289
FXUS10 KWNH 211843
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
142 PM EST FRI NOV 21 2008
VALID NOV 21/1200 UTC THRU NOV 25/0000 UTC
..SEE NOUS42 KWNO ADMNFD FOR STATUS OF UPPER AIR INGEST
FINAL 12Z MODEL EVALUATION INCLUDING THE ECMWF
MODEL INITIALIZATION ERRORS ARE DESCRIBED UNDER THE RELEVANT
SYSTEM HEADING.
..ERN PAC TROF NEARING THE WEST COAST BY MON
AS THE TROF NEARS THE WEST COAST THERE IS SIGNIFICANT SPREAD AMONG
MODELS AND SREF/GEFS/ECMWF ENSEMBLES REGARDING THE EVOLUTION OF
MID LVL ENERGY THAT PROGRESSES INTO WRN CANADA AND POSSIBLY THE
PAC NW... VERSUS REMAINING ENERGY THAT MAY CUT OFF TO THE W OF CA.
THE CANADIAN GLBL/NOGAPS ARE THE MOST HESITANT TO SEPARATE FLOW
AS THE TROF REACHES THE WEST COAST LEADING TO MORE ENERGY REACHING
CA BY THE END OF THE PERIOD THAN WHAT OTHER MODELS AND 09Z
SREF/12Z GEFS/00Z ECMWF ENSEMBLE MEANS SHOW. THUS PREFER TO LEAN
AWAY FROM THE CMC/NOGAPS SOLNS.
AMONG REMAINING GUIDANCE CLOSER TO THE MIDDLE OF THE SPECTRUM...
WITH THE SYSTEM CLOSING OFF TO THE W OF CA THE NAM AND GFS OFFER
SIMILAR SOLNS ASIDE FROM THE GFS BEING SOMEWHAT DEEPER/NWWD. THE
UKMET IS SIMILAR TO THE GFS BUT SLIGHTLY FARTHER E/NE. THE 09Z
SREF/12Z GEFS MEANS FAVOR A SOLN SLIGHTLY WEAKER/NEWD VERSUS THE
NAM WHILE THE 00Z ECMWF MEAN IS A LITTLE MORE SHEARED. THE 12Z
ECMWF TREND TO A COMPROMISE AMONG THIS CLUSTER... VERSUS ITS MORE
SWWD ELONGATED 00Z SOLN... PROVIDES SOME INCREASE IN CONFIDENCE.
WITH THE SHRTWV TRACKING INTO WRN CANADA... THE NAM MAINTAINS A
RATHER NEUTRAL TILT VERSUS A MUCH MORE POSITIVELY TILTED SHRTWV IN
THE GFS. THE FULL ARRAY OF MODEL/ENSEMBLE GUIDANCE RECOMMENDS A
COMPROMISE BETWEEN THE GFS AND NAM EXTREMES. OVER THE PAST DAY
THE NAM HAS BEEN TRENDING FASTER WITH THE OVERALL TROF. THE GFS
HAS TRENDED FASTER WITH THE NRN SHRTWV REACHING WRN CANADA BUT
SHOWS VERY POOR CONTINUITY OFF CA. THESE TRENDS ALONG WITH THE
ABOVE AVG UNCERTAINTY FAVOR AN INTERMEDIATE SOLN AMONG THE 12Z
MODELS AND ENSEMBLE MEANS. THE 12Z ECMWF PROVIDES THE BEST
INDIVIDUAL SOLN FOR THE EVOLUTION OF ERN PAC ENERGY.
