528
FXUS10 KWNH 210622
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
221 AM EDT THU MAY 21 2020
VALID MAY 21/0000 UTC THRU MAY 24/1200 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION INCLUDING PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..CUT-OFF LOW OVER LOWER OH AND TN RIVER VALLEYS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND...THROUGH 60 HOURS
NON-GFS BLEND...AFTER 60 HOURS
CONFIDENCE: ABOVE AVERAGE
OVERALL, THE 00Z NAM/GFS SOLUTIONS AND THE 00Z NON-NCEP MODELS ARE
IN GOOD AGREEMENT WITH THE DETAILS OF THE CUT-OFF UPPER LOW
CURRENTLY OVER THE TN VALLEY WHICH SHOULD LIFT NORTH THROUGH THE
OH VALLEY ON FRIDAY BEFORE TURNING EAST ACROSS THE NORTHERN
MID-ATLANTIC REGION ON SATURDAY. HOWEVER, GRADUALLY THE GFS BEGINS
TO ACCELERATE THE SYSTEM OFFSHORE A TAD FASTER THAN THE REMAINING
GUIDANCE AND THE LATEST ENSEMBLE MEANS AFTER 60 HOURS. WILL PREFER
A GENERAL MODEL BLEND THROUGH 60 HOURS, AND THEN A NON-GFS BLEND
AFTER 60 HOURS AS THE SYSTEM MOVES OFFSHORE AND OUT TO SEA.
..DEEP UPPER TROUGH/CLOSED LOW OVER THE NORTHERN ROCKIES
..SECONDARY UPPER TROUGH OVER THE PACIFIC NORTHWEST BY THURSDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND...THROUGH 60 HOURS
NON-UKMET BLEND...AFTER 60 HOURS
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
THE LATEST GUIDANCE SHOWS VERY GOOD AGREEMENT IN TAKING THE UPPER
TROUGH AND ASSOCIATED CLOSED LOW OVER THE NORTHERN ROCKIES
NORTHWARD INTO SOUTHWEST CANADA OVER THE NEXT 24 HOURS. AS THIS
OCCURS, A NEW UPPER TROUGH AND ASSOCIATED CLOSED LOW WILL BE
ADVANCING SOUTHEAST IN ACROSS THE PACIFIC NORTHWEST. THIS ENERGY
WILL RELOAD A FULL-LATITUDE TROUGH ACROSS THE WEST BY SATURDAY. BY
SUNDAY, THE TROUGH WILL BEGIN TO EDGE EAST TOWARD THE PLAINS. THE
MODELS ARE IN GOOD MASS FIELD AGREEMENT THROUGH ABOUT 60 HOURS,
BUT THEREAFTER THE 00Z UKMET IS A BIT MORE OUT OF PHASE WITH THE
OTHER DETERMINISTIC MODELS, ESPECIALLY WITH ITS CLOSED MID-LEVEL
LOW CENTER OVER WESTERN WY AT THE END OF THE PERIOD. THE UKMET IS
ALSO PERHAPS STILL JUST A TAD TOO SLOW IN ADVANCING ENERGY OFF TO
THE EAST TOWARD THE PLAINS. THIS SLOWER EVOLUTION IS ALSO EVIDENT
AT THE SURFACE, AS THE UKMET IS A TAD SLOWER THAN THE REMAINING
MODELS WITH ITS FRONTAL EVOLUTION. SO, WILL PREFER A GENERAL MODEL
BLEND THROUGH 60 HOURS, AND THEN A NON-UKMET BLEND THEREAFTER.
..SHORTWAVE LIFTING NORTHEAST ACROSS THE MIDWEST BY LATE FRIDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-UKMET BLEND
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 UKMET IS
THE WEAKEST SOLUTION WITH THIS ENERGY. THE REMAINING GUIDANCE IS
REASONABLY WELL CLUSTERED, AND SO A NON-UKMET BLEND 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
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