365
FOUS11 KWBC 212014
QPFHSD
PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
314 PM EST SAT FEB 21 2026
VALID 00Z SUN FEB 22 2026 - 00Z WED FEB 25 2026
..NORTHEAST AND MID ATLANTIC
DAYS 2-3...
*** NOR'EASTER DEVELOPS NEAR THE MID-ATLANTIC COAST SUNDAY WITH
HEAVY SNOW AND BLIZZARD CONDITIONS FOR AT LEAST COASTAL AREAS
SPREADING ACROSS THE NORTHEAST THROUGH MONDAY ***
CURRENT WV SATELLITE IMAGERY DENOTES OUR NORTHERN STREAM S/W
MIGRATING THROUGH THE WESTERN DAKOTAS WITH A SOUTHEASTERN
TRAJECTORY INTO THE MIDWEST. SOUTHERN STREAM WAVE CURRENTLY
ENTERING THE MISSOURI VALLEY WILL RENDEZVOUS WITH THE NORTHERN
STREAM WAVE LATER THIS EVENING, BEGINNING A PHASING PATTERN THAT
WILL INITIATE AN INTENSE SYNOPTIC EVOLUTION ALONG THE ATLANTIC
COAST. SURFACE CYCLOGENESIS WILL ENSUE OVERNIGHT JUST OFF THE
NORTH CAROLINA COAST WITHIN A STRONG DIFFLUENT AXIS DOWNSTREAM OF
THE MEAN TROUGH POSITIONED OVER THE OHIO VALLEY, AND WITHIN THE LER
OF A POWERFUL UPPER JET MAX ROUNDING THE BASE OF THE TROUGH. UPPER
LEVEL PROGRESSION ACROSS THE OHIO VALLEY WILL LEAD TO THE
MATURATION OF THE 850-500MB HEIGHT PATTERN ALLOWING FOR EACH LEVEL
TO CLOSE-OFF AS THEY BEGIN TO CUT SOUTHEAST THROUGH THE SOUTHERN
MID-ATLANTIC. THIS WILL BEGIN AN ACCELERATED INTENSIFICATION
PROCESS OF OUR MAIN SURFACE LOW LEADING TO RAPID PRESSURE FALLS AND
EVENTUAL "BOMBING" OF THE CYCLONE.
PRECIPITATION WILL BEGIN EARLY SUNDAY MORNING ACROSS VA AND SLIDE
TO THE NORTHEAST AS A LEAD WAVE KICKS OFF THE STORMS LIFE CYCLE.
MARGINAL THERMAL PROFILES LEADING INTO THE SYSTEM THANKS TO A
MEAGER ANTECEDENT AIRMASS WILL LEAD TO MORE RAIN SOUTH OF THE FALL
LINE ACROSS THE MID ATLANTIC PIEDMONT WITH MORE SNOWFALL FURTHER
NORTH WHERE WETBULB TEMPS ARE FORECAST TO BE NEAR FREEZING. AS THE
TROUGH TO THE WEST BEGINS SWINGING EASTWARD WITH A MORE NEUTRAL TO
BORDERING NEGATIVE TILT, EXPECT RELEVANT HEIGHT FALLS TO HELP
CHANGE PRECIP HYDROMETEOR TYPES FROM A LIQUID/SOLID MIXTURE TO
MORE SOLID, MEANING A FULL CHANGEOVER TO SNOWFALL FOR EVERYONE
OUTSIDE THE LOWER DELMARVA AREA THAT WILL TAKE A BIT LONGER GIVEN
ITS PROXY TO THE MEAN UPPER TROUGH. BY SUNSET, THE MATURING
850-500MB PROGRESSION WILL HAVE TAKEN SHAPE OVER VA LEADING TO AN
EVENTUAL "CAPTURING" OF THE SURFACE REFLECTION AS IT MIGRATES
TOWARDS THE LATITUDE OF THE LOWER DELMARVA, MOST LIKELY OFF THE
COAST OF CHINCOTEAGUE, VA WHERE MAJORITY OF ENSEMBLES AND
DETERMINISTIC ARE PINPOINTING DURING THE 12Z NWP SUITE. THIS WILL
ALLOW FOR AN EVENTUAL SLOWING, EVEN PERHAPS STALLING FOR A SHORT
PERIOD OF TIME OFF THE MID-ATLANTIC COAST WHICH WOULD SET THE STAGE
FOR THE PRIMARY INTENSIFICATION PHASE OF THE CYCLONE.
