Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
247 PM EDT Sat Jun 30 2018

Valid Jun 30/1200 UTC thru Jul 04/0000 UTC

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

12Z model evaluation...including final preferences
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...Mean upper trough advancing from Montana/Wyoming to the Great
Lakes/accompanying cold front...
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Preference: non 12Z NAM blend
Confidence: Average

Differences are greatest early in the forecast with the 12Z NAM's
effective cold front quicker through Sunday evening but the models
get into better alignment as the surface front returns north as a
warm front across the Mississippi Valley into Tuesday. The 12Z
UKMET/CMC adjusted toward the 12Z NAM/GFS and 00Z/12Z ECMWF
placement with a surface low forecast to track through the upper
Mississippi valley on Sunday, leaving the 12Z NAM as the outlier.


...Westward moving mid/upper low/trough along the eastern/central
Gulf Coast...
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Preference: General model blend
Confidence: Average

The models show similarly with this system. No significant changes
were noted between the 12Z and 00Z runs of the ECMWF/UKMET/CMC.


...Pronounced upper low/trough taking shape over the Pacific
Northwest by early next week...
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Preference: non 12Z NAM blend
Confidence: Slightly above average

The 12Z NAM remains fastest with the upper trough, related cold
front and surface low reaching South Dakota Tuesday morning. The
remaining 12Z deterministic guidance shows good agreement with a
slower track than the nam and in line with the latest ensemble
means.


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

Otto