Re: HPC Discussion - ...MAJOR WINTER STORM ANTICIPATED
Posted by Fred on 2/3/2010, 8:45 am
PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
759 AM EST WED FEB 03 2010

VALID 12Z SUN FEB 07 2010 - 12Z WED FEB 10 2010

...MAJOR WINTER STORM OVER A PORTION OF THE MID ATLANTIC REGION
LATE FRI/SAT...

THERE ARE ENOUGH MODEL DIFFERENCES HANDLING VORTICES IN A MEAN
TROF OVER CENTRAL AND ERN CANADA TO USE A SIMPLIFIED BETTER AGREED
UPON ENS MEANS FOR PROGS AND H500S. DAYS 6 AND 7 HAVE CLOSER
SIMILARITY BETWEEN THE OP GFS AND THE 00Z ECMWF ENS MEAN AND A
LAGGED AVERAGE FORECAST OF BOTH GFS AND ECMWF. HPC PROG BLENDS
INCORPORATE 00Z ECMWF AND 00Z GFS ENS MEANS THRU DAY 5 MON AND A
BLEND OF 00Z OP GFS AND THE 00Z ECMWF ENS MEAN DAYS 6 AND 7
TUES/WED.

MID ATLC OFFSHORE STORM DAY 3 SAT HAS A GOOD CONSENSUS AMONG
MODELS FOR HEAVY RAINFALL OVER THE SOUTHEASTERN SEABOARD. A VERY
HEAVY EVEN CRIPPLING SNOW IS LOOKING LIKELY OVER A RELATIVELY
SMALL AREA FROM SRN NJ/SOUTHEAST PA/DE/MD/NRN VA/ERN PANHANDLE DAY
3 FRI NIGHT INTO SAT. THIS AREA WILL BE UNDER THE RIGHT REAR
ENTRANCE REGION OF THE NRN STREAM JET WITH A BRIEF COUPLING OF THE
SRN STREAM LEFT FRONT EXIT REGION WITH VERY STRONG VERTICAL
VELOCITIES. OVERALL MODEL QPF CONSENSUS AVERAGE 1-1.5 LIQUID
EQUIVILENT OVER AREAS COLD ENOUGH FOR SNOW INDICATES POTENTIAL
SNOWFALL AMOUNTS IN THE 1-2 FOOT RANGE. GALE FORCE ONSHORE WINDS
CONT ALONG THE DELMARVA/NJ COAST SAT AS A DEEPENING SFC LOW EXITS
THE NC SOUNDS AND MOVES EAST OF THE VA CAPES. THERE ARE
SIMILARITIES TO THE FEB 11-12 1983 STORM WITH A MORE SUPRESSED NRN
EDGE TO THE PCPN AND AS FAR SOUTH WITH COLD AIR. VERY COLD AIR
PUSHING SWD THRU THE PLAINS WILL ALSO COVER ERN CONUS AFTER THE
LOW MOVES EWD WITH WELL BELOW NORMAL TEMPS THRU THE NEXT WEEK. SEE
LOCAL NWS ADVISORIES AND WARNINGS AND HPC WINTER WEATHER GUIDANCE.

MID LEVEL SRN STREAM SHORTWAVE MAY INDUCE ANOTHER GULF COAST LOW
MID WEEK WITH ANOTHER WINTER WEATHER THREAT ALONG ITS NORTH SIDE
THRU THE SRN PLAINS/TN VALLEY AND MID ATLC REGION MID WEEK.

MDT/HVY PCPN ACROSS CA SAT AND SUN WITH ONLY MUCH WEAKER SYSTEMS
STAYING OFFSHORE REMAINDER OF THE PERIOD.
ROSENSTEIN
 



Also have heard of a possible big storm next tue-wed
61
In this thread:
Possible Significant Storm Friday - IN to VA to FL - JAC, 2/2/2010, 3:59 pm
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