Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
106 AM EDT Sat Jun 02 2018

Valid Jun 02/0000 UTC thru Jun 05/1200 UTC

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

00Z NAM/GFS evaluation along with preliminary preferences
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

...Slow moving upper trough over the Mid-Atlantic region today...
...Coastal low off of the northern Mid-Atlantic coast through
Monday morning...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: non 12Z UKMET blend
Confidence: Average

The biggest differences here are with the surface low forecast to
strengthen off of the northern Mid-Atlantic coast on Sunday and
track northeastward. While ensemble scatter low plot spread is
large and the 12Z UKMET is not an outlier...the non 12Z UKMET
models show decent agreement so a non 12Z UKMET blend will be
preferred for this system.

...Negatively titled upper trough crossing the upper MS Valley
Saturday night and Great Lakes on Sunday...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: non 12Z UKMET blend
Confidence: Average

While the 12Z UKMET is not an outlier with respect the ensemble
guidance, it is alone relative to the remaining deterministic
models regarding its stronger depiction of the negatively tilted
trough axis across the Great Lakes and Northeast on Sunday into
Monday. Ensemble spread is larger than average regarding 500 mb
heights and a surface low over the Great Lakes into Ontario, but
will go with the deterministic consensus at this time, led by a
non 12Z UKMET blend.


...Mid-level vorticity maximum entering the Southwest U.S. on
Saturday...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: General model blend
Confidence: Slightly above average

The models show similarly with this system, with minor detail
differences best resolved with a general model blend.


...Upper trough reaching the Pacific Northwest Sunday/Monday...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: General model blend
Confidence: Above average

The models show minor differences with this system. Given the
relatively small spread and decent run to run consistency, a
general model blend is preferred to smooth out these smaller scale
differences.


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

Otto