471
FXUS62 KRAH 172051
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
351 PM EST MON FEB 17 2025
SYNOPSIS
CONTINENTAL POLAR HIGH PRESSURE WILL BUILD ACROSS THE MIDDLE
ATLANTIC AND CAROLINAS THROUGH TUESDAY NIGHT. LOW PRESSURE WILL THEN
TRACK ACROSS THE GULF AND SOUTH ATLANTIC COASTS WEDNESDAY AND
WEDNESDAY NIGHT. ARCTIC HIGH PRESSURE WILL FOLLOW AND MIGRATE FROM
THE NORTHERN PLAINS TO THE MIDDLE ATLANTIC, WHILE WEAKENING AND
MODIFYING, THROUGH NEXT WEEKEND.
NEAR TERM /THROUGH TONIGHT/
AS OF 345 PM MONDAY...
THE 300 PM CONDITIONS ACROSS CENTRAL NC ARE IN THE MID 40S TO
50 DEGREES WITH NORTHWESTERLY GUSTS BETWEEN 15-25 KTS. HIGHS
THIS AFTERNOON SHOULD REACH THE MID 40S IN THE NORTH TO UPPER
40S TO 50 IN THE SOUTH. AS THE PRESSURE GRADIENT OVER THE REGION
CONTINUES TO WEAKEN THIS AFTERNOON AND EVENING, GUSTS SHOULD
DIMINISH. WINDS OVERNIGHT SHOULD BE LIGHT, VEERING TO A MORE
NORTHERLY DIRECTION. LOW TEMPERATURES OVERNIGHT SHOULD DIP INTO
THE MID 20S IN THE NORTH TO AROUND 30 DEGREES IN THE SOUTH.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/
AS OF 345 PM MONDAY...
* A WINTER WEATHER WATCH HAS BEEN ISSUED FOR WEDNESDAY MORNING
INTO THURSDAY MORNING FOR MOST OF CENTRAL NC.
* THE MOST HAZARDOUS TRAVEL CONDITIONS WILL LIKELY BE WEDNESDAY
AFTERNOON INTO THE OVERNIGHT HOURS.
A RESURGENCE OF COLD/DRY ARCTIC AIR WILL SPILL EAST OF THE NORTHERN
APPALACHIAN MOUNTAINS FROM THE PARENT HIGH OVER SOUTHERN
SASKATCHEWAN AND NORTHERN PLAINS LATE TUES INTO EARLY WED AND WILL
SET THE STAGE FOR OUR WINTER EVENT. HOW FAR SOUTH THIS BACKDOOR COLD
FRONT AND VERY LOW DEW POINTS (TEENS TO SINGLE DIGITS) IN ITS WAKE
PENETRATE INTO CENTRAL NC WED MORNING WILL BE VITAL GIVEN THE LACK
OF A FAVORABLE STRENGTH/LOCATION OF A PARENT HIGH TO OUR NORTH.
FROM A PATTERN RECOGNITION PERSPECTIVE, THE SYNOPTIC ENVIRONMENT
WILL BE DRIVEN BY INITIALLY A FLAT MID/UPPER LEVEL PATTERN WITH
DOMINANT LIFT COMING FROM JET DYNAMICS IN A FAVORABLE RIGHT-ENTRANCE
REGION OF A 140-160 KT 250MB JET AND STRENGTHENING SOUTHERLY WAA AT
850MB. AN INITIALLY WEAK SURFACE LOW WILL DEVELOP WED MORNING OVER
THE CENTRAL GULF COAST STATES AND TRACK ENE IN A MILLER A
CYCLOGENESIS PATTERN AND PHASE WITH A SHARPENING INVERTED TROUGH OFF
THE CAROLINA COAST THROUGH THURS MORNING. THIS PATTERN WILL MOST
LIKELY RESULT IN BROAD TRANSITION ZONES OF PRECIPITATION TYPES
BETWEEN SNOW, SLEET, FREEZING RAIN, AND RAIN WED MORNING. THIS
TRANSITION ZONE WILL LIKELY LIFT NORTH THROUGH THE DAY, STALL
SOMEWHERE OVER THE PIEDMONT, AND THEN COLLAPSE BACK SOUTH AND
EAST WED NIGHT INTO EARLY THURS AS THE SURFACE LOW OFFSHORE DEEPENS.
