Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1137 PM EST Tue Jan 15 2019

Valid Jan 16/0000 UTC thru Jan 19/1200 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: Blend of 12Z ECMWF, ECMWF ENS, CMC
Confidence: Slightly above average

Models are in excellent agreement overall through the first 48
hours of the forecast (17.12Z), after which point some differences
begin to emerge with a strong trough that will kick through the
West and emerge into the Plains on Friday Night. In general, there
seems to be division into two primary scenarios. The 00Z GFS, NAM
and 12Z UKMET represent a scenario where the associated vorticity
max digs a little further south, and the trough lags slightly
more, leading to eventual phasing issues with the northern stream
broad trough over the Great Lakes. Meanwhile, the 12Z ECMWF and
CMC show a cleaner phasing, and are supported by nearly all of the
ECMWF and CMC ensemble members. The preference leans toward the
ECMWF and CMC given greater ensemble support, consistency with
previous forecasts, and consistency with the medium range blends.
There also don't appear to be strong mechanisms in place that
would tend to lead to maintenance of split flow and poor phasing.
Prior to Friday, though, a broad-based model blend could be
utilized across the CONUS with above average confidence.


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

Lamers