045
FXUS02 KWBC 021815
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
214 PM EDT SAT AUG 02 2008
VALID 12Z TUE AUG 05 2008 - 12Z SAT AUG 09 2008
MODEST MODEL AND ENSEMBLE SOLUTION SPREAD OVERALL OVER THE NEXT
WEEK OVER THE NATION BOLSTERS FORECAST CONFIDENCE WITH THE VAST
BULK OF SEEMINGLY METEOROLOGICALLY REASONABLE GUIDANCE OFFERING A
QUITE SIMILAR MID-LARGER SCALE NOAM FLOW PATTERN.
A SOLUTION CLOSEST TO THE 00 UTC ECMWF OVERALL SEEMS TO AFFORD
REASONABLE GUIDANCE ACROSS MUCH OF THE COUNTRY INTO MIDWEEK WITHIN
THE SMALLER THAN NORMAL FULL ENVELOPE OF SOLUTIONS. LATER...IT
SEEMS PRUDENT TO GRADUALLY TRANSITION TOWARD INCLUSION OF
INCREASING AMOUNTS OF SMOOTHING ENSEMBLE MEAN GUIDANCE OVER TIME.
ACCORDINGLY...UPWARDS TO 50% OF ECMWF ENSEMBLE MEAN GUIDANCE WAS
USED IN THE HPC BLEND WITH THE 00 UTC ECMWF BY DAY 7. THE GFS AND
CANADIAN ENSEMBLE MEANS WERE VERY MUCH IN LINE WITH THE BLENDED
SOLUTION AS WELL. THIS MAINTAINS CLOSE HPC CONTINUITY.
..EAST-CENTRAL US
MOST MODELS ARE IN CLOSE AGREEMENT AND FAVOR SIGNIFICANT
AMPLIFICATION OVER ERN NOAM LEADING TO DEVELOPMENT OF A DECIDEDLY
UNSUMMERLIKE VORTEX IN THIS PATTERN DUG DOWN FROM CANADA INTO THE
ERN US DURING THE SECOND HALF OF THE MEDIUM RANGE PERIOD. MOST
MODELS AND ENSEMBLES AGREE THAT LOW 500 HEIGHTS WITH THE VORTEX
COULD EXCEED 3 STANDARD DEVIATIONS BELOW NORMAL CENTERED IN WRN PA
BY DAY 7...SO WILL DOWNPLAY THE FLATER 06 UTC GFS FOR NOW
CONSIDERING THE STRENGTH OF UPSTREAM RIDGING. THIS COOLING SYSTEM
SHOULD ALSO FAVOR INSTABILITY SHOWERS UNDERNEATH AND MEANWHILE
ALLOW AMPLE CONTINUED SUPPORT FOR CONVECTION TO FOCUS NEAR A LEAD
AND WAVY FRONTAL SYSTEM PUSHING THRU THE ERN STATES AND TRAILING
BACK THRU THE S-CENTRAL US TIER.
..EASTERN PACIFIC THRU THE WEST-CENTRAL US
SHORT TERM LOW POTENTIAL INLAND FROM THE NRN GULF OF MEXICO AS PER
TPC MONITORING MAY ACT TO FOCUS DEEP LAYERED TROPICAL MOISTURE
ACROSS TX AND THAT MAY EVENTUALLY FEED INTO THE ESTABLISHED
MONSOONAL FLOW ACROSS NRN/NW MEX AND INTO THE WRN US UNDER THEN
AROUND THE WRN PERIPHERY OF THE CENTRAL NOAM RIDGE. HOWEVER...THE
SMALLER SCALE DETAILS SEEM TO HAVE LOW PREDICTABILITY AND
SIGNIFICANT RUN TO RUN CONTINUITY ISSUES SO INCLUDED INCREASING
AMOUNTS OF ENSEMBLE MEAN GUIDANCE INTO THE PREFERRED HPC GUIDANCE
MIX OVER TIME TO ADDRESS THIS.
FARTHER WEST...THE LAST FEW GFS RUNS REMAIN OUTLIERS WITH RESPECT
TO MOST OTHER GUIDANCE IN DIGGING SUCH AN IMPRESSIVELY AMPLIFIED
TROUGH SOUTHWARD OVER THE E PAC NEAR 135W THRU THE END OF THE WEEK
INTO NEXT WEEKEND. PREFER TO RELY ON FARTHER NORTH/FLATTER IDEAS
MORE IN LINE WITH THE 00 UTC ECMWF THAT HAS TREMENDOUS GFS/ECMWF
ENSEMBLE SUPPORT. HOWEVER....HPC PROGS WERE MORE RELUCTANT TO
BRING MUCH OF A FRONTAL PUSH INTO THE NW US INTO NEXT WEEKEND
CONSIDERING POTENTIAL TO HOLD MORE FORCING ENERGY OFFSHORE...AT
LEAST RESPECTING THE GFS.
CISCO/SCHICHTEL
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