Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1206 PM EDT Fri Jul 13 2018

Valid Jul 13/1200 UTC thru Jul 17/0000 UTC

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

12Z Model evaluation including preference and forecast confidence
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

...Overall Model Analysis for the CONUS...

Overall Preference: General model blend
General Confidence: Slightly above average

The weak flow pattern persists across the CONUS over the next few
days, with 500mb heights generally varying by less than 60m across
the country, though a deeper amplification of the closed low into
the upper Midwest and Great Lakes drops another frontal zone Mon
into Tues.  There is model variation with the inner core of the
upper low and the surface low/occlusion/triple point in Canada
with the UKMET/12z NAM outpacing the GFS with the ECMWF and CMC
lagging a bit...but the timing of the frontal zone in the CONUS is
solid.

There is also some timing/strength variation with the weak
shortwave emerging through a weakness in the Pacific ridge
offshore OR/WA by Sun/Mon.  Typical timing differences with
GFS/NAM and UKMET outpacing the ECMWF/CMC and the UKMET being a
bit more amplified than the other guidance...but sensible weather
impacts are small with exception of the 12z NAM/GFS drawing a bit
more moisture northward for some increased QPF in terrain in
OR/ID/NV/N CA by Mon...but this is minor to the mass field
difference.  As such a general model blend can be supported
hedging toward most central 12z GFS/00z ECMWF solutions with
respect to weighting in the blend. 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