561
FXUS62 KRAH 181914
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
215 PM EST TUE FEB 18 2025
SYNOPSIS
CONTINENTAL POLAR HIGH PRESSURE WILL BUILD ACROSS THE MIDDLE
ATLANTIC AND CAROLINAS THROUGH TONIGHT. LOW PRESSURE WILL 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 215 PM TUESDAY...
THE AFTERNOON SURFACE ANALYSIS REVEALS A COLD FRONT STRETCHING FROM
NORTHERN MS/AL INTO FAR EASTERN PORTIONS OF TN. ANOTHER BRANCH OF
THE FRONT EXTENDS ACROSS FAR EASTERN WV AND NORTHERN VA, WITH SINGLE
DIGIT DEWPOINTS ON THE NORTH SIDE OF THE FRONT. ALOFT, WATER VAPOR
SHOWS A TROUGH NEAR THE FOUR CORNERS THAT WILL BECOME AN OPEN WAVE
AS IT REACHES THE TN VALLEY AND SE US OVERNIGHT INTO TOMORROW
MORNING. THIS WAVE WILL BE AIDED BY ANOTHER SHORTWAVE TROUGH DIGGING
OUT OF MT INTO THE CENTRAL PLAINS. WITH TIME, GUIDANCE SHOWS THE
FRONT OVER VA SLIDING SOUTHWESTWARD IN A BACKDOOR FASHION OVERNIGHT
AS WEAK RIDGING SETS UP OVER THE MID-ATLANTIC. GUIDANCE APPEARS A
LITTLE FASTER WITH THE BACKDOOR FRONT, SUGGESTING LOWS IN THE MID
20S IN THE NORTH AND LOW 30S IN THE SOUTH. HOWEVER, GUIDANCE
SOMETIMES STRUGGLES WITH THE COLD AIR, BRINGING IT IN TOO FAST
ACROSS THE MOUNTAINS OF VA. WITH THAT, WE DID NOT GO AS LOW AS THE
MET WOULD SUGGEST, BUT HAVE LOWS MID/UPPER 20S IN THE NORTH AND
LOWER 30S IN THE FAR SOUTH. MOST OF THE WINTRY PRECIPITATION SHOULD
HOLD OFF UNTIL AFTER DAYBREAK WED, BUT INCREASING LOW-LEVEL WAA
AHEAD OF THE DEVELOPING SURFACE LOW COULD WARRANT LOW-END SNOW
CHANCES IN THE FAR NORTHWEST NEAR 12Z WED.
SHORT TERM /WEDNESDAY THROUGH THURSDAY/
AS OF 330 AM TUESDAY...
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, FEEL THAT THERE WERE SOME MINOR TWEAKS MADE TO THE
FORECAST, BUT NO MAJOR CHANGES WERE SEEN WITH THE 00Z MODEL
GUIDANCE. PRECIPITATION DOES APPEAR THAT IT WILL BE SOMEWHAT SLOWER
TO ARRIVE WEDNESDAY MORNING, BUT SHOULD ARRIVE FROM BOTH THE WEST
AND SOUTH. WEDNESDAY AFTERNOON SHOULD STILL BE THE PERIOD WITH THE
GREATEST PRECIPITATION AMOUNTS IN NEARLY ALL LOCATIONS,
PRECIPITATION WILL TREND DOWNWARD WEDNESDAY EVENING, AND
ACCUMULATION SHOULD BE MINIMAL OVERNIGHT WEDNESDAY. ONE WRINKLE IS
THAT THE GFS AND ECMWF ARE BOTH SHOWING SOME ADDITIONAL LIGHT
SNOWFALL BEHIND THE PRIMARY SYSTEM THURSDAY MORNING, CONTINUING THE
TREND FIRST NOTED BY THE DAY SHIFT.
