Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1213 PM EDT Fri Aug 17 2018

Valid Aug 17/1200 UTC thru Aug 21/0000 UTC

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

12Z Model Evaluation...with Preferences and Confidence
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

...Overall Synoptic Pattern across the CONUS...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: Blend of 12Z GFS, 00Z CMC and 00Z ECMWF
Confidence: Average

Over the next few days, the 12Z GFS, 00Z CMC and 00Z ECMWF offer
decent agreement and all three deterministic models are contained
well within the ensemble spread envelope for their various mass
fields. One notable exception regards the upper trough and
associated surface low near southern New England by Monday, as the
ECMWF and CMC are more amplified than the GFS. Based on the recent
pattern of deeper troughs and closed lows that have evolved over
the CONUS over the last week, the thinking is that the ECMWF and
CMC are a more likely solution to verify here versus the flatter
GFS.

The 12Z NAM again shows a notably faster progression and digging
with the trough pushing into the West Coast on Sunday, and is out
of phase with the Northeast trough as compared to the other
models. The 12Z UKMET appears generally fine in the Northwest, but
appears too deep with the central Plains/Midwest trough by Monday,
and a bit too flat with the Northeast U.S. trough. Thus again, a
preference overall toward the better clustering of the GFS, CMC
and ECMWF for 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

Orrison