361
FXUS10 KWNH 221621
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1220 PM EDT MON JUN 22 2020
VALID JUN 22/1200 UTC THRU JUN 26/0000 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION INCLUDING PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
CLOSED LOW OVER ONTARIO/QUEBEC
SHORTWAVES OVER THE LOWER MS/OH VALLEYS...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-UKMET BLEND
CONFIDENCE: AVERAGE
THE LARGE CLOSED UPPER LEVEL LOW OVER WESTERN ONTARIO WILL ADVANCE
GRADUALLY EAST OVER THE NEXT COUPLE OF DAYS INTO QUEBEC AS A
LARGER SCALE TROUGH EXTENDING SOUTH FROM THIS CROSSES THE MIDWEST,
GREAT LAKES AND OH VALLEY. MEANWHILE, SEPARATE CONVECTIVE ENHANCED
VORTS/SHORTWAVES WILL EJECT ACROSS THE LOWER MS VALLEY AND THE OH
VALLEY GENERALLY AHEAD OF THE LARGER SCALE HEIGHT FALLS. MODEL
MASS FIELD SPREAD IS LARGELY MINIMAL WITH THESE SHORTWAVES AS THEY
LIFT NORTHEAST OVER THE NEXT 24 HOURS AND BEGIN TO DAMPEN OUT.
REGARDING THE DEEPER LAYER TROUGH AND CLOSED LOW, THE MODELS SHOW
RELATIVELY GOOD AGREEMENT WITH SOME MODEST SPATIAL AND DEPTH
SPREAD WITH THE HEIGHT FALLS AND THE SURFACE LOW REFLECTION.
TOWARD THE END OF THE PERIOD, THE 00Z UKMET BECOMES A BIT WEAKER
AND FASTER WITH THE CLOSED LOW EVOLUTION, AND APPEARS A TAD MORE
OUT OF TOLERANCE WITH THE SURFACE LOW REFLECTION OVER SOUTHEAST
CANADA. THEREFORE, A NON-UKMET BLEND WILL BE PREFERRED.
TROUGHS APPROACHING BRITISH COLUMBIA AND PACIFIC NORTHWEST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-GFS BLEND
CONFIDENCE: AVERAGE
A PAIR OF SHORTWAVE TROUGHS WILL APPROACH THE PACIFIC NORTHWEST
OVER THE NEXT COUPLE OF DAYS, THE FIRST IMPACTING MAINLY BRITISH
COLUMBIA THROUGH TONIGHT. A SECOND, STRONGER SHORTWAVE TROUGH DIGS
ACROSS THE PACIFIC NORTHWEST MID-WEEK AND EDGES INTO THE
INTERMOUNTAIN REGION BY THURSDAY. MODEL SPREAD IS MINIMAL WITH THE
FIRST IMPULSE. HOWEVER, THE 00Z NON-NCEP MODELS LED BY THE UKMET
ARE ALL A LITTLE FASTER THAN THE 12Z NAM/GFS SOLUTIONS WITH TIMING
OF THE SECOND SHORTWAVE TROUGH. THE GFS IS ALSO A TAD DEEPER THAN
THE REMAINING GUIDANCE. FOR NOW, A NON-GFS BLEND WILL BE PREFERRED
GIVEN BETTER ENSEMBLE SUPPORT FOR THE NON-GFS MODEL CONSENSUS.
MID-LEVEL ENERGY LINGERING OVER THE LOWER MS VALLEY/TEXAS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 12Z GFS AND 00Z ECMWF
CONFIDENCE: AVERAGE
THE MODELS SUGGEST SOME OF THE CONVECTIVELY DRIVEN SHORTWAVE
ENERGY LINGERING OVER THE LOWER MS VALLEY OVER THE NEXT COUPLE OF
DAYS WHICH WILL TEND TO SEPARATE OUT FROM THE WESTERLIES AND MAY
ACTUALLY TEND TO RETROGRADE WESTWARD. THE 12Z NAM AND 00Z CMC BOTH
APPEAR TO BE A BIT TOO STRONG WITH THE MID-LEVEL ENERGY. THE
BETTER MODEL CLUSTERING TENDS TO BE WITH THE 12Z GFS AND 00Z ECMWF
WITH THIS ENERGY, AND SO A BLEND OF THESE SOLUTIONS WILL BE
PREFERRED.
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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