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FXUS02 KWBC 011844
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
143 PM EST SUN NOV 01 2009
VALID 12Z WED NOV 04 2009 - 12Z SUN NOV 08 2009
TELECONNECTIONS WITH A MOBILE/FLAT POSITIVE ANOMALY NEAR 43N 130W
FAVORS TROUGHING ALOFT ANYWHERE BETWEEN THE MIDWEST AND NORTHEAST.
WHERE EXACTLY IT SETS UP IS QUITE SENSITIVE TO THE ORIENTATION OF
THE ANOMALY CENTER...WHICH IS EXPECTED TO BE EAST-WEST ORIENTED.
THIS SENSITIVITY HAS BEEN SEEN IN THE GLOBAL GUIDANCE OVER THEIR
PAST FEW DAYS OF RUNS...WHICH HAVE DISPLAYED TROUGH/CLOSED CYCLONE
SOLUTIONS IN A VARIETY OF LOCATIONS BETWEEN THE FRONT RANGE OF THE
ROCKIES AND THE CANADA MARITIMES. FLOW ORIENTATION IN THE BULK OF
GUIDANCE OVER THE ERN PACIFIC SEEMS THOUGH TO BEST FAVOR A GENERAL
WEST-CENTRAL US RIDGE AND ERN US TROUGH CONFIGURATION ALOFT
HEADING INTO NEXT WEEKEND. THE AMPLIFIED OUTLIER IS THE
CANADIAN...WHICH SHIFTED ITS TROUGHING WELL TO THE EAST OVER ITS
PAST DAY OF RUNS. THE ECMWF HAS NOT SHOWN MUCH STABILITY FROM DAY
TO DAY EITHER. CONSIDERING POOR RUN TO RUN CONSISTENCY AND HIGH
SOLUTION SPREAD DAYS 4-7 WITH EMBEDDED SYSTEMS...STILL PREFER AN
MAINLY ENSEMBLE MEAN APPROACH. ACCORDINGLY...HPC MEDIUM RANGE
GUIDANCE WAS PRIMARILY DERIVED FROM THE 00 UTC GFS ENSEMBLE MEAN.
HOWEVER...I DID BLEND IN ABOUT 30% 12 UTC GFS FOR THE FINAL PROGS
TO TAKE ADVANTAGE OF NEWER/HIGHER RESOLUTION GUIDANCE EARLY PERIOD
INPUT CONSIDERING THERE WAS DECENT TREND SUPPORT FROM OTHER 12 UTC
GUIDANCE. THIS SOLUTION REMAINS GENERALLY WELL SUPPORTED BY ECMWF
ENSEMBLES FOR MUCH OF THE UPCOMING WEEK AND FINAL PROGS CHANGES
ARE MINIMAL...SO THEY STILL MAINTAIN CLOSE HPC CONTINUITY AMID
HIGH UNCERTAINTY.
ROTH/SCHICHTEL
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