878
FXUS10 KWNH 281850
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
249 PM EDT TUE JUL 28 2020
VALID JUL 28/1200 UTC THRU AUG 01/0000 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION INCLUDING PRELIMINARY PREFERENCES AND
FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..MID-UPPER LEVEL TROUGHING OVER THE GREAT LAKES AND NORTHEAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: AVERAGE
ONLY MINOR TIMING DIFFERENCES WERE NOTED WITH THE MID-LEVEL CLOSED
LOW/TROUGH THAT SLOWLY MOVES EAST INTO THE NORTHEASTERN U.S. OVER
THE ENXT FEW DAYS. SIMILARLY WITH THE RELATED COLD FRONT AT THE
SURFACE, DIFFERENCES ARE RELATIVELY MINOR WITH THE POSITION WITH
THE DETERMINISTIC AND ENSEMBLE GUIDANCE SHOWING REASONABLE
AGREEMENT REGARDING THIS SYSTEM. NO SIGNIFICANT ADJUSTMENTS WERE
NOTED WITH THE 12Z ECMWF/UKMET/CMC COMPARED TO THEIR PREVIOUS 00Z
CYCLES.
..MID-LEVEL ENERGY OVER GREAT BASIN
...ENERGY ADVANCING SOUTHEAST ACROSS THE PLAINS FOR
WEDNESDAY/THURSDAY...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON 12Z UKMET BLEND
CONFIDENCE: AVERAGE
A MID-LEVEL OVER WESTERN WYOMING TODAY IS EXPECTED TO REACH THE
GREAT PLAINS BY THURSDAY MORNING, WHICH WHEN COMBINED WITH SMALLER
SCALE DISTURBANCES NEARBY RESULTS IN A LONGWAVE TROUGH OVER THE
CENTRAL U.S. BY THE END OF THE WEEK. ONLY THE 12Z UKMET DIFFERED
SIGNIFICANTLY FROM THE REMAINING DETERMINISTIC CONSENSUS AND
ENSEMBLE MEANS, WITH THE UKMET NOTED TO BE FASTER WITH THE MAIN
MID-LEVEL SHORTWAVE REACHING THE PLAINS. THE PREVIOUS 00Z UKMET
WAS STRONGER AND SLOWER ALOFT. OTHERWISE, ENSEMBLE SPREAD IS
AVERAGE FOR THE CENTER OF THE U.S. BY FRIDAY EVENING. WHILE THE
12Z UKMET IS NOT AN OUTLIER, IT FALLS WITHIN THE MINORITY OF THE
AVAILABLE ENSEMBLE GUIDANCE.
AT THE SURFACE, A LOW ALONG A SLOW MOVING FRONTAL BOUNDARY WILL
IMPACT THE CENTRAL/SOUTHERN PLAINS INTO THE MISSISSIPPI VALLEY.
ENSEMBLE SCATTER LOW PLOTS DEPICT SIGNIFICANT SPREAD IN LATITUDE
AND LONGITUDE BY 00Z/01 WITH EVEN THE STRONGER 12Z NAM WITHIN THE
CLUSTERING AND NOT UNREASONABLE.
..UPPER LOW/TROUGH APPROACHING THE PACIFIC NORTHWEST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: AVERAGE
SIMILAR TO THE MID-UPPER LEVEL TROUGH IMPACTING THE NORTHEAST,
THERE IS REASONABLY GOOD AGREEMENT WITH THE CLOSED LOW ADVANCING
EAST TOWARD THE PACIFIC NORTHWEST THURSDAY AND FRIDAY. THERE ARE
SOME MINOR TIMING DIFFERENCES WITH THE 12Z NAM SLOWEST AND 12Z
UKMET FASTEST, BUT ALL OF THE DETERMINISTIC MODELS ARE CLOSE
ENOUGH TO SUPPORT A GENERAL MODEL BLEND FOR THIS SYSTEM. ONLY
MINOR TIMING DIFFERENCES WERE NOTED WITH THE 12Z ECMWF/UKMET/CMC
COMPARED TO THEIR PREVIOUS 00Z CYCLES.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
THIS PRODUCT WILL TERMINATE AUGUST 15, 2020:
WWW.WEATHER.GOV/MEDIA/NOTIFICATION/PDF2/SCN20-58PMDHMD_TERMINATION.
OTTO
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