Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
243 PM EDT Fri Aug 03 2018

Valid Aug 03/1200 UTC thru Aug 07/0000 UTC

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

12Z Model Evaluation Including Preference and Forecast Confidence
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...Overall Synoptic Pattern across the CONUS...
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Preference: General model blend, but with less weight given to the
NAM and UKMET across the central Plains to upper Midwest Sun to
Mon.
Confidence:  Average to above average

Overall, the models show fairly good agreement and run-to-run
continuity with the larger scale features across the CONUS,
southern Canada and the adjacent waters.  This includes the upper
trough lifting out of the eastern CONUS Fri to Sun, as well as the
deep upper low dropping south over the eastern Pacific.  The NAM
has backed off on the amplitude of the shortwave trough emanating
from the western CONUS, lifting northeast across the central Plain
to upper Midwest Sat to Sun - putting it into better agreement
with the model consensus.  Guidance does begin to diverge on Mon
with respect to an upper trough comprised of converging streams
over the northern Plains on Sunday.  The NAM and UKMET indicate a
little more phasing and in turn hold the trough axis further to
the west across the northern Plains to the upper Midwest late Sun
into Mon.  With the deterministic GFS and ECMWF, as well as their
ensemble means, supporting something more progressive, recommend
giving less weight to the slower solutions.

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

Pereira