Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
235 AM EDT Wed Jun 20 2018

Valid Jun 20/0000 UTC thru Jun 23/1200 UTC

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

00Z model evaluation...including preferences and confidence 
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...Upper trough/closed low over the West...
...Dropping down across the Mid MS/OH Valleys by Friday/Saturday...
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Preference: Non-NAM blend
Confidence: Above average

The 00Z NAM is perhaps a tad too deep very early in the period on
day 1 as the height falls eject out across the central Plains.
Thereafter, as the energy ejects across the middle MS and OH
Valleys, the 00Z NAM tends to bring height falls a little south of
the global models. The global models are well clustered, so a
non-NAM blend will be preferred.


...Series of upper troughs crossing the Northwest through Friday...
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Preference: Blend of the 00Z GFS and 00Z ECMWF
Confidence: Slightly above average

The 00Z NAM is overall a little too deep it appears with a pair of
troughs that are forecast to cross the Northwest through Friday.
On Saturday, the lead trough ejects out across the central Plains
with the NAM being the strongest solution. The 00Z UKMET trended a
little slower with both systems and is close to the model
consensus. The 00Z CMC gradually becomes a little weak with the
lead system as it arrives across the central Plains and looks a
little too slow along with the NAM with the second system. Better
model clustering and ensemble support lies with the 00Z GFS and
00Z ECMWF, so a blend of these solutions will be preferred.


...Large scale troughing over the Northeast this period...
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Preference: General model blend
Confidence: Above average

The models are in good agreement with this system.


...Mid level low center/surface trough over Texas...
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Preference: General model blend
Confidence: Above average

The guidance has come into considerably better agreement with this
feature which is expected to drop gradually southwest down into
Mexico over the next couple of days, although there will be some
vort energy from the mid level closed low that breaks away and
lifts northeast up across eastern TX and the lower MS Valley while
gradually shearing out. A general model blend will be preferred.


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

Orrison