Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1139 AM EST Thu Jan 16 2020
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 Forecast Confidence
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...Central to Eastern US system...
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Preference: Non-NAM, non-CMC blend after 18.12z
Confidence: Slightly above average
Shortwave trough moving into the western U.S. tonight will cross
into the Central Plains this weekend. Through 48 hours, the spread
seen in the deterministic guidance has lessened with overall above
average agreement at 500 mb. The NAM is a tad more amplified with
its trough axis as the wave takes on a negative tilt. At the
surface, there is still some latitudinal spread with the ECMWF and
ECENS members showing a northern/northwest favor compared to the
CMCE members further south/southeast. The GFS/GEFS members lie in
the middle and probably provide a good approach for beyond 48
hours. The 00Z UKMET is also a good proxy. So, with the NAM being
a bit amplified and the CMC too far south/southeast, will lean on
a non-CMC, non-NAM blend.
...Pacific Northwest...
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Preference: General model blend
Confidence: Slightly above average
The next system poised to affect the Pacific Northwest comes later
this weekend as an area of low pressure approaches western Canada.
A plume of higher moisture pushes onshore Oregon/Washington.
Overall, differences at 500 mb are fairly minor with some of the
typical biases seen where the GFS is a touch faster and the CMC is
on the slower side of the model spread. At the surface, there is
some higher spread and model variability but the majority of the
impactful weather pushing into the Pac NW has fairly similar
solutions so will continue to suggest a general model blend for
this area.
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml
Taylor