431
FXUS10 KWNH 131701
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
100 PM EDT MON JUL 13 2020
VALID JUL 13/1200 UTC THRU JUL 17/0000 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION WITH PRELIMINARY PREFERENCES/CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...MID-LEVEL SHORTWAVE TROUGHING OVER THE NORTHEASTERN QUARTER OF
THE U.S. MONDAY TO WEDNESDAY...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: AVERAGE
THE 12Z NCEP GUIDANCE MAINTAINED GOOD RUN TO RUN CONTINUITY WITH
THIS FEATURE, IN TERMS OF THE DEPTH AND THE SPEED OF THE SYSTEM.
THIS LEFT THE 13/00Z ECMWF AND UKMET A BIT ON THE SLOWER SIDE OF
THE DETERMINISTIC GUIDANCE. GIVEN THE SMALL DIFFERENCES, A
GENERAL MODEL BLEND WILL WORK FINE ALTHOUGH A BIT LESS WEIGHT
SHOULD BE GIVEN TO THE SLOWER ECMWF/UKMET.
...LONGWAVE TROUGH AXIS MOVING THROUGH THE NORTH-CENTRAL U.S.
THROUGH WEDNESDAY WITH ACCOMPANYING SURFACE COLD FRONT...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 13/12Z GFS/NAM AND 13/00Z ECMWF/12Z CMC BLEND
CONFIDENCE: AVERAGE
THE 12Z NCEP GUIDANCE MAINTAINED GOOD RUN TO RUN CONSISTENCY HERE,
TOO, WITH A BROAD 500 MB TROUGH AND ASSOCIATED SURFACE COLD FRONT
MOVING ACROSS THE CENTRAL TO NORTHERN PLAINS LATER TONIGHT INTO
TUESDAY. SOME MINOR TIMING AND AMPLITUDE DIFFERENCES CONTINUE TO
BE SEEN, WITH THE 13/12Z GFS A BIT FASTER AND STRONGER WITH
MID-LEVEL HEIGHT FALLS ACROSS THE UPPER MIDWEST INTO THE WESTERN
GREAT LAKES REGION. AT THE SURFACE, THE NCEP GUIDANCE CONTINUED TO
BE MORE PROGRESSIVE THAN THE ECMWF AND UKMET...AND THE NCEP
GUIDANCE ALSO TENDED TO DEVELOP A WAVE ALONG THE FRONT IN
IOWA/ILLINOIS/WISCONSIN WHILE THE NON-NCEP GUIDANCE HAD LITTLE OR
NO SUCH DEVELOPMENT. BASED ON THE FACT THAT THE MODELS TENDED TO
SHOW A SPEED MAX AT JET LEVEL AIDING UPPER LEVEL DIVERGENCE OVER
THAT REGION, AM INCLINED TO FAVOR THE NCEP GUIDANCE. PERHAPS THE
GFS IS TOO AGGRESSIVE HERE, ESPECIALLY LOOKING AT THE THERMAL
FIELDS IN LOW LEVELS, BUT NOT ENOUGH TO DISCOUNT ITS SOLUTION.
..CUT OFF LOW WEST OF CALIFORNIA BY THURSDAY MORNING
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: AVERAGE
GOOD MODEL AGREEMENT EXISTS WITH A 700-500 MB LOW CLOSING OFF BY
MID-WEEK FROM A WEAK AND NEARLY STATIONARY TROUGH AXIS IN PLACE
OVER THE WESTERN U.S. TODAY. THE LATEST GUIDANCE SHOWS VERY LITTLE
IN THE WAY OF DIFFERENCES WITH THE TIMING, PLACEMENT AND STRENGTH
OF THIS FEATURE. THEREFORE, A GENERAL MODEL BLEND WILL BE USED FOR
THE PREFERENCE.
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.
BANN
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