Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
250 PM EDT Tue Jul 17 2018

Valid Jul 17/1200 UTC thru Jul 21/0000 UTC

...See NOUS42 KWNO (ADMNFD) for the status of the upper air
ingest...

12Z Final Model Evaluation...with Preferences and Confidence
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

...Overall Model Analysis for the CONUS...

Overall Preference: General compromise through 00Z Thursday, then
non-NAM compromise
General Confidence: Average

The deterministic and ensemble model guidance is in relatively
good agreement on the large scale pattern over the continental
U.S. through about 00Z Thursday.  Beyond that time, differences
begin to become more apparent with respect to the shortwave trough
amplifying over the Upper Midwest and Great Lakes.  The 12Z NAM is
exhibiting the most significant differences from model consensus
by being considerably stronger with the trough axis by Friday
morning, and therefore discounted from the preference beyond 00Z
Thursday.  Among the remaining guidance, the 12Z ECMWF is slightly
deeper than the model consensus with the same shortwave, but not
to the degree of the NAM. 

Therefore, the preference is for a blend of the
GFS/ECMWF/UKMET/CMC, which show reasonably good agreement and are
closest to the available ensemble means.  Forecast confidence is
considered average, and above average confidence for the building
upper level ridge over the western High Plains and extending to
the southwestern U.S. 


Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml

Hamrick