Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
201 AM EST Wed Nov 07 2018

Valid Nov 07/0000 UTC thru Nov 10/1200 UTC

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

00Z Model Evaluation...with Preferences and Confidence
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

...Overall Pattern Across the CONUS...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: Blend of 00z GFS/ECMWF/UKMET
Confidence: Average

07z update: No significant changes to the preliminary preference.
The 00z ECMWF/UKMET continue to line up well with the 12z GFS.

---previous discussion---
A broad longwave trough over the central US will become more
amplified later this week with the arrival a strong, digging
shortwave. Another shortwave tracks across B.C. into the northern
Rockies by this weekend. The biggest differences in the model lie
with the magnitude of the vorticity maxima as it rounds the base
of the trough. The 12z CMC is considerably stronger and flatter
compared to the rest of the guidance. The 00z GFS / 12z ECMWF are
in very good agreement and while the NAM is also agreeable, its
associated surface low tracking through the lower Ohio Valley into
the Great Lakes region is stronger compared to the ensemble
spread.

Beyond mass fields, QPF is most different across the southern
Plains and Texas Gulf Coast where a stalled frontal boundary sits
for a couple of days. The GFS is wetter compared to the
ECMWF/CMC/UKMET for Friday, but also is more progressive than the
ECMWF/CMC, which holds the front inland the longest. The
faster/further south solution seems more plausible given the
limited instability in place and the approach of the Canadian high
pressure rapidly dropping south.

Overall, the preference is for a 00z GFS, 12z ECMWF/UKMET blend
across the CONUS.


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

Taylor