Major Winter Event: Mid Atlantic & Ohio Valley. Blizzard Warnings Up DE & NJ Coast
Posted by JAC on 2/4/2010, 2:29 pm









PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
328 AM EST THU FEB 04 2010

MID-ATLANTIC/APPALACHIANS AND OH VLY/INTERIOR SOUTHEAST...
EVERYTHING IS STILL ON TRACK FOR A MAJOR WINTER EVENT FROM THE
MID-ATL BACK THROUGH LWR OH VLY...PLUS A SEVERE ICING EVENT IN THE
SRN APPALACHIANS.  TREMENDOUS MSTR SURGE/WAA WILL INITIALLY AFFECT
THE SRN APPALACHIANS THURS NIGHT WHERE THE RAINFALL WILL ENCOUNTER
FZ SURFACES RESULTING IN NEARLY AN INCH OF ICE ACCUMULATION IN WRN
NC/SC TO SW VA/SRN WV. THINGS GET COMPLICATED FARTHER NORTH WHERE
ONLY A SHALLOW AIR MASS WILL REMAIN INTACT UNDER 50 TO 60 KT OF
850 MB SRLY WAA.  MODELS ARE INSISTENT THAT THE COLUMN WILL REMAIN
SUPPORTIVE OF SNOW FROM ROUGHLY THE NRN 1/2 TO 2/3 OF VA NWD
RESULTING IN PROLIFIC ACCUMULATIONS OVERNIGHT.  THEN ON SAT... THE
DEVELOPING AREA OF LOW PRESSURE ALONG THE NC/MID-ATL COAST WILL
DEEPEN RAPIDLY AS NRN STREAM DYNAMICS PHASE WITH THE SRN STREAM
SYSTEM AND ALLOW THE UPPER TROUGH AXIS TO GO NEG TILT. THIS WILL
ALLOW AN INCREDIBLE AMOUNT OF GULF/ATLANTIC MOISTURE TO INVADE THE
MID-ATL REGION AND FLOURISH UNDER THE PROGGED COUPLING OF UPPER
JET STREAKS FOR THE DEVELOPMENT OF A SIGNIFICANT COMMA
HEAD/DEFORMATION ZONE FROM COASTAL NJ/DE/MD WEST THROUGH MD/VA/SRN
PA INTO WV AND SERN... RESULTING IN ANOTHER ROUND OF PROLIFIC
ACCUMULATIONS IN THE COLD SECTOR.  INTERESTINGLY... THE TIMING OF
THIS STORM PRECLUDED A LARGER HIGH RISK OF 12 INCHES ON THIS
SHIFT... BECAUSE THE STORM AMTS WERE BASICALLY SPLIT IN TWO AT
12Z.    

00Z MODELS LARGELY RETAINED THE SAME TENDENCIES AS IN THEIR
EARLIER CYCLES.  NAM IS STILL ON THE SLOW/AMPLIFIED EDGE ALTHOUGH
THE 00Z ECMWF TRENDED THIS DIRECTION AS WELL...WHILE THE GFS
REMAINS FAST.  YET WITH ALL THESE DIFFERENCES... THE QPF AXIS AND
THERMAL PROFILES ARE ALL FAIRLY SIMILAR AMONG THE 00Z GUIDANCE...
WHICH LEAVES TIMING AS THE NOTABLE VARIABLE.  ONE EXCEPTION IS
CNTRL KY WHERE THE NAM IS THE ONLY PIECE OF GUIDANCE TO GIVE SIG
SNOWFALL... SO IT WAS DISCOUNTED.  21Z SREF/12Z ECMWF WERE THE
LATITUDINAL AND TIMING COMPROMISES... SO THEY WERE USED PRIMARILY
FOR ALL ASPECTS OF THIS STORM.  THE OVERARCHING TREND HAS BEEN
WETTER... AND LIQUID-EQUIV PRECIP IS PROGGED TO BE OVER 1.5 INCHES
FOR D.C. AREA... OVER 2 INCHES SWD INTO VA.  SLR/S WILL MEANDER
NEAR 10-1 OR LESS FRI/FRI NIGHT... THEN INCREASE AS THE LOW PASSES
ON SATURDAY MORNING.  CLOSEST ANALOG ACCORDING TO ST LOUIS
UNIV/CIPS PAGE IS 02/12/1983 WHICH GAVE WRN SUBURBS OF D.C. 18+
INCHES... AND 15-18 IS WHAT THE MODEL CONSENSUS...SREF/ECMWF... IS
SUPPORTING FOR D.C. WITH GREATER AMTS WEST.            
 

SOWKO








BLIZZARD WARNING

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
143 PM EST THU FEB 4 2010

DEZ002>004-NJZ020>027-051100-
/O.UPG.KPHI.WS.A.0002.100205T2100Z-100207T0000Z/
/O.NEW.KPHI.BZ.W.0001.100205T2100Z-100207T0000Z/
KENT-INLAND SUSSEX-DELAWARE BEACHES-OCEAN-CUMBERLAND-ATLANTIC-
CAPE MAY-ATLANTIC COASTAL CAPE MAY-COASTAL ATLANTIC-COASTAL OCEAN-
SOUTHEASTERN BURLINGTON-
INCLUDING THE CITIES OF...DOVER...GEORGETOWN...REHOBOTH BEACH...
JACKSON...MILLVILLE...HAMMONTON...CAPE MAY COURT HOUSE...
OCEAN CITY...ATLANTIC CITY...LONG BEACH ISLAND...
WHARTON STATE FOREST
143 PM EST THU FEB 4 2010

...BLIZZARD WARNING IN EFFECT FROM 4 PM FRIDAY TO 7 PM EST
SATURDAY...

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY HAS ISSUED A BLIZZARD
WARNING...WHICH IS IN EFFECT FROM 4 PM FRIDAY TO 7 PM EST
SATURDAY. THE WINTER STORM WATCH IS NO LONGER IN EFFECT.

A STORM SYSTEM DEVELOPING OVER THE GULF OF MEXICO TODAY WILL PASS
OFF THE CAROLINA COAST FRIDAY NIGHT AND THEN CONTINUE TO THE
NORTHEAST ON SATURDAY. SNOW FROM THIS SYSTEM WILL OVERSPREAD THE
REGION FROM SOUTH TO NORTH FRIDAY AFTERNOON...THEN CONTINUE THROUGH MUCH
OF SATURDAY. SNOWFALL TOTALS OF 12 TO 18 INCHES ARE EXPECTED NEAR THE
DELAWARE AND CENTRAL NEW JERSEY COAST WITH UP TO 24 INCHES
POSSIBLE OVER SOUTHERN NEW JERSEY AND THE CENTRAL DELMARVA.
STRENGTHENING WINDS FRIDAY NIGHT AND SATURDAY WILL CREATE BLOWING
AND DRIFTING SNOW WHICH WILL REDUCE VISIBILITIES TO UNDER ONE-
QUARTER MILE AT TIMES.

A BLIZZARD WARNING MEANS SEVERE WINTER WEATHER CONDITIONS ARE
EXPECTED. FALLING AND BLOWING SNOW WITH STRONG WINDS AND POOR
VISIBILITIES ARE LIKELY. THIS WILL LEAD TO WHITEOUT
CONDITIONS...MAKING TRAVEL EXTREMELY DANGEROUS. CONTINUE TO
MONITOR THE LATEST FORECASTS FROM YOUR NATIONAL WEATHER SERVICE.

$$


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Major Winter Event: Mid Atlantic & Ohio Valley. Blizzard Warnings Up DE & NJ Coast - JAC, 2/4/2010, 2:29 pm
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