Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
232 AM EDT Mon May 14 2018

Valid May 14/0000 UTC thru May 17/1200 UTC

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

00Z model preferences with confidence intervals
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NAM/GFS initialization errors do not seem to degrade their short
range forecasts.


Merging upper systems across the West/northern Rockies
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: Non-NAM blend; confidence above average

While the guidance looks similar aloft, the 00z NAM is more
eastward with a low at the leading edge of the initial Great Basin
system when compared to the other deterministic and ensemble mean
guidance.  A compromise of the 00z Canadian, 00z UKMET, 00z ECMWF,
and 00z GFS is preferred with above average confidence.


Surface low streaking north of US/Canadian border Tue/Wed
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: Non-UKMET blend; Confidence slightly above average

The 00z UKMET was the quickest with this system.  A compromise of
the 00z GFS, 00z NAM, 00z ECMWF, and 00z Canadian consensus is
preferred with slightly above average confidence.


Possibly convective deep layer cyclone
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: GFS/ECMWF/UKMET blend; confidence slightly above
average

The 00z NAM/00z Canadian were the quickest of the guidance.  The
remainder of the guidance is reasonably close.  A compromise of
the 00z GFS, 00z ECMWF, and 00z UKMET is preferred with slightly
above average confidence.


Base of the eastern Canada upper low/trough
Stationary front in the northern Mid-Atlantic states Wed
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: GFS/UKMET/Canadian blend; confidence slightly above
average

There remains some latitude spread with the front settling into
the Mid-Atlantic States with the 00z NAM in two days and the 00z
ECMWF somewhat more northerly with this boundary.  Since the
guidance is still advertising a 1022-1024 hPa surface high to move
through southern Quebec and Atlantic Canada, a placement closer to
D.C. is preferred here.  A compromise of the 00z GFS, 00z
Canadian, and 00z UKMET is preferred with slightly above average
confidence. 


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

Roth