688
FXUS10 KWNH 291834
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
133 PM EST SAT FEB 29 2020
VALID FEB 29/1200 UTC THRU MAR 04/0000 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION WITH LATEST PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..DEEP UPPER TROUGH EXITING THE NORTHEAST TODAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
THE LATEST GUIDANCE SHOWS VERY GOOD AGREEMENT WITH THE DETAILS OF
THE DEEP TROUGH EXITING THE NORTHEAST LATER TODAY AND TONIGHT. THE
12Z NAM IS A TAD STRONGER THAN THE GLOBAL MODELS AS IT CLIPS
SOUTHERN NEWFOUNDLAND BY EARLY MONDAY, BUT A GENERAL MODEL BLEND
OTHERWISE BE PREFERRED.
..SHORTWAVE CROSSING THE UPPER MIDWEST/GREAT LAKES BY MONDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-GFS BLEND
CONFIDENCE: ABOVE AVERAGE
A SHORTWAVE AND ASSOCIATED COLD FRONT WILL CROSS THE UPPER MIDWEST
AND GREAT LAKES REGION SUNDAY NIGHT THROUGH MONDAY. THE 12Z GFS IS
A TAD STRONGER THAN THE REMAINING MODEL GUIDANCE WITH THE UPPER
TROUGH AND ALSO ITS SURFACE LOW REFLECTION AS IT CROSSES SOUTHERN
CANADA. GIVEN THE REASONABLY GOOD MODEL CLUSTERING/AGREEMENT SEEN
AWAY FROM THE GFS, A NON-GFS BLEND WILL BE PREFERRED.
..SHORTWAVE OVER THE NORTHERN PLAINS/MIDWEST BY TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-GFS BLEND
CONFIDENCE: ABOVE AVERAGE
A NEW NORTHERN STREAM SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT
WILL DROP ACROSS SOUTHERN CANADA AND DIG ACROSS THE NORTHERN
PLAINS AND MIDWEST BY TUESDAY. A SURFACE LOW CENTER WITH THIS
SYSTEM WILL CROSS SOUTHERN CANADA THROUGH THE PERIOD. THE 12Z GFS
IS GENERALLY A TAD MORE AMPLIFIED WITH THE UPPER TROUGH, AND ALSO
HAS ITS SURFACE LOW TRACK ON THE SOUTH SIDE OF THE MODEL SPREAD ON
TUESDAY. OVERALL, THE GFS IS A BIT OF AN OUTLIER RELATIVE TO THE
REMAINING GUIDANCE WHICH IS RATHER WELL CLUSTERED, SO A NON-GFS
BLEND WILL BE PREFERRED WITH THIS SYSTEM AS WELL.
..POSSIBLE SHORTWAVE NEAR THE PACIFIC NORTHWEST ON TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 12Z CMC/UKMET/ECMWF
CONFIDENCE: AVERAGE
THE GUIDANCE SUGGESTS A SHORTWAVE EMBEDDED WITHIN FAST UPSTREAM
PACIFIC FLOW WILL BE NEAR OR APPROACHING THE PACIFIC NORTHWEST ON
TUESDAY. THE 12Z NON-NCEP MODELS PER THE UKMET, CMC AND ECMWF HAVE
ALL CLUSTERED TOWARD A MORE PROGRESSIVE SOLUTION WITH ENERGY
ARRIVING ACROSS BRITISH COLUMBIA AND WASHINGTON STATE BY LATE
TUESDAY. THE 12Z NAM IS QUITE SLOW, WITH THE 12Z GFS FASTER BUT
SLOWER THAN THE NON-NCEP MODELS. GIVEN THE FAST AND RELATIVELY
ZONAL UPSTREAM PACIFIC FLOW, A BLEND OF THE MORE PROGRESSIVE
NON-NCEP MODELS WILL BE PREFERRED.
..DEEP TROUGH AMPLIFYING INTO THE SOUTHWEST SUNDAY/MONDAY
..ENERGY EJECTING EAST ACROSS THE SOUTHERN PLAINS TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-NAM BLEND...THROUGH 60 HOURS
12Z GEFS/00Z ECENS MEAN BLEND...AFTER 60 HOURS
CONFIDENCE: ABOVE AVERAGE...BECOMING AVERAGE AFTER 60 HOURS
THE MODELS AMPLIFY A SHORTWAVE TROUGH CROSSING THE PACIFIC
NORTHWEST TODAY AND SUPPORT A CLOSED LOW DROPPING SOUTH DOWN
ACROSS COASTAL AREAS OF CALIFORNIA ON SUNDAY. THEREAFTER, THE
ENERGY IS EXPECTED TO ADVANCE EAST ACROSS NORTHERN MEXICO AND THEN
EJECT OUT ACROSS THE RIO GRANDE VALLEY AND ADJACENT AREAS OF THE
SOUTHERN PLAINS ON TUESDAY. THE 12Z NAM IS OVERALL SOMEWHAT OF A
STRONGER OUTLIER WITH THIS SYSTEM THROUGH THE PERIOD, INCLUDING AS
IT TAKES THE SYSTEM OUT OVER THE SOUTHERN PLAINS. THE 12Z GFS HAS
TRENDED A LITTLE SLOWER THAN ITS PREVIOUS RUN, BUT IS STILL THE
MOST PROGRESSIVE SOLUTION AS THE ENERGY ARRIVES ACROSS THE RIO
GRANDE VALLEY ON TUESDAY. THE 12Z NON-NCEP MODELS ARE NOW ALL
TIGHTLY CLUSTERED ON A SLOWER SOLUTION OF THE CLOSED LOW TOWARD
THE END OF THE PERIOD, WITH THE UKMET AND ESPECIALLY THE CMC BOTH
TRENDING SLOWER WITH THIS RUN TO MATCH THE ECMWF. THE 00Z ECENS
MEAN STRONGLY SUPPORTS THIS SLOWER CAMP. THE 12Z GEFS MEAN IS
QUITE CONSISTENT WITH ITS PREVIOUS RUN IN BEING FASTER THAN THE
NON-NCEP MODEL CONSENSUS, BUT SLOWER THAN THE GFS. GIVEN THE
OVERALL SLOWER TREND SEEN WITH THE MODEL CONSENSUS COMPARED TO THE
PREVIOUS COUPLE OF MODEL CYCLES, A BLEND OF THE LATEST GEFS MEAN
AND ECENS MEAN WILL BE PREFERRED BY THE END OF THE PERIOD, WHICH
WILL YIELD A SLIGHT EDGE TO THE SLOWER CONSENSUS OF GUIDANCE AND
THUS A DISMISSAL OF THE GFS BY THAT POINT. MODEL CLUSTERING IS
GOOD FOR A NON-NAM BLEND TO BE PREFERRED THROUGH ABOUT 60 HOURS AS
THE SYSTEM CROSSES DOWN NEAR THE WEST COAST AND INTO SOUTHWEST,
WITH A GEFS/ECENS MEAN BLEND PREFERRED THEREAFTER AS IT APPROACHES
THE RIO GRANDE VALLEY.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
ORRISON
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