CONFIDENCE REMAINS HIGH THAT IN ALL COUNTIES ALONG THE VIRGINIA
BORDER, SNOW WILL BE THE ONLY PRECIPITATION TYPE. HOWEVER, ANYWHERE
SOUTH OF THAT, CONFIDENCE REMAINS LOW IN THE EVOLUTION OF
PRECIPITATION TYPES. FOR EXAMPLE, THE 00Z GFS SUGGESTS ALL SNOW AT
RDU, WHILE THE 00Z NAM BEGINS WITH A SHORT PERIOD OF SNOW, QUICKLY
TRANSITIONS TO AN EXTENDED PERIOD OF SLEET, THEN EVENTUALLY CHANGES
BACK TO SNOW. NEEDLESS TO SAY, THIS HAS MAJOR IMPACTS ON
ACCUMULATION TOTALS. IN ADDITION, MODELS HAVE HAD A SLIGHT DOWNWARD
TREND IN LIQUID PRECIPITATION TOTALS. THAT CERTAINLY DOESN'T MEAN
THAT THIS WILL TURN INTO A NON-EVENT, BUT DEPENDING ON THE
PARTICULAR TIMING OF WHEN LESS PRECIPITATION OCCURS, IT COULD
PREVENT WARNING CRITERIA FROM BEING REACHED. A LARGE SWATH OF THE
FORECAST AREA WILL HAVE AT LEAST SOME ICE ACCUMULATION, BUT THERE
HAS BEEN A VERY MINIMAL AREA THAT HAS SHOWN 1/4 INCH ICE
ACCUMULATION, AND THIS AREA CONTINUES TO SHIFT A LITTLE BIT BETWEEN
MODEL RUNS. LIQUID RAIN IS NOT EXPECTED TO REACH TOO MUCH FARTHER
NORTH THAN JOHNSTON AND WAYNE COUNTIES. ALONG THE US-64 CORRIDOR,
SNOW, SLEET, AND FREEZING RAIN ARE ALL EXPECTED AT SOME POINT.
CONSIDERING MODELS HAVE BEEN CONSISTENT IN SHOWING MODERATE/HEAVY
SNOW ALONG THE VA/NC LINE DURING A PERIOD WITH HIGH QPF, IN
COLLABORATION WITH NEIGHBORS, HAVE DECIDED TO GO AHEAD AND ISSUE A
WINTER STORM WARNING ALONG THE VA/NC BORDER. AN ADDITIONAL AREA
INCLUDING EDGECOMBE, WILSON, AND WAYNE COUNTIES WAS ALSO UPGRADED TO
A WINTER STORM WARNING DUE TO A COMBINATION OF SNOW, SLEET, AND
FREEZING RAIN. HOWEVER, CONFIDENCE IN SNOW VS ICE TOTALS IS NOT HIGH
ENOUGH TO WARRANT AN UPGRADE FROM WATCH TO WARNING IN OTHER
LOCATIONS, AND WILL MAINTAIN THE WINTER STORM WATCH THAT IS
CURRENTLY IN EFFECT ELSEWHERE. THE HOPE IS THAT ANOTHER SET OF MODEL
RUNS WILL RESULT IN GREATER CONFIDENCE AS TO WHERE WARNING CRITERIA
WILL BE REACHED, LIKELY AS A COMBINATION OF BOTH SNOW AND ICE. MOST,
BUT NOT ALL, OF THE REMAINING WINTER STORM WATCH COUNTIES ARE
FORECAST TO HAVE AT LEAST SOME ACCUMULATING FREEZING RAIN, WHICH
WOULD NECESSITATE AT LEAST A WINTER WEATHER ADVISORY.
DAYTIME HIGHS WEDNESDAY 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 WEDNESDAY NIGHT WILL BE IN THE LOW
TO MID 20S. HIGHS THURSDAY WILL BE IN THE 30S. WIND CHILLS WILL BE
IN THE 20S EACH DAY - ON WEDNESDAY MORESO BECAUSE OF THE LOWER
TEMPERATURES, ON THURSDAY MORE BECAUSE OF HIGHER WIND GUSTS AS
SPRAWLING HIGH PRESSURE BEGINS TO BUILD IN TO THE CENTRAL
UNITED STATES BEHIND THE DEPARTING LOW.
LONG TERM /THURSDAY NIGHT THROUGH MONDAY/
AS OF 229 AM TUESDAY...
