Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1122 AM EST Wed Jan 16 2019

Valid Jan 16/1200 UTC thru Jan 20/0000 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 through 18/12Z, 00Z
ECMWF/UKMET/06Z FV3 blend after 18/12Z
Confidence: Slightly above average

Model solutions show very minor differences during the initial 48
hours of the forecast, and a general model blend should resolve
all significant systems/features well. After 12Z on Fri,
differences begin to emerge with an amplifying shortwave moving
from the Rockies into the southern/central Plains. The GFS becomes
faster than the overall consensus (and faster than the 06Z GEFS
mean), while the NAM is on the slower side of the spread. At this
time, the best-clustered solutions with an ensemble mean-based
consensus in terms of the timing of this system are the 00Z
ECMWF/UKMET. Additionally, the ECMWF been the most stable solution
in terms of the timing of this system over the past few model
runs. The 06Z FV3 also showed timing similar to this preference.
Additional differences emerged with an upper-level low forecast to
reach western Canada Fri/Fri night, with the GFS much farther
south with this feature relative to almost all other guidance
(including the 06Z GEFS mean), the 00Z ECMWF/UKMET and 06Z FV3
were also well clustered with the ensemble means here. These three
solutions are the preference after 12Z on Fri.


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

Ryan