Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
257 PM EDT Wed Oct 02 2019

Valid Oct 02/1200 UTC thru Oct 06/0000 UTC

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

12Z Model Evaluation with Preferences and Forecast Confidence
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...Overall Pattern Across the CONUS...
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Preference: General Model Blend
Confidence: Above Average

19Z Update: No significant changes noted with the rest of the 12Z
guidance. The ECMWF came in a bit more amplified with the
approaching trough on Day 3 in the northwest and northern Rockies,
but its differences were not significant enough to not include.
The UKMET trended slower and now is more aligned with the rest of
the guidance, so it can be incorporated more on Day 3. With this
in mind, a general model blend can be applied through all 3 days.

---previous discussion---
Relatively good agreement in the model guidance through Day 2
across the CONUS. The synoptic pattern is expected to transition
to more zonal flow as the highly amplified trough west / ridge
east pattern breaks down. By Day 3, another longwave trough is
expected to move onshore the Pacific Northwest and then across the
interior northern Rockies. This is where the greatest model
differences are noted.

The 00Z UKMET is the biggest outlier compared to the rest of the
deterministic and ensemble guidance. Its trough axis is more
negatively tilted and faster (bringing its axis through ND by Day
3). Also the 12Z NAM is a bit faster and more amplified. There is
relatively good agreement between the ECMWF/CMC/GFS on axis and
position through Day 3 and has support from associated ensemble
members. Elsewhere across the CONUS, surface high pressure will
generally dominate the eastern US while by the end of Day 3,
southerly return and surface cyclogenesis takes place in the
central Plains.

With the above average consistency and model pattern through Day
2, a general model blend can be applied. For Day 3, and
specifically the northwest and interior northern Rockies, more
weight/inclusion of the ECMWF/CMC/GFS is preferred.


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

Taylor