Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
130 PM EDT Mon Apr 22 2019

Valid Apr 22/1200 UTC thru Apr 26/0000 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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...Shortwave crossing the Northeast on Wednesday...
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Preference: 12Z NAM/00Z UKMET blend
Confidence: Slightly above average

Ensemble trends and clustering support a middle ground approach
best led by the 12Z NAM and 00Z UKMET. The 12Z GFS was a strong
outlier and was faster with the surface low/cold front moving
through the northern tier. The 00Z ECMWF on the other hand was a
bit weaker and farther south than the remaining model consensus.


...Remainder of the CONUS...
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Preference: General model blend, lean by 12Z GFS/00Z ECMWF
Confidence: Slightly above average

Differences across the rest of the nation (outside of the Great
lakes/Northeast) were relatively minor and more tied to mesoscale
interactions than mass field differences. Across the Southern
Plains, the 12Z NAM/GFS and 00Z ECMWF/UKMET/CMC showed similar
timing, consistent with the 00Z ECMWF mean which has not wavered
much in strength/timing over its past few cycles. Across the
Northwest, differences with shortwaves embedded within a zonal
flow pointed into Washington/Oregon were not significant enough to
rule out any one solution.


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

Otto