506
FXUS02 KWBC 041754
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
154 PM EDT SAT JUL 04 2009
VALID 12Z TUE JUL 07 2009 - 12Z SAT JUL 11 2009
MODELS AND ENSEMBLES CONTINUE TO SHOW A REASONABLY SIMILAR LARGER
SCALE MEDIUM RANGE FLOW PATTERN ACROSS MUCH OF NOAM. THIS
PERSISTENT PATTERN HAS PRETTY MUCH BEEN PREVALENT FOR THE LATE
SPRING/EARLY SUMMER AS COMPRISED ALOFT OF COOLING MEAN TROUGHS
CENTERED ALONG/JUST OFF THE PACIFIC NORTHWEST COAST AND DOWNSTREAM
OVER ERN NOAM...SANDWICHING HOT MID-US RIDGING.
WHILE FORECAST CONFIDENCE IN THE LARGER SCALE PATTERN IS
RELATIVELY GOOD...RUN TO RUN CONSISTENCY/SENSITIVITY WITH EMBEDDED
SMALLER SCALE SYSTEMS/INTERACTIONS/SENSIBLE WEATHER FOCUS AND
INCREASED MODEL AND ENSEMBLE MEMBER SOLUTION SPREAD POINTS TO MUCH
LOWER PREDICTABILITY AND FORECAST CONFIDENCE. ENSEMBLE MEANS
CERTAINLY PROVIDE BETTER RUN TO RUN CONSISTENCY...BUT AT THE PRICE
OF INCREASINGLY BLAND SYSTEM DEPICTIONS OVER TIME DURING THE WARM
SEASON IN PARTICULAR. THIS REMAINS TRUE EVEN IN THIS TYPE OF
PATTERN THAT SEEMS TO HAVE SOME DECENT EMBEDDED SYSTEMS WITH
DEFINED SURFACE FEATURES AND GRADIENTS DAYS 4-7.
ACCORDINGLY...PREFER DAYS 4-7 TO NOT PREFER ANY SOLUTION PER SE
BUT INSTEAD DAMPEN SMALLER SCALE DETAILS OF THE 00 UTC ECMWF BY
BLENDING 30% 06 UTC GFS IN LUE OF ENSEMBLE MEAN USAGE.
HOWEVER...FINAL HPC PROGS OFFER SOME MANUAL ADJUSTMENTS FROM OUR
PRELIM GUIDANCE TO MORE FAVOR A DEEPER NERN US TROF SOLUTION TUE
INTO WED AS PER SHORT RANGE DESK PREFERRENCE AND FAVORABLE
UPSTREAM FLOW...TRENDING TOWARD THE 12 UTC GFS. HOWEVER...WE SEE
NO COMPELLING REASON TO CHANGE HPC CONTINUITY FOR OUR FINAL PROGS
FOR LATER NEXT WEEK INTO NEXT WEEKEND AS THE 12 UTC GFS HAS
TRENDED TOWARD OUR PRELIM GUIDANCE SOLUTIONS.
THE 00 UTC ECMWF OFFERS DECENT LARGER SCALE CONTINUITY AND FITS
THE PERSISTENT PATTERN A LITTLE BETTER COMPARED TO RECENT GFS RUNS
THAT HAS TENDED TO FILL THE NORTHEASTERN TROUGH TOO MUCH BY THE
END OF THE PERIOD...A BIAS SEEN IN THIS MODEL SINCE THE SPRING.
IN THIS PATTERN THE ECMWF AND ECMWF ENSEMBLES FOCUS MORE TROFFING
ALOFT OFFSHORE THE WRN US THU-SAT WHICH LEADS TO MORE DOWNSTREAM
TROFFING THAN THE GFS AND GFS/NAEFS ENSEMBLE MEANS THROUGH THE
GREAT LAKES/MIDWEST THEN ERN US. PREFER THOUGH TO STILL BLEND IN
30% 06 UTC GFS DUE TO UNCERTAINTY AND CONSIDERING ECMWF ENERGY
TRANSFER CHANNELED BETWEEN NRN CANADIAN CLOSED VORTEX ENERGY AND
CENTRAL US RIDGING MAY WELL BE SOMEWHAT OVERDONE/DEFINED.
CISCO/SCHICHTEL
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