Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
243 AM EDT Thu May 16 2019

Valid May 16/0000 UTC thru May 19/1200 UTC

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

00Z NAM/GFS Evaluation with Preliminary Preferences and Forecast
Confidence
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...Overall Pattern across the CONUS...
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Preference: 00Z NAM, 00Z GFS, 00Z ECMWF blend
Confidence: Average

...07Z update...

Changes in the 00Z ECMWF/UKMET/CMC were directed toward a the
previous preference for the most part with most of the systems
impacting the lower 48. There was continued good agreement for
staying away from the faster 00Z GFS near New England Friday night
and with the Central Plains surface low Saturday morning to Sunday
morning. Elsewhere, the GFS still appears to be worthwhile when
used as part of a blend with the 00Z NAM and 00Z ECMWF (with the
00Z ECMWF only making minor changes from its 12Z cycle).

...previous discussion follows...

A trough-ridge-trough pattern across the CONUS at the start of the
short range transitions to the western trough reaching the Plains
while the ridge moves over the East Coast. By Sunday morning,
another large trough will be near the West Coast. At the surface,
a cold front and low will track through the Great Lakes and
Northeast, with the 00Z GFS outpacing the remaining model
consensus by Friday evening near New England. The 00Z NAM/12Z
ECMWF show better agreement here. Across the Central Plains, the
00Z NAM, 00Z GFS and 12Z ECMWF show the best agreement with the
ensemble means at 500 mb through Sunday morning but the GFS
appears to be a bit of a stronger outlier at 500 mb with also a
strong and westward displaced 850 mb low across Nebraska and South
Dakota. The 00Z NAM and 12Z ECMWF appears to match better to the
remaining model consensus including some recent trends to be
faster in the Great Plains for Saturday into Sunday. Across the
West for Sunday, despite some minor timing differences, there is
generally good agreement with a general model blend sufficing. The
only other place of note is off of the Florida peninsula where the
00Z NAM is a stronger outlier with an upper low tracking toward
the Bahamas and is not preferred.

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

Otto