Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1120 AM EST Tue Jan 29 2019

Valid Jan 29/1200 UTC thru Feb 02/0000 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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...Overall Pattern across the CONUS...
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Preference: General model blend
 Exception: 12z GFS/00z ECMWF blend after 01/00z
            West Coast
Confidence: Above average

Both the 12z NAM and 12z GFS are close to the consensus/ensemble
means with respect to the large scale features across most of
CONUS through Day 3. There are some small scale differences
concerning the timing Arctic boundaries over the East, especially
from Day 1 into early Day 2. Otherwise, there is excellent model
agreement with the surface wave that forms on the front and
crosses northern New England during the second half of Day 1.

The 12z NAM remains slower than the consensus with the developing
positively tilted long wave trough approaching the West Coast,
particularly after 01/00z. In contrast, the 12z GFS has sped up
its solution (when compared with the 06z run) with the long wave
trough, and is now in much better agreement with the 00z ECMWF/00z
ECMWF ensemble mean/06z GEFS mean. Both the 00z UKMET/CMC remain
slower than the 12z GFS/00z ECMWF consensus (with the 00z UKMET
much slower), and were not included in the preference.

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

Hayes