PRECIP FIELD WILL BLOSSOM AND BECOME MUCH MORE PRONOUNCED BY THE
TIME THIS EVOLUTION OCCURS AND THE ATTENDANT HEIGHT FALLS WITH THE
TROUGH WILL FINALLY SEND THE COLD AIR CRASHING LEADING TO A FULL
CHANGEOVER TO SNOWFALL FOR EVERYONE AS DIABATIC PROCESSES OVERCOME
THE SUBTLE WARM LAYER LEFT IN THE LOWER PBL. INTENSE 850-700MB FGEN
WILL BE LOCATED TO THE WEST AND NORTHWEST OF THE CYCLONE
CORRELATING WITH A BETTER DEFINED BANDING STRUCTURE THAT WILL
COMPRISE OF THE MAIN AXIS OF DEFORMATION. SNOWFALL RATES OF 1+"/HR
WILL BE ALL BUT CERTAIN IN THIS AXIS WITH RATES EXCEEDING 2"/HR
LIKELY ANYWHERE FROM THE LOWER DELMARVA UP THROUGH NJ/LI AND
EVENTUALLY INTO SOUTHEASTERN NEW ENGLAND. FURTHER WEST, A NARROW
AXIS OF HEAVIER PRECIP WILL OCCUR WITHIN THE DEVELOPMENT OF A
NORLUN TROUGH GENERATED BY THE UPPER EVOLUTION FIXED OVER THE MID
ATLANTIC. CURRENT GUIDANCE HAS BEEN STEADY WITH INDICATING THIS
FEATURE LOCATED SOMEWHERE OVER WEST-CENTRAL PA DOWN THROUGH THE
VALLEY EAST OF THE ALLEGHENY FRONT AND INTO THE NORTHERN BLUE
RIDGE OF VA. SOME GUIDANCE HAS BEEN VERY BULLISH WITH THIS NARROW
AXIS LEADING TO ELEVATED QPF DISTRIBUTION THAT WOULD COINCIDE WITH
RELATIVELY HIGHER SLR'S BORDERING BETWEEN 13-15:1 WHICH WOULD LEAD
TO A SECONDARY MAXIMA AWAY FROM THE PRIMARY CCB ASSOCIATED WITH THE
BOMBING SURFACE LOW.
STORM WILL MIGRATE SLOWLY TO THE NORTH-NORTHEAST, THEN NORTHEAST
ONCE APPROACHING JUST SOUTH OF THE LATITUDE OF LI. SURFACE
PRESSURES WILL DROP <980MB ON THIS TRAJECTORY WITH MULTIPLE
SOLUTIONS NOW INDICATING AT LEAST THE LOW-970S TO PERHAPS EVEN
SNEAKING INTO THE 960S IN THE STRONGEST OUTPUTS. WPC PWPF INDICATES
A BROAD AREA OF 70+% PROBABILITIES FOR >4" OF SNOWFALL FROM THE
POTOMAC TO POINTS NORTHEAST WITH AREAS ALONG THE COAST FROM DE TO
MASS WELL OVER 90% FOR THE 4" THRESHOLD. PROBABILITIES OF >8"
(70-100%) EXIST IN THE SAME CORRIDOR WITH EVEN 30-70% EXISTING AS
FAR SOUTHEAST AS THE DC METRO. THE HIGHER END TOTALS >12" (60-90%)
AND >18" (40-70%) ALSO EXIST ACROSS THE LOWER DELMARVA UP THROUGH
NJ/LI/SOUTHEAST MASS, WITH 30-60% PROBS FOR >12" EVEN SITUATED AS
FAR NORTHWEST AS THE PHILADELPHIA METRO AND ALL OF SOUTHEAST PA, A
TESTAMENT TO THE BROAD SCOPE OF SIGNIFICANT SNOWFALL EXPECTED WITH
THIS SYSTEM. HIGH WIND GUSTS >39KTS FOR THE COASTAL AREAS WILL
LEAD TO HEIGHTENED CONCERNS FOR BLIZZARD CONDITIONS WITH NEAR
BLIZZARD CONDITIONS PLAUSIBLE EVEN INTO AREAS AWAY FROM THE
IMMEDIATE COAST.
THIS WILL BE A POWERFUL NOR'EASTER BY DEFINITION THAT WILL HAVE
SIGNIFICANT IMPACTS TO MUCH OF THE MEGALOPOLIS IN SOME DEGREE.
PHILADELPHIA TO BOSTON HAS THE HIGHER POTENTIAL FOR GREATER THAN A
FOOT FOR THE MAIN URBAN ZONES, BUT IMPACTS DOWN INTO THE DC/BALT
METRO ARE CERTAINLY EXPECTED.
