Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1249 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 NAM/GFS Evaluation with Preliminary Preferences and Confidence
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Overall Pattern across the Continental U.S.
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Preference: 12Z GFS/00Z ECMWF 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 UKMET depiction of a slightly stronger ridge over
the Gulf Coast region, and this also holds true for the 00Z CMC to
a lesser degree.  The UKMET also indicates a slightly slower
trough axis progression over California on Thursday.  Farther to
the north across central Canada, the ECMWF, EC mean, and the CMC
are showing two closed lows near Hudson Bay on Thursday, whereas
the NAM and GFS have one main closed low.  The initial preference
at this time will be a blend of the ECMWF/GFS/NAM.


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

Hamrick