Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1126 PM EST Thu Jan 03 2019

Valid Jan 04/0000 UTC thru Jan 07/1200 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: General model blend
Confidence: Slightly above average

A closed mid/upper low currently over the Arklatex region will
track across the southeast US then northeast into the Mid-Atlantic
and off the Northeast US coast while a northern stream shortwave
moving through the Great Lakes will be the main driver to help
push it off the coast by 06.00z. There is very good model
agreement in the mid/upper level mass fields across the eastern US
such that a general model blend of the available guidance would
suffice. At the surface, a low pressure will lift through the TN
and OH Valleys then off the coast of the Mid-Atlantic. Once that
system passes, general ridging will encompass much of the eastern
US while longwave troughing develops across the western/central
US.

For the Western US, the next weather system to impact the region
will be Saturday as a longwave trough approaches the west coast. A
compact surface low is expected to push onshore the northern
California or southern Oregon coast and bring widespread moderate
to locally heavy precipitation. Compared to the past 12-24 hours,
there is slightly better model agreement with the speed and
location of the surface low as it pushes onshore Saturday. The GFS
continues to be somewhat faster compared to the rest of the
models, but its difference is not as large as it was before. By
the end of the forecast period (07.00z), another shortwave is
likely to move into parts of the Pacific Northwest. The GFS is
more amplified compared to the ECMWF with this feature as it moves
into Washington State. For now, a general model blend is preferred
for the CONUS this cycle. 

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

Taylor