Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
242 PM EDT Mon May 07 2018

Valid May 07/1200 UTC thru May 11/0000 UTC

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

12Z model preferences with confidence intervals
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
GFS/NAM initialization errors are minimal and do not appear to
degrade their short range forecasts.


Upper level trough moving into the Pacific Northwest Tue-Thu
Lee cyclogenesis over the High Plains Wednesday-Thursday
Trough weakening while departing the East Tue-Wed
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: Non-ECMWF blend; confidence slightly above ave

The 12z ECMWF has trended weaker with the system moving across the
Northwest, despite a building upstream ridge and a closed northern
stream high to its north and northwest, which would argue for a
system which is stronger or more closed aloft.  Prefer a
compromise of the 12z GFS, 12z NAM, 12z UKMET, and 12z Canadian
with slightly above average confidence.


Shortwave ejecting through the Northern Rockies today,
then Northern Plains Tuesday and Upper Midwest Wednesday
Low consolidating over the Midwest tracking through Great Lakes
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: Non-NAM blend; Confidence slightly above ave

Timing differences with this system have fallen within the noise
level.  The 12z NAM is the strongest/most northerly with the low
crossing MI, which does force its precipitation forecast to stray
from the other guidance.  A compromise of the 12z GFS, 12z UKMET,
12z Canadian, and 12z 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