Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
300 AM EDT Fri Jun 01 2018

Valid Jun 01/0000 UTC thru Jun 04/1200 UTC

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

00Z model evaluation...with final preferences
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

...Upper trough crossing the Great Lakes/Ohio Valley today and
Mid-Atlantic Sat/possibly off the coast Sun...
...Coastal low off of the northern Mid-Atlantic coast through
Monday morning...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: Blend of 00Z GFS/ECMWF/CMC
Confidence: Average

Some latitude differences exist with the placement of a surface
low off of the Mid-Atlantic coast. Trends in the ensemble scatter
low plots support a middle ground best represented by a 00Z
GFS/ECMWF/CMC blend with the 00Z NAM on the far southern edge of
the ensemble spread and 00Z UKMET on the northern side of the
available ensemble members.


...Upper trough crossing the northern Rockies this
morning...northern Plains tonight, and upper MS Valley Sat night...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: Blend of 00Z GFS/UKMET/CMC
Confidence: Slightly below average

The models show varying degrees of evolution with the southern end
of a negatively tilted trough axis crossing the upper MS valley
Saturday night. The 00Z NAM is perhaps the weakest with the
strength of energy in the base of the trough axis and a bit faster
than the consensus, but its placement matches well to the GEFS and
ECMWF means through much of the short range period.

However, the 00Z GFS is the strongest of the 00Z models while the
00Z ECMWF trended weaker with the energy in the base of the
negatively tilted trough axis as it reaches the lower Great Lakes.
A blend of the 00Z GFS/UKMET/CMC matches best to the agreeable
ensemble means with trough evolution. Confidence is a bit below
average given the poor model agreement and run to run consistency.


...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. The 00Z
ECMWF/UKMET/CMC showed little change from their previous cycles
for this system.


...Upper trough impacting the Pacific Northwest Sunday/Monday...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: General model blend
Confidence: Average

The models show minor differences with this system given the 60-84
hour forecast range of this system. Given the relatively small
spread, a general model blend is preferred to smooth out these
smaller scale differences. The 00Z ECMWF/UKMET/CMC showed little
change from their previous cycles for this system.


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

Otto