Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1241 PM EDT Fri Apr 19 2019

Valid Apr 19/1200 UTC thru Apr 23/0000 UTC

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

12Z Model Evaluation...with Preferences and Confidence
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...Overall Pattern Across the CONUS...
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Preference: General model blend
Confidence: Slightly above average

The synoptic pattern over the next 3 days focuses on two distinct
systems, one being a closed low affecting the eastern U.S. while
another shortwave trough moves into the Pacific Northwest then it
drops into the Four Corners region. Overall, a general model blend
is preferred with the most inclusion weighted toward the GFS/ECMWF
and its ensemble means.

For the eastern U.S. closed low system, there is really good model
agreement through about 60-72 hours as the closed low lifts into
the Northeast. The only exception is the UKMET, which advertises
the system to open back up, and is not seen in any of the other
models and thus is considered an outlier for this cycle. The
similar mass fields yield fairly good agreement in the QPF
distribution and so a general model blend with the heaviest weight
on the GFS/ECMWF is preferred at this time.

For the Western U.S. shortwave trough, more weight was given to
the ECMWF/GFS/NAM though a general model blend is also preferred
for this system as it pushes onshore into the Pacific Northwest.
As it drops into the Four Corners region, the NAM digs a bit too
much and the ECMWF appears to be a bit too slow, but overall the
model agreement is above average through 84 hours.


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

Taylor