Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1057 AM EST Wed Jan 23 2019

Valid Jan 23/1200 UTC thru Jan 27/0000 UTC

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

12Z Model Evaluation Including Preferences and Forecast Confidence
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...Pattern across the CONUS...
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Preference: Blend of the GFS/ECMWF/NAM
Confidence: Slightly Above Average

In the wake of the storm system currently tracking through the
central/eastern US, the synoptic pattern across the CONUS will
feature broad longwave troughing centered on the northern Plains
and Upper Midwest. There is above normal confidence and good
agreement with the latest model guidance in the first 48 hours
across the CONUS with respect to the mass fields.

A few shortwave troughs will slip over a ridge off the western US
coast during the forecast period, the first being Thursday night
into Friday. There are some temporal differences noted in the
latest guidance, with the biggest differences seen in the CMC,
which seems like an outlier. Otherwise, there is fairly good
agreement as the wave enters the Pacific Northwest. As the system
drops quickly south towards southern California, the favorable
model agreement maintains though with the expected increase in
variability by the end of the forecast period.

Within the broad cyclonic flow across the central US, a few
shortwaves will quickly track through the flow, bringing light
precipitation. Model timing/placement is average at best. The
first system will quickly track through Thursday night into Friday
across the northern Plains, reaching the lower Ohio Valley by
Friday night. The main model differences seem to be the slower NAM
solution and again the spatial problems seen in the CMC.

As such, for this cycle, the WPC preference is for a general blend
of the GFS/ECMWF/NAM with some inclusion of the UKMET. The CMC
exhibited the greatest deviation from the model consensus and
therefore was not included.


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

Taylor