Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
307 PM EDT Wed Mar 27 2019

Valid Mar 27/1200 UTC thru Mar 31/0000 UTC

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

12Z Model Evaluation With Preferences and Confidence
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

...Overall Pattern Across the CONUS...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: 12Z GFS/ECMWF/UKMET blend
Confidence: Slightly above average

Models are in good general agreement with the decay of the closed
low off the West Coast and the interaction of southern stream
energy from that low with a trough approaching the north-central
CONUS from Canada Friday into Saturday. The degree of which these
systems interact over the central CONUS and the strength of the
southern stream energy are the biggest model differences through
84 hours.

The 12Z GFS has slowed the southern stream wave which results in
more separation with the northern stream trough on Saturday and
features a similar solution to the 12Z ECMWF. The 12Z UKMET is now
very similar to the 12Z GFS with the southern stream and is much
less phased by late Saturday than the 00Z run. The strength of the
southern stream trough is strongest in the 12Z NAM which results
in higher magnitude QPF compared to the preferred GFS/ECMWF/UKMET
solutions. However, the 12Z ECMWF now features a stronger southern
stream, so the NAM is less of an outlier for magnitude, but it is
still faster than the preferred blend.


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

Jackson