Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
223 AM EDT Tue Aug 07 2018

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

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

00Z Model Evaluation Including Preferences and Forecast Confidence
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...Overall Synoptic Pattern across the CONUS...
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Preference: General model blend
  Exclusions:  Remove 00z GFS in the Great Lakes/Northeast
Wed-Thurs
Confidence: Slightly above average

07z update: The 00z CMC has trended faster with the Pacific
offshore trof in line with the other guidance, and while there is
some slowness/deeper amplification across Quebec by the end of day
3, there is much better timing with the mid-stream wave crossing
the Great Lakes/Northeast...enough for inclusion of the CMC in the
CONUS.  This leaves a general model blend with exception of the
00z GFS across the Great Lakes/Northeast Wed into Thurs.


---Prior Discussion---
The overall trends have been toward slowing the eastward progress
of the shortwave crossing out the Central Plains currently and
tracking through the Great Lakes Wed into the Northeast by Thurs,
mainly focused on slightly more amplified ECMWF and ECENS member
solutions, as well as the UKMET, CMC.  The 00z NAM trended a bit
slower, while the 00z GFS keeps continuity but remains weak and
fast, in line with its bias.  The 12z CMC is may not be as
amplified as prior runs, but shows reduced interaction/phasing
with the sharp James Bay trof, indicated by the remaining
solutions/ensemble.  This leads it to be further south and east
than the ECMWF/UKMET, making it less favorable.  

Elsewhere, the ensembles show an oscillating trend from 12z to 00z
cycles with respect to the depth/compact nature of the closed low
in the northeast Pacific.  The 12z cycle was not much off, showing
more open solution, represented by the GFS/NAM and ECMWF.   The
12z CMC is the most compact, but also stands out being slow having
little forcing to kick into coastward by the end of the forecast
period.  This would support a Non-CMC blend for the west coast.

The secondary cold front crossing into the Great Lakes toward the
end of the forecast period, shows remarkable timing agreement with
similar spot lows and generally similar placement of QPF.  As such
a general model blend is supported for this front.

All together, a blend of the 12z ECMWF/UKMET and 00z NAM seem best
as a whole, with exclusion of the CMC throughout the main features
and removal of the fast GFS through the Great Lakes/Northeast
Wed-Thurs.  Confidence is slightly above average


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

Gallina