Prognostic Meteorological Discussion
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000
FXUS10 KWNH 291641
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1241 PM EDT FRI JUL 29 2016

VALID JUL 29/1200 UTC THRU AUG 02/0000 UTC

...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...

12Z NAM/GFS EVALUATION INCLUDING PRELIMINARY PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


MID-LEVEL TROUGHING TRACKING ACROSS THE MID-MISS VALLEY TODAY AND
  GREAT LAKES REGION SAT/SUN
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z GFS / 00Z ECMWF BLEND
CONFIDENCE: AVERAGE

THE MODELS SHOW REASONABLY GOOD AGREEMENT THROUGH SUN...AFTER
WHICH STRENGTH DIFFERENCES APPEAR WITH THE MID-LEVEL TROUGH
NOTICED BY MON MORNING OVER THE LOWER GREAT LAKES ALONG WITH SOME
TIMING DIFFERENCES.

THE 00Z UKMET IS CLEARLY MUCH STRONGER AND ENDS UP TOWARD THE
FASTER SIDE OF THE DETERMINISTIC SPREAD. GENERALLY THE NON-NCEP
GUIDANCE IS STRONGER HERE WITH THE LOW-MID LEVEL LOW WHILE THE 12Z
NAM/GFS ARE A BIT WEAKER...DESPITE HAVING TRENDED STRONGER SINCE
YESTERDAY. THESE DIFFERENCES AFFECT THE POSITION OF A SURFACE LOW
NEAR THE COAST OF THE NORTHEAST. GIVEN THE NAM IS SLIGHTLY SLOWER
THAN THE CONSENSUS...A BLEND OF THE SOMEWHAT SIMILAR 12Z GFS AND
00Z ECMWF APPEARS TO BE THE BEST MIDDLE GROUND FOR THIS SYSTEM
REGARDING POSITION AND STRENGTH.


LEAD SHORTWAVE TROUGH CLOSING OFF WHILE CROSSING SW CANADA LATE SAT
COLD FRONT CROSSING MONTANA
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z GFS / 00Z ECMWF BLEND
CONFIDENCE: AVERAGE

THE 12Z NAM AND 00Z UKMET ARE STRONGER WITH THE MID-LEVEL CORE OF
THIS SYSTEM BUT THE MODELS ALL HAVE SIMILAR TIMING. GIVEN THESE
DIFFERENCES MAINLY IMPACT CANADA AND THE 00Z ECMWF AND 12Z GFS
REPRESENT THE MIDDLE GROUND OF PLACEMENT DIFFERENCES IN THE CNTRL
PLAINS...A GFS/ECMWF BLEND IS PREFERRED.


SECOND CLOSED LOW REACHING THE PAC NORTHWEST MON
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: OPERATIONAL MODEL BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

ANY MODEL DIFFERENCES WITH THIS SYSTEM ARE RELATIVELY MINOR.

OTTO


...MODEL TREND GRAPHICS 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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