Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1222 AM EDT Sun Jun 30 2019

Valid Jun 30/0000 UTC thru Jul 03/1200 UTC

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

00Z Model Evaluation...with Confidence and Preferences
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...Overall Pattern Across the CONUS...
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Preference: Non-NAM blend
Confidence: Slightly above average

Models are in good agreement with the synoptic pattern and their
mass fields are relatively similar. The largest differences are
with the 00Z NAM. By Tuesday, the NAM starts to move out of phase
with the other models with the trough in the Northwest. It also
shows very strong convectively induced vorticity maxima moving
east from Colorado into the central Plains, which has a
substantial impact on QPF. These differences have limited ensemble
support, so the NAM is excluded from the model preference.

There are some other differences with QPF from the Plains into the
Upper Midwest. Latitudinal position of the band of heavy rain in
the Upper Midwest does have some variability among the models, and
the GFS was given less weight in that region given a front
position that is less similar to the non-NCEP models. In the
southern and central Plains, an upper level low is expected to
drift north. The NAM and GFS show more QPF associated with this,
while the non-NCEP models are relatively dry. This may be
partially due to the NAM and GFS propagating some MCVs east from
Colorado, but a wetter scenario cannot be ruled out given the
presence of the upper low. A non-NAM blend in the central Plains
is preferred.


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

Lamers