Prognostic Meteorological Discussion
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000
FXUS02 KWBC 141542
PMDEPD

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1141 AM EDT SUN SEP 14 2014

VALID 12Z WED SEP 17 2014 - 12Z SUN SEP 21 2014

...OVERVIEW AND GUIDANCE EVALUATION/PREFERENCES...

LATEST GUIDANCE CONTINUES TO SHOW A MEAN PATTERN CONSISTING OF A
NERN PAC TROUGH WITH RIDGE/TROUGH CONFIGURATION DOWNSTREAM OVER
NOAM.  THE MOST PROMINENT FOCUS OF THE MEDIUM RANGE FCST IS STILL
THE HANDLING OF ENERGY WITHIN AN INITIAL ERN PAC TROUGH... A
MAJORITY OF WHICH SHOULD PROGRESS INLAND AND REACH THE ERN NOAM
MEAN TROUGH POSN BY LATE IN THE PERIOD... AND ITS INFLUENCE ON
LEADING MSTR/ENERGY FROM ERN PAC HURCN ODILE.


FROM DAY 3 WED INTO DAY 4 THU AN AVG OF THE 06Z GFS/GEFS AND 00Z
ECMWF/ECMWF MEAN SOLNS LOOKS GOOD WITH NO PROMINENT
EXTREMES/OUTLIERS.  THE 00Z GFS WAS FASTER THAN OTHER GUIDANCE
WITH LEADING HGT FALLS PROGRESSING THROUGH THE WEST INTO THE
NRN-CNTRL PLAINS BUT TRENDS CLOSER TO CONSENSUS NEXT WEEKEND.

OTHERWISE... TAKEN AS A WHOLE THE OPERATIONAL MODELS HAVE BEEN
MORE VARIABLE THAN DESIRED WITH IMPORTANT DETAILS FOR THE
PROGRESSIVE TROUGH OF INTEREST.  OVER THE PAST DAY THERE HAS BEEN
SOME CLUSTERING OF SOLNS TOWARD THE IDEA OF PULLING A MODEST
AMOUNT OF ERN PAC TROUGH ENERGY INTO A COMPACT UPR LOW NEAR THE CA
COAST WHILE THE REMAINDER OF THE TROUGH CONTINUES EWD.  THE 06Z
GFS HAS TRENDED SLOWER WITH ITS SRN PART OF THE TROUGH BUT REMAINS
EWD AND MORE OPEN VERSUS THE 00Z ECMWF/UKMET/CMC FRI-SUN.  THE
SIMILAR 06Z GEFS/00Z ECMWF MEANS OFFER A REASONABLE COMPROMISE
WITH SLOWER TIMING BUT A LESS CLOSED DEPICTION.  THROUGH THE REST
OF THE PERIOD THE ENSEMBLE MEANS ARE QUITE SIMILAR FROM THE ERN
PAC ACROSS NOAM.  TELECONNECTIONS RELATIVE TO NEG ANOMALIES OVER
THE NERN PAC AND POSITIVE ANOMALIES NEAR THE NRN ROCKIES BY D+8
GIVE ADDED CONFIDENCE TO THE ENSEMBLE MEAN FCSTS... SO THE 06Z
GEFS/00Z ECMWF MEANS ARE FAVORED FOR DAYS 5-7 FRI-SUN.  BY LATE IN
THE FCST THE 00Z ECMWF BECOMES THE MOST PROMINENT EXTREME WITH THE
AMPLITUDE OF ITS MIDWEST TROUGH ALOFT.  BY DAY 7 SUN IT IS NOT
QUITE AN OUTLIER BUT FEW 00Z ENSEMBLE MEMBERS ARE AS AMPLIFIED AS
THE 00Z ECMWF RUN.

CONSULT LATEST NHC PRODUCTS FOR LATEST INFO REGARDING ERN PAC
HURCN ODILE.  GUIDANCE SHOWS LESS SPREAD FOR ODILE`S TRACK TODAY
BUT UNCERTAINTY WITH THE PRECISE EVOLUTION OF THE UPSTREAM TROUGH
ALOFT TEMPERS CONFIDENCE REGARDING THE PATH AND TIMING/PERSISTENCE
OF ASSOC MSTR/ENERGY OVER THE WRN U.S..


...SENSIBLE WEATHER HIGHLIGHTS...

EVEN WITH SOME OF THE DETAIL UNCERTAINTIES... GUIDANCE HAS BEEN
REASONABLY STABLE IN DEPICTING AN AXIS OF MAXIMUM PRECIPITABLE
WATER ANOMALIES OF 3-5 STDEVS ABOVE NORMAL EXTENDING FROM NRN BAJA
CALIF THROUGH SRN CA AND N/NE INTO THE N-CNTRL ROCKIES WED-THU.
BASED ON LATEST CONSENSUS/TRENDS ALOFT EXPECT MSTR TO LINGER OVER
THE SOUTHWEST FOR A SOMEWHAT LONGER TIME THAN 00Z GFS/GEFS SOLNS.
TO THE N OF THE U.S.-MEXICO BORDER GUIDANCE QPF APPEARS A LITTLE
LESS IMPRESSIVE THAN WAS THE CASE A FEW DAYS AHEAD OF THE PREVIOUS
HVY RNFL EVENT OVER THE SOUTHWEST.  HOWEVER OVER THE
AFOREMENTIONED AREA THE AVBL MSTR MAY STILL SUPPORT LOCALIZED RNFL
MAXIMA IN EXCESS OF A DETERMINISTIC MODEL OR HUMAN FCST.  SOME OF
THIS MSTR MAY THEN SUPPORT HVY RNFL ALONG A FRONT CROSSING THE
PLAINS/MS VLY BUT STEADY MOVEMENT OF THE FRONT MAY BE A MITIGATING
FACTOR.  THE OTHER FOCUS FOR LOCALLY ENHANCED RNFL DURING THE
PERIOD SHOULD BE NEAR A WAVY FRONT DRIFTING OFF THE GULF/SERN
COASTS.

ON WED-THU AN AREA OF VERY WARM TEMPS REACHING AT LEAST 10-15F
ABOVE NORMAL AT SOME LOCATIONS SHOULD EXTEND FROM THE INTERIOR NW
INTO THE NRN PLAINS AHEAD OF THE APPROACHING ERN PAC UPR TROUGH.
AFTER A BRIEF COOLDOWN WITH TROUGH PASSAGE THE NWRN STATES WILL
LIKELY SEE A RETURN TO SIMILAR WARM ANOMALIES BY NEXT SUN AS
RIDGING ALOFT REBUILDS.  ON THE OTHER HAND ERN STATES SHOULD BE ON
THE COOL SIDE ALBEIT WITH THE MAJORITY OF ANOMALIES IN THE SINGLE
DIGITS BELOW NORMAL AND MODERATION TOWARD NEAR NORMAL LVLS FOR MAX
TEMPS AND ABOVE NORMAL FOR MINS TO THE W OF THE APLCHNS BY NEXT
FRI-SUN.

RAUSCH

$$





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