..TROF PROGRESSING INTO THE NWRN CONUS/WRN CANADA SAT
COMPARING THE AXIS OF DRIEST MID LVL RH IN THE NAM ANALYSIS TO WV
IMAGERY SUGGESTS THE MODEL MAY INITIALIZE PORTIONS OF THE SHRTWV
ABOUT 50-75 NM TOO FAR NWWD. OVERALL THE GFS ANALYSIS IS ONLY
SLIGHTLY MORE ACCURATE. AS THE SHRTWV CROSSES THE PAC NW THE NAM
IS A LITTLE MORE AMPLIFIED THAN THE GFS/00Z ECMWF AND LATEST
SREF/GEFS/ECMWF ENSEMBLE MEANS. THE NAM GENERALLY LAGS OTHER
MODEL/ENSEMBLE GUIDANCE WITH THE TRAILING TROF ENERGY THAT CROSSES
THE WEST/PLAINS. DIFFS WITH TROF TIMING DIMINISH E OF THE MS
RIVER BUT THEN THE GFS BECOMES MORE AMPLIFIED THAN THE NAM OR
OTHER 12Z MODELS WITH THE CNTRL PART OF THE TROF. THERE IS SOME
SCATTER AMONG THE 12Z MODELS WITH THE CLOSED LOW TRACKING INTO THE
GRTLKS BY MON. THE 12Z ECMWF TRENDS SW OF THE 12Z MODEL CLUSTER
BY LATE SUN INTO MON BUT SREF/GEFS/ECMWF ENSEMBLES OFFER LITTLE
SUPPORT FOR SUCH A SCENARIO. THE OVERALL RESULT OF DIFFS ALOFT IS
THAT THE NAM IS SLOWER THAN THE GFS WITH MOST OF THE LEADING SFC
FRONT CROSSING THE PLAINS/EAST. CONSENSUS OF 12Z MODELS AND
SREF/GEFS/EC ENSEMBLE GUIDANCE LEANS MORE TOWARD THE GFS FRONTAL
PROGRESSION OVER THE CNTRL CONUS AND THEN A COMPROMISE HALF TO TWO
THIRDS TOWARD THE GFS OVER THE EAST. A COMPROMISE AMONG THE UKMET
AND 00Z ECMWF... WHICH IS NOT QUITE AS EXTREME AS THE NEW 12Z
RUN... PROVIDES THE BEST OVERALL REPRESENTATION OF THE PREFERRED
CONSENSUS FOR THIS SYSTEM THRU THE FCST PERIOD. THE GFS IS ALSO
REASONABLE THRU F60 LATE SUN.
..SHRTWV INITIALLY HEADING INTO THE NRN PLAINS
THE GFS BECOMES SLIGHTLY WEAKER THAN THE NAM WITH THE CORE OF THE
MID LVL SYSTEM OVER THE MID MS VLY/OH VLY AND TRENDS SLIGHTLY
FASTER THAN THE NAM TO THE E OF THE MS RIVER. THE 12Z
ECMWF/UKMET/CANADIAN GLBL ALL FAVOR SLIGHTLY SOMEWHAT GREATER
WEAKENING THAN THE NAM OVER THE MS/OH VALLEYS BUT STILL DIFFER
SLIGHTLY ON TIMING AS THE SHRTWV TRAVELS TOWARD THE SERN COAST.
GFS/NAM TRENDS OVER THE PAST COUPLE DAYS HAVE BEEN MIXED... WITH
THE PAST 24 HRS LEANING SLOWER. GIVEN A WEAKER CONSENSUS THAN THE
NAM BY F36 LATE SAT... PREFER A COMPROMISE AMONG THE GFS AND OTHER
NON-NAM SOLNS TO RESOLVE THESE CONTINUED DETAIL AND CONTINUITY
DIFFS.
..TROF LIFTING AWAY FROM THE EAST
THE GFS AND NAM OFFER SIMILAR SOLNS WITH THE EVOLUTION OF MID LVL
FLOW AND DEEPENING SFC LOW PRESSURE TRACKING FROM THE WRN ATLC
INTO EXTREME ERN CANADA. ASIDE FROM MINOR STRENGTH/DETAIL
DIFFS... REMAINING 12Z MODELS AND ENSEMBLE GUIDANCE OFFERS
REASONABLE SUPPORT FOR THE GFS/NAM SCENARIO.
...MODEL TREND GRAPHICS AT
WWW.HPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML...
...500 MB FORECASTS AT
WWW.HPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML...
RAUSCH
Q%
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