Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1225 PM EDT Sun Apr 14 2019

Valid Apr 14/1200 UTC thru Apr 18/0000 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, weighted to 12Z GFS and
            00Z ECMWF after 17.00Z (Day 3)
Confidence: Above average

Models are in excellent agreement through the first 48-60 hours of
the forecast. For example, by Monday Night (16.06Z), all the
deterministic models and ensemble means place the surface low
positions over the Canadian Maritimes and Central Plains within
about 80 miles of each other. Ensemble spread with the mass fields
is very limited, and thus a general model blend is preferred.
Forecast confidence is above average.

By Tuesday Night and Wednesday, some greater differences begin to
emerge with a trough pushing into the Plains. The 12Z GFS and 00Z
ECMWF are in very good agreement with the trough position and
structure, and the position of the surface lows in the Plains. The
preference is to shift the blend toward a more significant
weighting of those two models by Day 3, given strong support from
ECMWF ensemble members. The 00Z CMC/UKMET and 12Z NAM lag the
trough more. While this can't be ruled out, it is perhaps a less
likely scenario at this point, given the ensemble member
distribution.


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

Lamers