360
FXUS62 KRAH 170803
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
300 AM 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 /TONIGHT THROUGH TUESDAY NIGHT/
AS OF 950 PM SUNDAY...
*SEASONABLY CHILLY, AND CONTINUED BLUSTERY THROUGH THE EARLY MORNING
HOURS MON.
IN THE WAKE OF A VIGOROUS SHORTWAVE TROUGH NOW PIVOTING ACROSS THE
NORTHEAST, AND A MINOR TRAILING ONE THAT WILL PIVOT ACROSS AND
OFFSHORE THE SRN MIDDLE ATLANTIC TONIGHT, QUASI-ZONAL FLOW AND
RISING HEIGHTS WILL DEVELOP FROM THE SRN AND CNTL PLAINS TO THE SRN
MIDDLE ATLANTIC THROUGH EARLY MON. THOSE RISING HEIGHTS ALOFT WILL
BE ACCOMPANIED BY CONTINUED, STRONG LOW/MID-TROPOSPHERIC COLD AIR
ADVECTION OVER THE MIDDLE AND SOUTH ATLANTIC. DEEP SUBSIDENCE WILL
RESULT OVER CNTL NC.
AT THE SURFACE, THE POLAR FRONT HAS CROSSED ALL BUT THE SRN AND CNTL
OUTER BANKS IN NC AS OF 02Z, WITH FOLLOWING PRESSURE RISES AND HIGH
PRESSURE THAT WILL CONTINUE TO BUILD FROM THE CNTL PLAINS AND MID MS
VALLEY SEWD AND ACROSS THE SOUTHEAST TONIGHT. WHILE CAA AND MIXING
WILL PROBABLY PERSIST THROUGHOUT THE NIGHT, POINT FORECAST SOUNDINGS
AND MOMENTUM TRANSFER POTENTIAL INDICATE THE STRONGEST MIXING AND
ONGOING GUSTS BETWEEN 25-35 MPH LATE THIS EVENING WILL GRADUALLY
LESSEN AFTER 05-06Z. PREVIOUSLY FORECAST LOW TEMPERATURES GENERALLY
WITHIN A FEW DEGREES EITHER SIDE OF 30 F REMAIN ON TRACK.
MON/MON NIGHT: BROAD, FAST ZONAL STEERING FLOW WILL PERSIST, AS VAST
SURFACE HIGH PRESSURE CENTERED OVER SASKATCHEWAN SPREADS SE INTO NC.
DRY AND STABLE AIR THROUGH A DEEP LAYER WILL KEEP SKIES FAIR TO
MOSTLY SUNNY MON, ALTHOUGH BY MON NIGHT WELL START TO SEE HIGH
CLOUDS SPREADING IN FROM THE WYOMING BASIN/N ROCKIES AND CENTRAL
PLAINS, ESP ACROSS OUR N, AND SKIES HERE SHOULD TREND TO PARTLY
CLOUDY. LOW LEVEL THICKNESSES WILL BE AROUND 35 M BELOW NORMAL, THUS
EXPECT BELOW NORMAL HIGHS IN THE MID 40S TO LOW 50S, FOLLOWED BY
LOWS IN THE MID 20S TO AROUND 30. -GIH
TUE/TUE NIGHT: THE MID-LEVEL FLOW TUESDAY WILL START OFF ZONAL
BEFORE A WEAKLY AMPLIFIED RIDGE DEVELOPS OVER CENTRAL NC TUESDAY
EVENING. A STRONG HIGH OVER THE UPPER MIDWEST WILL EXTEND COOL NELY
FLOW ACROSS OUR AREA. HIGH CLOUDS AND CHILLY TEMPS IN THE UPPER 40S
TO LOWER 50S IS EXPECTED WITH DRY CONDITIONS. THE MID-LEVEL RIDGE
WILL DE-AMPLIFY AS A STRONG TROUGH DIGS INTO THE UPPER MIDWEST
OVERNIGHT. ANY PRECIPITATION SHOULD GENERALLY HOLD OFF THROUGH 12Z
WEDNESDAY. OVERNIGHT LOWS IN THE UPPER 20S TO LOWER TO MID 30S IS
EXPECTED.
SHORT TERM /WEDNESDAY THROUGH THURSDAY/
AS OF 300 AM MONDAY...
LOW PRESSURE WILL BE CENTERED NEAR NEW ORLEANS AS OF WEDNESDAY
MORNING, MOVE OVER FLORIDA WEDNESDAY AFTERNOON, THEN MOVE NORTHEAST
ALONG THE COASTLINE OF THE CAROLINAS WEDNESDAY NIGHT INTO THURSDAY
MORNING. OVERALL, PERHAPS THE GREATEST CHANGE WITH THE 00Z GUIDANCE
IS THAT LIQUID PRECIPITATION TOTALS HAVE COME DOWN FROM THE 12Z
GUIDANCE. THIS IS LIKELY RELATED TO THE 00Z ECMWF SHOWING THE
SURFACE LOW 5-10 MB WEAKER THAN THE 12Z RUN, ALTHOUGH THE 00Z GFS
DOES NOT SHOW MUCH DIFFERENCE WITH THE STRENGTH OF THE LOW COMPARED
TO THE 18Z RUN. THE OFFICIAL QPF IS ABOUT HALF AS MUCH IN THE TRIAD
AS BEFORE, WITH A SMALLER REDUCTION FARTHER TO THE EAST.
