Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
231 PM EDT Sun Aug 04 2019

Valid Aug 04/1200 UTC thru Aug 08/0000 UTC

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

12Z Model Evaluation with Preferences and Confidence
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...Overall Pattern Across the CONUS...
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Preference: Blend of the 12Z GFS, 12Z CMC and 12Z ECMWF
Confidence: Above average

The synoptic pattern continues to look relatively consistent, with
a persistent ridge in the Western U.S. and a trough over the East
that gets reinforced by some digging shortwaves embedded within
deeper layer northwest flow aloft. Deterministic models are in
fairly good agreement, and ECMWF ensemble spread is below the
previous 30-day average in many areas -- indicating generally
better than average model similarity for mid-summer.

A blend of the 12Z GFS, 12Z CMC, and 12Z ECMWF is the preference
at this time across the CONUS. Differences among these models are
modest and they tend to have good ensemble support. A blend of
these should also resolve any smaller scale detail differences
relating to convective processes and smaller scale vort-maxima.

The 12Z NAM and 12Z UKMET remain a bit outside the envelope of
NAEFS and ECMWF ensemble height spread in some areas, mostly
surrounding the trough in the East on Tuesday and Wednesday. The
UKMET once again shows a stronger ridge over the Southwest than
any other deterministic model, and a less amplified trough in the
East, with minimal ensemble support. Meanwhile, the NAM shows a
stronger shortwave digging across portions of the Upper Midwest,
Great Lakes and OH Valley Tuesday into Wednesday. Given a lack of
ensemble support, these models are not included in the preference
at this time.


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

Orrison/Lamers