Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1228 AM EDT Wed Mar 27 2019

Valid Mar 27/0000 UTC thru Mar 30/1200 UTC

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

00Z Model Evaluation With Preferences and Confidence
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...Overall Pattern Across the CONUS...
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Preference: General model blend
            Greatest weight to 12Z ECMWF; least weight to 00z GFS
Confidence: Slightly above average

Models are in very good agreement through most of the forecast
period across the CONUS. As a trough over the western US moves
into the central Plains, it will begin to interact somewhat with a
northern stream shortwave trough moving across southern Canada.
The degree of which these systems phase or not is the biggest
model difference through the next 84 hours.

The 00z GFS continued its 12z run solution, which shows less
phasing of the two features, with the southern stream kicking out
ahead of the northern stream just enough to limit much phasing.
This is different from the other operational models which all show
more phasing. The 00z NAM and 12z CMC are the most phased, with a
deeper surface low tracking across the mid-MS and Upper Midwest
Friday-Saturday. The differences in these mass fields do result in
a variety of QPF solutions, both spatially and in magnitude.

There has been better consistency in the ECMWF forecasts the past
few model cycles and this agrees more with the ensemble spread as
well. For now, will lean on a more phased solution but perhaps not
to the degree that the CMC and NAM are advertising. A general
model blend then would suffice, which should blend out the less
phased GFS and amplified CMC. A solution near the 12z ECMWF is
preferred.


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

Taylor