908
FXUS10 KWNH 291716
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1216 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 GFS AND 00Z 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 00Z UKMET/CMC SOLUTIONS ARE CONSIDERABLY FASTER WITH
THIS ENERGY THAN THE REMAINING SUITE OF GUIDANCE. HOWEVER, THE 12Z
NAM IS QUITE SLOW, WITH THE 12Z GFS/00Z ECMWF SOLUTIONS IN BETWEEN
FASTER AND SLOWER CAMPS. BASED ON THE LATEST ENSEMBLE GUIDANCE, A
BLEND OF THE 12Z GFS AND 00Z ECMWF 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
06Z GEFS MEAN...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
TRENDING 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 00Z ECMWF IS THE SLOWEST SOLUTION BY
THIS TIME FRAME, WITH THE 00Z UKMET ONLY SLIGHTLY FASTER. THE 00Z
CMC IS IN BETWEEN THE UKMET AND GFS SOLUTIONS, BUT SUGGESTS MORE
OF AN OPEN TROUGH VERSUS A CLOSED LOW AS THE MODEL CONSENSUS
FAVORS AT THE END OF THE PERIOD. THE CMC TIMING THOUGH IS VERY
CLOSE TO THE MODEL CONSENSUS, AND IS SUPPORTED BY THE 06Z GEFS
MEAN AS WELL. THE 00Z ECENS MEAN IS LIKELY TOO SLOW (LIKE THE
ECMWF). GIVEN THAT THE 06Z GEFS MEAN IS CLOSEST TO THE MODEL
CONSENSUS BY THE END OF THE PERIOD, AND THE GLOBAL MODELS HAVE
BEEN TRENDING TOWARD IT, THE GEFS MEAN WILL BE PREFERRED BY THE
END OF THE PERIOD. 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 SOUTHWEST, WITH THE GEFS MEAN 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
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