HPC Discussion East Coast Event=Heavier precip offshore?

[cycloneye]

PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
347 AM EST TUE JAN 18 2005

VALID 12Z SAT JAN 22 2005 - 12Z TUE JAN 25 2005

PRELIMINARY MEDIUM RANGE DISCUSSION...

THE MEDR PRES PROGS CLOSELY RESEMBLE THE 00Z GFS. SPEEDING UP THE
SYS PULLING OFF THE MID ATL COAST ON DAY 4/SAT IS THE MOST
SIGNIFICANT CHANGE FROM THE PREVIOUS HPC PROGS.

THE 00Z CAN GLOB...NOGAPS...GFS...AND NCEP ENS MEAN HAVE ALL
TRENDED MORE PROGRESSIVE WITH THE SYS. THE UKMET CONTINUES TO BE
THE SLOWEST SOLN WHILE THE 00Z ECMWF IS THE LARGEST OUTLIER AND A
SIGNIFICANT CHANGE FROM ITS CONTINUITY...CUTTING OFF AN APPROX 522
DM LOW OVER THE NRN MID ATL BY 24/00Z. NOT ONE 00Z NCEP ENS MEMB
HAS A SOLN LIKE THE ECMWF...AND ONLY THE 18Z DGEX...WHICH IS STILL
WEAKER AND MORE PROGRESSIVE... RESEMBLES THE 00Z ECMWF SOLN. BOTH
THE DGEX AND 00Z ECWMF...ALONG WITH THE UKMET...SEEM TO AMPLIFY
THE H5 TROF GREATER THAN THE OTHER GUIDANCE BECAUSE THEY
INCORPORATE MORE OF THE ENERGY FROM THE H5 LOW WHICH MIGRATES
INLAND FROM OFF THE BAJA INTO THE TROF. CONSIDERING THE EXCELLENT
RUN TO RUN CONSISTENCY OF THE 00Z AND 12Z RUNS OF THE GFS...DO NOT
FEEL CONFIDENT STRAYING FROM ITS FORECAST. THE SYS STILL HAS THE
POTENTIAL TO BE A SIGNIFICANT SNOW MAKER FROM THE NRN PLAINS THRU
THE MID ATL/SRN NEW ENG COAST...BUT WITH THE PREFERRED GFS
TRENDING MORE PROGRESSIVE...THE HEAVIER PRECIP IS MORE LIKELY TO
BE OFFSHORE. THIS SYS BEARS WATCHING OVER THE NEXT FEW DAYS.

THE FAVORED...MORE PROGRESSIVE H5 TROF MOVING INTO THE WRN ATL ON
DAY 5/SUN AS PER THE 00Z GFS SHUD ALLOW FOR MORE RIDGING TO BUILD
BETWEEN IT AND THE POLAR VORTEX OVER N CNTRL CAN WHICH IS FORECAST
BY ALL OF THE MODELS TO INCH SEWD THRU THE END OF THE PD. THIS
SHUD ALLOW FOR SLIGHTLY WARMER TEMPS IN THE NERN QRTR OF THE CONUS
ON DAYS 6/MON AND 7/TUES THAN THE PREVIOUS HPC FORECAST.

THE MORE AMPLIFIED PATTERN OF THE 00Z ECMWF CAUSES IT TO BLOCK THE
SRN STREAM SHRTWV SYS XPCT TO MOVE INTO THE NW ON DAY
6/MON...CAUSING IT TO STALL IN THE PAC. ALL OF THE OTHER MODEL
APPEAR TO BE MORE PROGRESSIVE THAN THE 00Z ECMWF BY THE END OF
THEIR RUNS...WITH THE 00Z NOGAPS...17/12Z ECMWF...AND THE 18Z DGEX
IN GOOD AGREEMENT WITH THE SLOW TIMING OF THE GFS. PREFER THE 00Z
GFS.

CLARK


It says that the most heavier precipitation will be offshore according to the latest GFS run that they mention and they are following more strongly.But still there is time to see changes in the next runs so those who want to see a good deal of snow hang in there.