VERY COLD THURSDAY NIGHT THROUGH SATURDAY MORNING, MODERATING
TEMPERATURES EXPECTED THIS WEEKEND.
WE MAY REACH COLD ADVISORY CRITERIA THURSDAY NIGHT INTO FRIDAY
MORNING WITH APPARENT TEMPERATURES EXPECTED TO BE IN THE SINGLE
DIGITS TO AROUND 12 DEGREES COURTESY OF THE COLD ARCTIC HIGH
PRESSURE DOMINATING THE REGION. LOWS THURSDAY NIGHT SHOULD BE IN THE
TEENS TO LOWER 20S SOUTH. HIGHS FRIDAY SHOULD BE IN THE MID 30S TO
MID 40S NORTH TO SOUTH. LOWS FRIDAY NIGHT 12-22.
SATURDAY HIGHS WILL MODERATE WITH CONTINUED MAINLY SUNNY WEATHER AS
THE HIGH PRESSURE MOVES OVERNIGHT. TEMPERATURES SHOULD REACH THE
40S. EXPECT MODERATING TEMPERATURES INTO THE UPPER 40S AND LOWER 50S
SUNDAY, AND HIGHS BY MONDAY INTO THE 50S. DRY WEATHER IS CURRENTLY
FORECAST.
AVIATION /18Z TUESDAY THROUGH SUNDAY/
AS OF 1215 PM TUESDAY...
THERE IS HIGH CONFIDENCE THAT VFR CONDITIONS WILL START THE TAF
PERIOD. ONLY BROKEN TO OVERCAST MID/HIGH CLOUDS ARE EXPECTED INTO
THE EARLY MORNING HOURS OF WED. GUIDANCE IS IN FAIRLY GOOD AGREEMENT
ON WINTRY PRECIPITATION SPREADING ACROSS THE TERMINALS WED MORNING,
ROUGHLY BETWEEN 13 AND 15Z, EARLIEST AT FAY. AS FOR PRECIPITATION
TYPES, FORECAST SOUNDINGS FROM A SUITE OF MODEL DATA SUGGESTS MAINLY
SNOW AT GSO/INT, A MIXTURE OF SNOW AND SLEET AT RDU/RWI, AND MAINLY
LIGHT RAIN TRANSITIONING TO FZRA AT FAY. MVFR CONDITIONS ARE
EXPECTED IN THIS WINTRY WEATHER, WITH A GOOD PROBABILITY OF IFR
TOWARDS THE TAIL END OF THE TAF PERIOD. NORTHEASTERLY WINDS WILL
GUST AT TIMES TO 18-22 KT WED MORNING INTO THE AFTERNOON AS THE
PRESSURE GRADIENT TIGHTENS.
OUTLOOK: IFR CONDITIONS IN A WINTRY MIX OF SNOW, SLEET, AND FREEZING
RAIN IS EXPECTED ACROSS THE TERMINALS WED INTO THU. LIGHT SNOW IS
MOST FAVORED AT GSO/INT, WITH A MIXTURE OF SNOW AND SLEET AT
RDU/RWI, AND MAINLY FZRA AT FAY. A SHORT PERIOD OF LIGHT SNOW IS
POSSIBLE ACROSS ALL TERMINALS THU MORNING BEFORE PRECIPITATION ENDS
MIDDAY THU. VFR RETURNS THU AFTERNOON AND CONTINUES THROUGH THE
REMAINDER OF THE PERIOD.
RAH WATCHES/WARNINGS/ADVISORIES
WINTER STORM WARNING FROM 7 AM WEDNESDAY TO 10 AM EST THURSDAY FOR
NCZ007>011-026>028-043-078.
WINTER WEATHER ADVISORY FROM 7 AM WEDNESDAY TO 10 AM EST THURSDAY
FOR NCZ021>025-038>042-073>077-083>086-088-089.
SYNOPSIS...KREN/MWS
NEAR TERM...KREN
SHORT TERM...GREEN
LONG TERM...BADGETT
AVIATION...KREN
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