Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
123 PM EDT Sun Jul 21 2019

Valid Jul 21/1200 UTC thru Jul 25/0000 UTC

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

12Z Preliminary Model Evaluation, Including Preference and
Confidence
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...Much of the CONUS...
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Preference: General Model Blend
Confidence: Slightly Above Average

Models have come into better accord with respect to the eastward
progression of the amplifying eastern CONUS trough and associated
surface front. QPF discrepancies remain however, mainly
timing-based, and as such are not reflective of the solid model
consensus with the mass fields. UKMet for example is still on the
faster edges of the guidance spread with the pre-frontal QPF in
the eastern CONUS going into day 2, while the ECMWF remains the
slowest. Given the highly-favorable thermodynamic profile ahead of
the front and thus likely high convective contribution to the QPF
intensity and progression, would lean more toward a blend of the
high-res CAMs with in terms of the QPF on day 2, with a general
multi-model blend on day 3.

...Pacific NW...
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Preference: Non-NAM, Non-GFS Model Blend
Confidence: Above Average

The NAM remains flatter compared to the rest of the guidance with
respect to the shortwave pivoting through the PAC NW region late
Tue into Wed, and with the 12Z run has trended slower with this
feature. The GFS is a bit more amplified than the global guidance
mean, which is reflected by the heavier QPF across northeast
WA-northern ID-northwest MT on day 3.

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

Hurley