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. $$ --------------------------------------------------------------------------------

119

---

In this thread:

< Return to message board

---

Post A Reply

Subject: Message: Add Smiley: Add Link: Link URL: Link Text (Optional): Add   Add Image: Image URL: Add