYPICALLY VERIFY
CLOSER WELL IN THESE SCENARIOS. THIS BRINGS THE SNOW/SLEET LINE TO
AROUND THE I-85 CORRIDOR INTO THE NORTHERN COASTAL PLAIN BEFORE
COLLAPSING BACK SOUTH OVERNIGHT.
OVERALL PRECIP DISTRIBUTION WILL BEGIN TO SPREAD EASTWARD AND
DECREASE IN INTENSITY AS DRY AIR ALOFT BEGINS TO SPREAD OVERHEAD
LATE WED INTO EARLY THURS. VERY LIGHT FREEZING DRIZZLE AND SPORADIC
SLEET WILL LIKELY BE THE PREDOMINANT P-TYPES DURING THIS TIME AS WE
LOSE SATURATION IN THE DGZ. SNOW ACCUMULATIONS WILL LIKELY BE
GREATEST NORTH OF US-64 AND RANGE FROM 1 TO 5 INCHES, LOCALLY HIGHER
AMOUNTS POSSIBLE TOWARDS THE VA/NC BORDER. ICE ACCUMULATIONS WILL BE
GREATEST SOUTH OF US-64 IN THE COASTAL PLAIN WITH TOTALS RANGING
FROM 0.05" TO AROUND 0.25". A COMBINATION OF SNOW, SLEET, AND
FREEZING RAIN IN THE ADVISORY AREAS MAY RESULT IN MINOR IMPACTS TO
TRAVEL AND WARRANT THE CONTINUATION OF THE ADVISORY AT THIS TIME.
A BRIEF LULL EARLY THURS MORNING WILL FILL BACK IN TOWARDS SUNRISE
AS A POTENT UPPER LOW AND STRONG FORCING OVERSPREADS THE AREA
THROUGH EARLY AFTERNOON. POINT SOUNDINGS SUGGEST STEEPENING LAPSE
RATES AND SATURATION RETURNING TO THE DGZ TO RESULT IN THE POTENTIAL
FOR SCATTERED SNOW SHOWERS. OVERALL ACCUMULATIONS ARE LIGHT AND
MINIMAL TO NO ACCUMULATIONS ARE EXPECTED. THURS AFTERNOON A STRONG
COLD FRONT WILL BEGIN TO MOVE ACROSS THE REGION FROM WEST TO EAST
AND RESULT IN STRONG WIND GUSTS OF 25 TO 35 MPH BEFORE DIMINISHING A
FEW HOURS AFTER SUNSET, ALTHOUGH CONTINUED CAA MAY CONTINUE SOME
GUSTINESS THROUGH THE EVENING.
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 /08Z WEDNESDAY THROUGH SUNDAY/
AS OF 125 AM WEDNESDAY...
INITIALLY VFR CONDITIONS WILL DETERIORATE TO MVFR AND POTENTIALLY
IFR WEDNESDAY LATE MORNING THROUGH AFTERNOON, THEN REMAIN SO THROUGH
THE END OF THE TAF PERIOD, AS LOW PRESSURE GATHERS STRENGTH OFF THE
COAST OF THE CAROLINAS AND PRECIPITATION OVERSPREADS THE REGION.
ADDITIONALLY, LIGHT NELY SURFACE WINDS EARLY THIS MORNING WILL
STRENGTHEN AND BECOME AT LEAST OCCASIONALLY GUSTY WITH THE PASSAGE
OF A BACKDOOR COLD FRONT FROM NORTHEAST TO SOUTHWEST BETWEEN ~10-
15Z, PRIOR TO THE ONSET OF PRECIPITATION AND FLIGHT RESTRICTIONS.
WITH RESPECT TO PRECIPITATION TYPES, ALL WILL BE POSSIBLE OVER
CENTRAL NC, INCLUDING ALL OR MAINLY SNOW OVER THE PIEDMONT
(RDU/GSO/INT), MAINLY FREEZING RAIN AT FAY, AND A MIX OF SNOW,
SLEET, AND FREEZING RAIN AT RWI. NEAR THE END OF THE TAF PERIOD, ALL
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: MVFR/POTENTIAL IFR CONDITIONS SHOULD CONTINUE WED NIGHT-THU
MORNING. LIGHT SNOW WILL PROBABLY REDEVELOP WITH THE PASSAGE OF A
VIGOROUS MID/UPR-LEVEL TROUGH EARLY THU, BEFORE SKIES CLEAR 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...SWIGGETT
SHORT TERM...BLAES
LONG TERM...BLAES
AVIATION...MWS
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page