763
FXUS10 KWNH 260656
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
255 AM EDT FRI JUN 26 2020
VALID JUN 26/0000 UTC THRU JUN 29/1200 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION INCLUDING PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
CLOSED LOW OVER QUEBEC
TROUGH IMPACTING THE NORTHEAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-NAM BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
THE MODELS ARE IN GOOD AGREEMENT ON THE DETAILS OF THE LARGE
CLOSED LOW OVER QUEBEC AND SOUTHWARD EXTENSION OF THE TROUGH
ACROSS THE NORTHEAST U.S. GOING THROUGH SATURDAY. HOWEVER, BY
SUNDAY, THE MODELS SUGGEST A NEW SHORTWAVE TROUGH WILL CROSS THE
GREAT LAKES AND HELP TO AMPLIFY THE TROUGHING OVER THE NORTHEAST
WITH SOME SOUTHWARD ADVANCE OF THE CLOSED LOW AS WELL. THE 00Z NAM
IS MORE AGGRESSIVE WITH THIS ADDITIONAL ENERGY AND RESULTS IN A
SOMEWHAT STRONGER CLOSED LOW AND LARGE SCALE TROUGH INVOLVING THE
NORTHEAST BY THE END OF THE PERIOD. WILL PREFER A NON-NAM BLEND
FOR NOW GIVEN GOOD GLOBAL MODEL AGREEMENT/CLUSTERING OTHERWISE.
DEEP UPPER TROUGH/CLOSED LOW DIGGING INTO THE WEST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-NAM BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
A DEEP UPPER TROUGH AND ASSOCIATED CLOSED LOW IS FORECAST TO
AMPLIFY INTO THE WEST THIS WEEKEND WITH THE MODELS SUPPORTING A
STRONG UPPER LOW OVER SOUTHWEST ID BY EARLY MONDAY. THE GLOBAL
MODELS ARE ACTUALLY IN VERY GOOD AGREEMENT OVERALL WITH THE
PLACEMENT AND DEPTH OF THE SYSTEM. THE 00Z NAM THOUGH FOR ITS PART
IS A BIT DEEPER AND COLDER THAN THE GLOBAL MODELS AND IS A MODEST
OUTLIER AS A RESULT, BUT ITS POSITIONING IS OTHERWISE CLOSE TO THE
GLOBAL MODEL CONSENSUS. WILL PREFER A NON-NAM BLEND FOR THE CLOSED
LOW FOR THE TIME BEING.
SHORTWAVES LIFTING NORTHEAST OVER THE PLAINS/MIDWEST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z ECMWF/GEFS MEAN AND 12Z ECENS MEAN
CONFIDENCE: SLIGHTLY BELOW AVERAGE
AHEAD OF THE DEEP WESTERN U.S. TROUGH/CLOSED LOW WILL BE A PARADE
OF SHORTWAVE TROUGHS THAT EJECT NORTHEAST OUT OF THE SOUTHWEST AND
ACROSS THE PLAINS AND MIDWEST. THE 00Z NAM IS OVERALL THE DEEPEST
SOLUTION WITH THIS ENERGY. THE 00Z GFS TENDS TO BE MORE
PROGRESSIVE WITH THE SHORTWAVES VERSUS THE 00Z UKMET/ECMWF
SOLUTIONS AND ESPECIALLY THE 00Z CMC WHICH IS THE SLOWEST. THE 00Z
GEFS MEAN AND 12Z ECENS MEAN ACTUALLY CLUSTER TOGETHER QUITE WELL
AND SUGGEST A SOLUTION IN BETWEEN SLOWER AND FASTER CAMPS, AND AS
A CLUSTER APPEAR TO BE AT LEAST REASONABLY SUPPORTIVE OF THE
ECMWF. SO A BLEND OF THE ECMWF, GEFS MEAN AND ECENS MEAN WILL BE
PREFERRED AT THIS TIME. GIVEN THE SPREAD IN THE DETERMINISTIC
GUIDANCE THOUGH WITH TIMING AND DEPTH OF THIS ENERGY, CONFIDENCE
REMAINS A BIT LIMITED.
REMNANT ENERGY ACROSS THE LOWER MS VALLEY
WEAKNESS LINGERING OVER TEXAS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
THE MODEL SUPPORT A GRADUAL BUILDING OF THE SUBTROPICAL RIDGE THIS
WEEKEND ACROSS THE FL PENINSULA AND ADJACENT AREAS OF THE GULF
COAST STATES. SOME OF THE WEAK SHORTWAVE ENERGY LINGERING OVER THE
LOWER MS VALLEY WILL ESSENTIALLY SHEAR OUT OVER TOP OF THE RIDGE
OVER THE NEXT COUPLE OF DAYS. HOWEVER, THERE WILL STILL BE A
FAIRLY BROAD MID-LEVEL WEAKNESS/TROUGH LINGERING OVER TEXAS WHICH
SHOULD TEND TO RETROGRADE WESTWARD THROUGH SATURDAY BEFORE THEN
LIFTING NORTH THROUGH THE SOUTHERN AND CENTRAL PLAINS AHEAD OF THE
DEEP WESTERN U.S. TROUGH/CLOSED LOW. A GENERAL MODEL BLEND WILL BE
PREFERRED WITH THE ENERGY OVER TEXAS AND THE LOWER MS VALLEY.
UPPER TROUGH/LOW OVER MANITOBA/SASKATCHEWAN
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF 00Z CMC AND 00Z ECMWF
CONFIDENCE: AVERAGE
A SEPARATE CLOSED LOW AND ASSOCIATED TROUGH OVER SOUTHWEST CANADA
WILL DRIVE DEEPENING SURFACE LOW PRESSURE OVER AREAS OF MANITOBA
AND SASKATCHEWAN GOING THROUGH SATURDAY AND SUNDAY. THE 00Z NAM
APPEARS TOO DEEP WITH ITS HEIGHT FALLS, AND THE 00Z UKMET APPEARS
TOO FAST IN ADVANCING ITS ENERGY OFF TO THE NORTHEAST. MEANWHILE,
THE 00Z NAM/GFS SOLUTIONS ARE BOTH ON THE SLOWER SIDE OF THE
GUIDANCE, WITH THE LATEST ENSEMBLE MEANS A BIT MORE SUPPORTIVE OF
THE 00Z CMC/ECMWF CLUSTERING. THE CMC AND ECMWF ARE CLOSE TO THE
MODEL CONSENSUS, 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
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