CHANGES FROM PREVIOUS FORECAST HAVE A SUBTLE SHIFT FARTHER SOUTH IN
THIS TRANSITION ZONE GIVEN THE SLIGHTLY DEEPER SURFACE LOW AND
COLDER AIR FARTHER SOUTH IN NC. OVERALL THE MAGNITUDES OF SNOW AND
ICE ACCUMULATION HAVE REMAINED RELATIVELY THE SAME (1 TO 6
INCHES OF SNOW AND SLEET ACCUMULATION, GREATEST TOWARDS THE
NORTHERN PIEDMONT AND NORTHERN COASTAL PLAIN. ICE ACCUMULATION
RANGE FROM A TENTH UP TO A THIRD OF AN INCH). THESE AMOUNTS
WILL LIKELY RESULT IN HAZARDOUS TRAVEL CONDITIONS ACROSS THE
WATCH AREA WITH SCATTERED TO NUMEROUS POWER OUTAGES POSSIBLE
WHERE THE GREATEST ICE ACCUMULATION OCCURS.
THE EVENTUAL SCENARIO THAT UNFOLDS WILL BE VERY SUSCEPTIBLE TO MINOR
CHANGES IN THE SYNOPTIC AND MESOSCALE PATTERN AND TIMEFRAME
BETWEEN NOW AND WED MORNING, SO EXPECT CONTINUED TWEAKS TO THE
FORECAST AS FORECAST CONFIDENCE INCREASES.
HIGH TEMPERATURES ON WED WILL LIKELY OCCUR EARLY WED MORNING AHEAD
OF PRECIPITATION MOVING IN WITH SURFACE TEMPERATURES DROPPING AS THE
OVERALL THERMO-PROFILE SATURATES TOWARDS THE WETBULB TEMPERATURE.
OVERNIGHT LOWS WILL BE WELL BELOW NORMAL AND RANGE FROM THE LOW TO
MID 20S WITH NEAR TEENS ACROSS THE NORTHERN PIEDMONT.
LONG TERM /THURSDAY THROUGH MONDAY/
AS OF 345 PM MONDAY...
* LINGERING LIGHT SNOW SHOWERS POSSIBLE THU MORNING WITH A FAST
MOVING VORT MAX OVERHEAD. ONLY MINOR ACCUMULATIONS EXPECTED
* WELL BELOW NORMAL TEMPERATURES THU TO SAT, WITH POSSIBLE COLD
ADVISORY CRITERIA THU NIGHT
* MODERATING TEMPERATURES OVER THE WEEKEND, WITH 50S FAVORED SUN
INTO MON
THE WINTER STORM FROM WED WILL BE LIFTING EAST AND NORTHEAST OF THE
REGION, BUT A STRONG MID-LEVEL VORT MAX WILL TRACK ACROSS NC/VA IN
THE MORNING AND AFTERNOON. STRONG HEIGHT FALLS WILL OVERSPREAD
CENTRAL AND NORTHERN PORTIONS OF CENTRAL NC. WHILE THE GREATEST LIFT
WILL BE UP IN VA, THE GFS SHOWS ENOUGH SATURATION IN THE DENDRITIC
GROWTH ZONE TO WARRANT SOME QUICK HITTING SNOW SHOWERS ALONG AND
NORTH OF US-64 FROM WEST TO EAST IN THE MORNING. GLOBAL ENSEMBLES
ALSO SHOW THIS, WITH THE 12Z ECMWF PROBABLY THE FURTHEST SOUTH WITH
THE ENERGY. AN ADDITIONAL LIGHT DUSTING OR MINOR ACCUMULATION OF
SNOW IS POSSIBLE, MAINLY OVER THE NORTHEAST PIEDMONT AND NORTHERN
COASTAL PLAIN. OTHERWISE, IT WILL BE COLD WITH HIGHS 20-25 DEGREES
BELOW AVERAGE IN THE LOW TO MID 30S. NORTHWEST WINDS GUSTING TO 25-
30 MPH WITH THE TIGHT GRADIENT STILL IN PLACE WITH THE DEPARTING LOW
AND ARCTIC HIGH OVER THE PLAINS WILL PRODUCE WIND CHILLS IN THE
TEENS AND LOW 20S. THERE MAY ALSO BE SOME BLOWING AND DRIFTING OF
SNOW. THE ARCTIC HIGH BUILDS INTO THE MS VALLEY BY EARLY FRI, AND
LOW TEMPERATURES DIP WELL BELOW NORMAL IN THE MID TO UPPER TEENS
UNDER FRESH SNOW COVER AND CLEAR SKIES. WE MAY REACH COLD ADVISORY
CRITERIA OVERNIGHT INTO FRI WITH APPARENT TEMPERATURES PROGGED TO BE
IN THE SINGLE DIGITS TO LOW TEENS.
