Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
253 PM EDT Tue May 14 2019

Valid May 14/1200 UTC thru May 18/0000 UTC

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

12Z Final Model Evaluation with Preferences and Confidence
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Overall Pattern across the Continental U.S.
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Preference: 12Z GFS/12Z NAM/00Z EC mean blend
Confidence: Average

An amplified upper level flow pattern is expected across the
nation through the remainder of this week.  An anomalous upper
level low initially over the Northeast U.S. is forecast to slowly
lift towards the northeast to the Canadian maritimes by Thursday,
and a rather pronounced trough with developing closed low aloft
develops across the West Coast region by Wednesday night and
persisting through Friday morning.  Meanwhile, a broad upper level
ridge will govern the weather pattern across the central U.S. and
gradually expand towards the eastern U.S. by the end of the week.

The biggest differences regarding mass fields at this time
involves the 00Z and 12Z UKMET depictions of a stronger ridge over
the Gulf Coast region that also extends northward across the
central plains.  The UKMET continues to indicate a slightly slower
and more amplified trough axis progression over California on
Thursday.  The CMC becomes weaker and more progressive with a
shortwave tracking across the northeast U.S. on Thursday prior to
the upper level ridge building in.  Farther to the north across
central Canada, the ECMWF is showing two closed lows (other
guidance supports one main low) near Hudson Bay on Thursday, and
then becomes displaced from the model consensus by Friday with the
main upper low from the ECMWF well to the southeast of the model
consensus.  Most of the differences associated with this are north
of the Canadian border, but does result in lower 500mb heights
over the northern Great Lakes region.  Taking these factors into
consideration, the model preference for the synoptic scale pattern
is a blend of the 12Z GFS/NAM/00Z EC mean.


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

Hamrick