Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
109 AM EDT Wed Aug 14 2019

Valid Aug 14/0000 UTC thru Aug 17/1200 UTC

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

00Z Preliminary Model Evaluation with Preliminary Preferences and
Confidence
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...Overall Pattern Across the CONUS...
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Preference: 00Z GFS/12Z UKMET/12Z ECMWF and ECMWF/GEFS ensemble
means
Confidence: Slightly Below Average

The general synoptic evolution remains in very good agreement that
a ridge in the west and trough in the east will transition to
broad cyclonic flow with a weak trough or near zonal flow across
much of the CONUS. Overall the guidance is in better agreement
than the past several nights, with small scale features creating
the largest discrepancies over the forecast period.

The CMC remains the fastest with shortwaves rotating through the
quick flow across the northern tier, really faster than any other
available guidance and outside the ensemble envelope. The NAM is
also fast, but not nearly to the CMC speeds, and within the
envelope which could make it usable. However, the NAM is in
general too deep with each shortwave which impacts the QPF
bull's-eyes across the CONUS.

Of the preferred blend, each model has it's small discrepancies,
but not so much to make them unusable. The UKMET continues its
trend of being too high with heights across the CONUS, while the
ECMWF is a bit weak with dual shortwaves moving across the Rockies
and Central Plains. This leaves the GFS as the most reliable model
and should be weighted the most heavily in the blend, but will
continue to include a heavy portion of the ECENS and GEFS means as
well, both for continuity and to remove some of the uncertainty in
the smaller scale.


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

Weiss