Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1231 PM EDT Tue Oct 29 2019

Valid Oct 29/1200 UTC thru Nov 02/0000 UTC

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

12Z Model Evaluation with Preferences and Confidence
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...Powerful closed low over the Intermountain West...
...Energy ejecting east across the Plains/Midwest Wednesday...
...Cold front/surface wave near OH/TN Valleys by Thursday...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: ECENS mean with ECMWF/UKMET/CMC blend
Confidence: Average to slightly below average after 31.12Z

Shortwave energy currently dropping through northern Rockies will
reach the Four Corners region Wednesday morning and close off at
500 mb. The wave then slowly tracks into the central Plains.
Through 48 hours (31.12Z), model agreement is average to above
average. However, as the positive tilted trough axis becomes more
negatively titled, the wave deepens over the Great Lakes region.
Here model differences become more noticeable. After being
considerably faster than the deterministic guidance previously,
the latest GFS now is on the slower side of the model envelope.
The NAM is much colder and therefore a bit deeper and further to
the northwest with its ULL position (as well the surface low).
Therefore, no to little inclusion of the NAM and deterministic GFS
is preferred. The rest of the guidance (UKMET/CMC/ECMWF) are all
in fairly good clustering and mirror the EC/GEFS means somewhat.
With that in mind, the WPC preference is for a EC/ECENS mean blend
incorporating the GEFS mean, CMC, UKMET as well.

...Next upper trough/front over the Plains by Friday...
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Preference: General model blend
Confidence: Above average

Another strong shortwave trough will quickly drop through the
longwave troughing over the Rockies and central Plains on Friday.
Model spread is minimal with this next system, so a general model
blend will be preferred for the time being.


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

Taylor