..CASCADES AND FAR NORTHERN ROCKIES
DAYS 1-3...
DEEP LOW SHIFTS SOUTH WELL OFF THE BC COAST TODAY BEFORE STALLING
WELL OFF THE WA COAST TONIGHT THROUGH MONDAY. THE FIRST ROUND OF
COASTAL TO CASCADES PRECIP EXITS EARLY TONIGHT WITH DECENT PRECIP
RATES INCREASING TO 3000-4000FT FEET. DAY 1 SNOW PROBS FOR >6" ARE
50-80% MAINLY IN THE WA CASCADES AND THE TRINITY ALPS OF CA.
THERE IS A BIT OF A LULL IN ONSHORE FLOW TONIGHT BEFORE THE NEXT
WAVE ARRIVES ALONG THE CASCADES SUNDAY. SNOW LEVELS RISE TO
4000-5000FT SUNDAY WITH DAY 2 SNOW PROBS FOR >6" AGAIN 50-80% IN
THE WA CASCADES AND THE TRINITY ALPS/MT SHASTA.
THE THIRD WAVE OF PRECIP LINGERS OVER WA SUNDAY NIGHT BEFORE
SHIFTING SOUTH DOWN THE PACNW COAST AND INLAND OVER THE NORTHWEST MT
RANGES MONDAY BEFORE SINKING SOUTHWARD INTO THE ID SAWTOOTHS AND
GREATER YELLOWSTONE REGION OF WY ON TUESDAY. SNOW LEVELS RISE TO
4000-6000FT IN WA/OR AND MT WHILE THEY RISE TO 8000FT IN NORTHERN
CA. DAY 3 SNOW PROBS FOR >6" ARE 50-90% IN THE WA CASCADES, OVER THE
FAR NW MT RANGES, SAWTOOTHS OF ID AND ABSAROKA/TETONS OF WY.
..GREAT LAKES
DAYS 1-2...
AN INVERTED TROUGH LINGERS OVER NORTHERN MICHIGAN THROUGH TONIGHT.
PERSISTENT LOW-LEVEL CONVERGENCE ALONG THIS INVERTED TROUGH
COMBINED WITH STEEPENED LAPSE RATES ALOFT BENEATH A BROAD MID-LEVEL
TROUGH WILL PROMOTE CONTINUED FAVORABLE ASCENT FOR A NARROW
CORRIDOR OF HEAVY SNOWFALL WITH MAX SNOWFALL RATES ABOVE 1"/HR.
A NARROW AXIS WILL CONTINUE TO BE FOCUSED ACROSS THE U.P. WITH DAY 1
WPC PROBABILITIES FOR >6" 30-50% ACROSS THE KEWEENAW PENINSULA AND
THE HURON MOUNTAINS, AND THE CENTRAL U.P. SHORE.
THIS TROUGH WEAKENS SUNDAY, BUT A MID-LEVEL TROUGH DIGS OVER THE
GREAT LAKES, WITH NNWLY FLOW AND CAA INCREASING OVER LAKES SUPERIOR
AND MICHIGAN. DAY 2 SNOW PROBS FOR >4" ARE AROUND 40% FOR THE
PORCUPINE AND HURON MTNS IN THE U.P. AS WELL AS FAR SOUTHWEST MI
INTO NORTHERN IN.
..UPPER GREAT LAKES
DAY 3...
BY TUESDAY A SHORTWAVE DIVING SOUTHEAST FROM SOUTH-CENTRAL CANADA
INTO THE UPPER MIDWEST/GREAT LAKES WILL BE ASSOCIATED WITH A WEAK
AREA OF SURFACE LOW PRESSURE. THIS WILL HELP PRODUCE AN AREA OF WAA
SNOW INTO NORTHEAST MN, NORTHERN WI, AND THE MI U.P.. OVERALL,
SNOWFALL IS EXPECTED TO BE MOSTLY LIGHT, BUT WPC PROBABILITIES FOR
AT LEAST 4" ARE GENERALLY 30-70% (HIGHEST IN THE MN ARROWHEAD AND
CENTRAL MI U.P..
KLEEBAUER/SNELL
...WINTER STORM KEY MESSAGES ARE IN EFFECT. PLEASE SEE CURRENT
KEY MESSAGES BELOW...
HTTPS://WWW.WPC.NCEP.NOAA.GOV/KEY_MESSAGES/LATESTKEYMESSAGE_1.PNG
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