Prognostic Meteorological Discussion
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FXUS10 KWNH 291849
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
248 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 MODEL EVALUATION INCLUDING FINAL PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


MID-LEVEL TROUGHING TRACKING ACROSS THE MID-MISS VALLEY TODAY AND
  GREAT LAKES REGION SAT/SUN
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z GFS / 12Z 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 12Z UKMET REMAINS STRONGER AND ENDS UP TOWARD THE FASTER EDGE
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.
THE 12Z ECMWF/UKMET/CMC DO SHOW SOME WEAKER TRENDS SO PERHAPS
CONVERGENCE IS BEGINNING TO OCCUR. 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 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 / 12Z ECMWF BLEND
CONFIDENCE: AVERAGE

THE 12Z NAM/UKMET ARE STRONGER WITH THE MID-LEVEL CORE OF THIS
SYSTEM AND 12Z GFS WEAKER BUT THE MODELS ALL HAVE SIMILAR TIMING.
GIVEN THESE DIFFERENCES MAINLY IMPACT CANADA AND THE 12Z 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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