Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1232 PM EDT Fri Jul 19 2019

Valid Jul 19/1200 UTC thru Jul 23/0000 UTC

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

12Z Prelim Model Evaluation Including Preference and Confidence
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...Overall Pattern Across the CONUS...
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Preference: General model blend;
            Less weight on GFS, NAM, CMC by Monday
Confidence: Average

Models are in generally good agreement across most of the CONUS
for the next few days with similar mass field forecasts. The ECMWF
Ensemble spread for 500mb heights is generally below the previous
30-day average. One area of greater variability is with the
digging trough into the Great Lakes region on Sunday and Monday.

The 12Z GFS and 12Z NAM show more amplification with the digging
trough. With respect to the degree of amplification, the GFS is
only joined by a few GEFS members, but the vast majority of the
ensemble distribution is less amplified. The NAM is fairly similar
to the GFS, and thus given a lack of ensemble support, less weight
will be placed on those models by Day 3 (Monday). Meanwhile, the
00Z CMC shows a faster progression to the surface cold front, and
by Day 3 differs in placement of QPF more substantially. Less
weight was also placed on the CMC at those time ranges.

Through most of the forecast, a blend of the 00Z UKMET and 00Z
ECMWF offers a reasonable blend, and incorporation of the GFS, NAM
and CMC seems reasonable over the weekend.


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

Lamers