312
FXUS10 KWNH 220417
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1216 AM EDT FRI MAY 22 2020
VALID MAY 22/0000 UTC THRU MAY 25/1200 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION INCLUDING PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..CUT-OFF LOW IMPACTING THE OH VALLEY AND NORTHERN MID-ATLANTIC
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-NAM BLEND
CONFIDENCE: ABOVE AVERAGE
OVERALL, THE GLOBAL MODELS ARE IN VERY GOOD AGREEMENT WITH THE
DETAILS OF THE CUT-OFF UPPER LOW DRIFTING NORTH NOW OVER THE OH
VALLEY WHICH SHOULD TURN EAST ACROSS THE NORTHERN MID-ATLANTIC
REGION BY SATURDAY AND THEN HEAD OFFSHORE. THE 00Z NAM RATHER
EARLY IN THE PERIOD BECOMES SLOWER THAN ALL OF THE GLOBAL MODELS
IN ADVANCING THE SYSTEM EASTWARD. WILL PREFER A NON-NAM BLEND
SINCE THE GLOBAL MODELS ARE TIGHTLY CLUSTERED IN AGREEMENT.
..DEEP UPPER TROUGH/CLOSED LOW RELOADING OVER THE WESTERN U.S
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND...THROUGH 60 HOURS
NON-UKMET BLEND...AFTER 60 HOURS
CONFIDENCE: AVERAGE
THE LATEST GUIDANCE SHOWS VERY GOOD AGREEMENT IN BRINGING A NEW
LARGE SCALE UPPER TROUGH AND ASSOCIATED CLOSED LOW IN ACROSS THE
PACIFIC NORTHWEST AND THROUGH THE INTERMOUNTAIN WEST BY THIS
WEEKEND. BY EARLY NEXT MONDAY, THE CONSENSUS OF GUIDANCE SUPPORTS
A DEEP TROUGH EDGING TOWARD THE PLAINS WITH A CLOSED LOW CENTER
MOST LIKELY OVER THE CENTRAL ROCKIES. MODEL MASS FIELDS ARE IN
GOOD AGREEMENT UNTIL ABOUT 60 HOURS WHEN THE 12Z UKMET SUGGESTS
THE CLOSED LOW FOCUSING FARTHER NORTH UP ACROSS WY, WHERE AS THE
REMAINING GUIDANCE SUGGESTS IT WILL BE DOWN OVER WESTERN OR EVEN
SOUTHWEST CO. THE LATEST GEFS MEAN AND ECENS MEAN FAVOR THE MORE
SOUTHERLY POSITION BY THE END OF THE PERIOD, AND ACTUALLY EVEN
SUGGEST THE 00Z GFS COULD BE A TAD TOO FAR NORTH AS THE 00Z
NAM/12Z CMC AND 12Z ECMWF ARE ALL A LITTLE FARTHER SOUTH WITH THE
ENSEMBLE MEANS. FOR NOW, WILL PREFER A GENERAL MODEL BLEND THROUGH
60 HOURS, AND A NON-UKMET BLEND THEREAFTER.
..SHORTWAVE LIFTING NORTHEAST ACROSS THE MIDWEST BY LATE FRIDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z GFS AND 12Z ECMWF
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
AHEAD OF THE DEEP LAYER TROUGHING OVER THE WESTERN U.S., THE
MODELS ALLOW A SHORTWAVE TROUGH TO LIFT NORTHEAST FROM THE
SOUTHERN HIGH PLAINS AND ACROSS THE MIDWEST BY LATE FRIDAY. THE
GUIDANCE FAVORS SOME AMPLIFICATION OF THIS SYSTEM WITH A CLOSED
MID-LEVEL LOW CENTER FORMING FRIDAY NIGHT OVER EASTERN NE AND THEN
LIFTING THROUGH THE UPPER MIDWEST ON SATURDAY. THE ENERGY WILL
THEN BEGIN TO WEAKEN OVER THE GREAT LAKES BY SUNDAY AS IT ATTEMPTS
TO CREST THE DEEP LAYER RIDGE FORMING AND NOSING NORTHWARD BY THEN
OVER THE OH/TN VALLEYS AND SOUTHEAST. OVERALL, THE 00Z NAM IS A
SLOWER AND SOMEWHAT DEEPER OUTLIER WITH THE ENERGY AS IT CROSSES
THE MIDWEST. ON THE FLIP SIDE, THE 12Z UKMET IS THE WEAKEST
SOLUTION AND ALSO A TAD MORE PROGRESSIVE THAN THE MODEL CONSENSUS.
THE BEST MODEL CLUSTERING AND ENSEMBLE SUPPORT FAVORS A SOLUTION
TOWARD A BLEND OF THE 00Z GFS AND 12Z ECMWF, AND SO A BLEND OF
THESE SOLUTIONS WILL BE PREFERRED WITH THIS SHORTWAVE.
..SHORTWAVE LIFTING NORTHEAST ACROSS THE SOUTHERN PLAINS SUNDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-CMC BLEND
CONFIDENCE: AVERAGE
AS THE DEEP TROUGH AND ASSOCIATED CLOSE LOW EVOLVES ACROSS THE
WEST THIS WEEKEND AND SLOWLY ENCROACHES ON THE HIGH PLAINS, THERE
WILL BE A SHORTWAVE TROUGH ROUNDING THE BASE OF IT AND LIFTING
NORTHEAST ACROSS THE SOUTHERN PLAINS ON SUNDAY. THE 12Z CMC IS A
TAD STRONGER THAN THE REMAINING GUIDANCE AND IS A BIT OUT OF
TOLERANCE WITH THE OTHER MODELS WITH ITS ENERGY LIFTING NORTH
ACROSS CENTRAL OK BY THE END OF THE PERIOD, AS THE REMAINING
MODELS AND ENSEMBLE MEANS SUPPORT MORE CONCENTRATION OF
ENERGY/TROUGHING DOWN OVER CENTRAL AND EASTERN TX. WILL RECOMMEND
A NON-CMC BLEND FOR THE TIME BEING.
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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