Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1244 AM EDT Mon Oct 21 2019

Valid Oct 21/0000 UTC thru Oct 24/1200 UTC

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

00Z Model Evaluation with Preferences and Confidence
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Deepening Central Plains cyclone; secondary low from Carolinas to
New England Tue-Wed.
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Preference: General model blend
Confidence: Slightly above average

Aloft, model spread has lessened and there is fairly tight
clustering with the latest mass fields with the mid/upper level
closed low currently over the central Plains. Over the next couple
of days it will lift through the Upper Midwest and into portions f
western Ontario. At the surface, the low should generally maintain
its strength or drop about another ~10 mb over southern Minnesota,
after which the system becomes stacked and gradually fills as it
moves into western Ontario after 60 hours. A secondary area of low
pressure will develop across the Carolinas Tuesday evening and
lift northeast along the eastern U.S. coast. Again here the model
spread is fairly limited and there decent agreement with the 00Z
GFS/NAM with the earlier 12Z guidance. A general model blend is
preferred given the average to above average model agreement and
forecast confidence.


Stronger shortwave dropping through Rockies early to mid week
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: 00Z GFS with 12Z ECENS/GEFS means
Confidence: Slightly below average

A stronger, compact shortwave trough will drop through the
Canadian Rockies and into the Plains mid-week and with building
heights over the eastern/northeast Pacific, a more amplified upper
level pattern is expected to evolve over the western/central
CONUS. The fast moving clipper-like low has decent agreement with
primarily speed differences noted between the faster/stronger
UKMET and NAM. The GFS and ECMWF are a bit slower and weaker,
especially as the low reaches the Upper Midwest. At 500 mb, the
ECMWF digs the trough further south into the Four Corners region
that any of the other deterministic models (the UKMET is close)
and this is outside the ensemble mean spread a bit. With this in
mind, will favor the ECENS/GEFS means along with the 00Z GFS.


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

Taylor