Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1256 AM EDT Sun Jul 01 2018

Valid Jul 01/0000 UTC thru Jul 04/1200 UTC

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

00Z NAM/GFS model evaluation...including preferences/confidence
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...Mean upper trough advancing from the Nebraska panhandle to the
Great Lakes/accompanying cold front...
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Preference: Non-00Z NAM model blend
Confidence: Above average

Models are in agreement early on before the 00Z NAM becomes a bit
quick with the surface cold front by Sunday evening. Will favor a
non-00Z NAM model blend.


...Westward moving upper circulation along the eastern/central
Gulf Coast...
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Preference: Blend of the 00Z GFS/12Z ECMWF
Confidence: Slightly above average

A well advertised upper low should continue pushing across the
Gulf Coast the next few days with a position near the
Texas/Louisiana border by 04/1200Z. Very few ensemble members show
a low stamp with this system although a cyclonic circulation is
evident in forecast wind barbs. At times the 12Z CMC/UKMET become
slow before joining the rest of the camp by mid-week. Will favor a
combination of the 00Z GFS/12Z ECMWF given their consistency with
ensemble means and are more reflective of the heavy rainfall
potential.


...Pronounced upper low/trough taking shape over the Pacific
Northwest by early next week...
...Secondary upper low inhabiting the east Pacific by Tuesday...
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Preference: Lead upper low: Blend of the 00Z GFS with the 12Z
ECMWF/UKMET, Secondary low: Blend of the 00Z GFS/12Z ECMWF
Confidence: Average

Lowering heights will descend upon the Pacific Northwest by Monday
evening before sliding eastward while another upper low reaches
the offshore waters the following day. Regarding the first system,
the 00Z NAM is displaced east of the consensus. Eventually the 12Z
CMC becomes out of phase with the better clustered solutions so
will lean toward a 00Z GFS and 12Z ECMWF/UKMET combination.
Regarding the system to the west, the 12Z UKMET is a bit quicker
based on 570-dm ensemble spaghetti plots so will stay closer to
the 00Z GFS/12Z ECMWF.


...Upper low approaching the southeastern U.S. coast by mid-week...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: Blend of the 00Z GFS/12Z ECMWF
Confidence: Average

An upper low descending southwestward from Bermuda will eventually
near the Georgia/Florida coast by late Tuesday/early Wednesday.
588-dm ensemble spaghetti plots show decent consistency among the
12Z GEFS/ECMWF ensemble members with their operational
counterparts following suit. One true outlier is the 12Z UKMET
which sits in the northeastern Gulf of Mexico. The preference is a
blend of the 00Z GFS/12Z ECMWF.



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

Rubin-Oster