THE EXTENDED REMAINS COLD AND WELL BELOW NORMAL INTO SAT WITH HIGHS
FRI IN THE MID 30S TO LOW 40S AND LOWS FRI NIGHT IN THE TEENS AND
LOW 20S. THE ARCTIC HIGH WILL BUILD INTO THE SOUTHERN APPALACHIANS
BY SAT, THEN MOVE OFFSHORE AND MODERATE LATE SAT INTO MON. THIS WILL
FAVOR A RETURN FLOW BY SUN, WITH MODERATING HIGHS SUN AND MON IN THE
50S. ALOFT, A WEST TO NORTHWEST FLOW WITH EMBEDDED SHORTWAVES WILL
BE IN PLACE INTO EARLY NEXT WEEK. SOME GUIDANCE INDICATES A CHANCE
OF RAIN SUN AND MON, MOST NOTABLY THE GFS WITH A SOUTHERN TRACK
SYSTEM IN THE TN VALLEY. BUT OTHER GUIDANCE AND ENSEMBLES ARE DRY IN
NW FLOW. HAVE KEPT THE EXTENDED DRY UNTIL BETTER AGREEMENT CAN BE
REACHED.
AVIATION /18Z MONDAY THROUGH SATURDAY/
AS OF 1235 PM MONDAY...
CONDITIONS WILL BE VFR FOR THE 24 HOUR TAF PERIOD. WINDS THIS
AFTERNOON WILL GUST UP TO 20 KTS FROM THE NORTHWEST. GUSTS SHOULD
DIMINISH THROUGHOUT THE EVENING AND WINDS OVERNIGHT WILL BE LIGHT,
POTENTIALLY COMPLETELY CALM IN SOME LOCATIONS. A FEW UPPER LEVEL
CLOUDS ARE EXPECTED THROUGHOUT THE DAY TODAY, BEFORE THICKENING NEAR
THE END OF THE TAF PERIOD.
OUTLOOK: TUESDAY SHOULD CONTINUE TO BE VFR. SUB-VFR CONDITIONS ARE
EXPECTED TO RETURN WEDNESDAY AS A POTENTIAL WINTRY EVENT IS LIKELY
TO IMPACT THE REGION. WITH THIS SYSTEM, ALL PRECIPITATION TYPES
(SNOW, SLEET, FREEZING RAIN, AND RAIN) ARE POSSIBLE THROUGHOUT THE
CWA. WE SHOULD RETURN TO VFR CONDITIONS BY THURSDAY NIGHT FOR THE
REST OF THE PERIOD.
RAH WATCHES/WARNINGS/ADVISORIES
WINTER STORM WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY
MORNING FOR NCZ007>011-021>028-038>043-075>078-085-086-088-089.
SYNOPSIS...MWS
NEAR TERM...HELOCK
SHORT TERM...SWIGGETT
LONG TERM...KREN
AVIATION...HELOCK
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