Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
235 AM EDT Wed Apr 11 2018

Valid Apr 11/0000 UTC thru Apr 14/1200 UTC

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

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


System digging/moving from the West into the Plains
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: NAM/UKMET blend; confidence slightly above ave

There is some east-west spread with the surface low in the
Plains/Midwest Saturday morning with the 00z ECMWF on the east
side of the spread and the 00z GFS on the west side due to
differences in the leading edge of the mid-level height
gradients/eastern extent of the core of the upper trough.  Similar
spread exists in their respective ensemble mean solutions, which
somewhat lower confidence in the model choice.  A blend of the
current guidance, similar to a 00z NAM/00z UKMET mass field blend,
which resolve the minimal issues with slightly above average
confidence.


Shortwave moving through the Southeast early Wednesday
Shortwave moving through the Northeast Wednesday night
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The guidance shows good agreement with these systems.  A
compromise of the 00z GFS, 00z NAM, 00z Canadian, 00z ECMWF, and
00z UKMET is preferred with above average confidence.


Great Lakes-New England Shortwave/Low Thursday/Friday
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: UKMET/ECMWF blend; confidence slightly above average

The 00z GFS is a bit weaker than the other guidance with the
parent shortwave, allowing the mid-level ridging to its south to
be stronger which leads to a more northerly surface solution than
the other guidance and lies on the northern side of the 12z global
ensemble guidance.  However, the 00z UKMET/00z ECMWF trended
slightly in this direction.  A compromise of the 00z UKMET/00z
ECMWF 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