THERE IS STILL A GREAT DEAL OF UNCERTAINTY AS TO PRECIPITATION TYPE.
ALL PRECIPITATION TYPES ARE EXPECTED TO OCCUR SOMEWHERE ACROSS THE
FORECAST AREA. COMPARED TO THE PREVIOUS FORECAST, ONE PRIMARY CHANGE
IS THAT THE WARM NOSE APPEARS STRONG ENOUGH TO PRODUCE A LARGER AREA
OF SLEET ALONG AND SOUTH OF US-64 TO THE WEST OF I-40 ON WEDNESDAY.
THE OTHER PRIMARY CHANGE IS THAT THE CHANCE FOR FREEZING RAIN IS
STILL INITIALLY ALONG AND SOUTH OF US-64 WEDNESDAY MORNING, BUT THEN
THAT AREA GREATLY EXPANDS TO THE SOUTH AND NORTHEAST IN THE LATE
AFTERNOON AND EVENING. THE MODEL TREND WAS TO BRING SURFACE
TEMPERATURES DOWN SLIGHTLY, WHICH EXPANDS THE AREA THAT COULD
RECEIVE FREEZING RAIN INSTEAD OF LIQUID RAIN. IT STILL APPEARS THAT
PRECIPITATION WILL BE MAKING ITS WAY INTO THE REGION FROM SOUTHWEST
TO NORTHEAST WEDNESDAY MORNING, WITH WIDESPREAD PRECIPITATION
WEDNESDAY AFTERNOON, THEN PRECIPITATION SHOULD BEGIN WINDING DOWN
FROM SOUTHWEST TO NORTHEAST WEDNESDAY NIGHT, WITH PERHAPS A STRAY
FLURRY POSSIBLE THURSDAY MORNING ACROSS THE NORTHEAST.
THE OFFICIAL SNOW/ICE FORECASTS NOW GO THROUGH THURSDAY MORNING, AND
SHOULD COVER ALL ACCUMULATING PRECIPITATION. THE SPECIFICS OF THOSE
TOTALS ARE LIKELY TO CHANGE CONSIDERING THE UNCERTAINTY IN REGARD TO
PRECIPITATION TYPE, BUT IT APPEARS THAT EXCEPT FOR SOUTHERN TIER
COUNTIES, ALL AREAS ARE LIKELY TO RECEIVE AT LEAST SOME ACCUMULATING
SNOW, WITH THE HIGHEST TOTALS NORTH AND EAST OF THE TRIANGLE
COINCIDENT WITH THE HIGHEST QPF. IT ALSO APPEARS THAT NEARLY ALL
LOCATIONS WILL RECEIVE AT LEAST SOME ACCUMULATING FREEZING RAIN,
WITH THE EXCEPTION OF THE TRIAD AND NORTHERN PERSON/VANCE COUNTIES
WHERE NO ICE ACCUMULATION IS FORECAST, AND THE HIGHEST ICE TOTALS
ARE CURRENTLY IN JOHNSTON/WILSON/WAYNE COUNTIES. ALTHOUGH SOME
LOCATIONS HAVE THE POTENTIAL TO REACH WARNING CRITERIA FOR EITHER
SNOW OR ICE, THERE IS NOT ENOUGH CONFIDENCE IN THOSE VALUES DUE TO
THE UNCERTAINTY IN PRECIPITATION TYPES, AND A WINTER STORM WATCH
WILL NOT BE ISSUED ON THIS SHIFT.
LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/
AS OF 100 AM MONDAY...
THE ARCTIC HIGH WILL BUILD DOWN INTO THE CENTRAL PLAINS AND MID-MS
VALLEY ON THURSDAY NIGHT AND FRIDAY, THEN THE TN VALLEY ON SATURDAY
AND THE EAST COAST ON SUNDAY. THIS WILL BRING A VERY COLD AND DRY
AIR MASS WHICH GRADUALLY MODIFIES THROUGH THE END OF THE PERIOD.
TEMPERATURES, JUST HOW COLD IT GETS, WILL NOT BE DETERMINED UNTIL
THE POTENTIAL FOR THE WINTER STORM IS OVER. WE WILL KEEP THE
PREVIOUS FORECAST OF THURSDAY NIGHT LOWS IN THE TEENS TO LOWER 20S.
FRIDAY'S FORECAST HIGHS ONLY IN THE UPPER 30S TO LOWER 40S, THEN
40S ON SATURDAY AND SUNDAY.
AVIATION /06Z MONDAY THROUGH FRIDAY/
AS OF 100 AM MONDAY...
VFR CONDITIONS ARE EXPECTED THROUGH 06Z/TUE.
OUTLOOK: POTENTIAL LOW PRESSURE MAY BRING A CHANCE OF WINTRY
PRECIPITATION AND FLIGHT RESTRICTIONS TO CNTL NC LATE TUE NIGHT
THROUGH WED. OTHERWISE, VFR.
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...MWS
NEAR TERM...MWS/HARTFIELD/LUCHETTI
SHORT TERM...GREEN
LONG TERM...BADGETT
AVIATION...BADGETT/MWS
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