Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
109 AM EDT Sat Jul 07 2018

Valid Jul 07/0000 UTC thru Jul 10/1200 UTC

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

00Z NAM/GFS evaluation...with preliminary preferences/confidence
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

...Overall Model Analysis for the CONUS...

Overall Preference: 00Z GFS, 12Z ECMWF, 12Z UKMET blend
General Confidence: Slightly Above Average

A large ridge will dominate over the center of the country with
the passage of a longwave trough axis across the top and into the
Great Lakes/Northeast by Tuesday morning. An accompanying cold
front will impact the northern tier of the U.S. into early next
week with the better model agreement seen in the 00Z GFS, 12Z
ECMWF and 12Z UKMET for mass fields. The 00Z NAM is a bit more
aggressive with height falls across Ontario which results in a
farther south position of the cold front into the Midwest/Plains
on Monday compared to the remaining consensus.

Across the Northwest by Monday, an upper trough begins to near the
coastline, with good agreement seen except for the 12Z CMC which
was displaced farther offshore given differences in its ridge
position across the western CONUS.


...Tropical Depression Three off the East Coast...

Preference: 00Z GFS/12Z NAM blend nearest to 03Z NHC advisory
Confidence: See NHC products

While no model is in total agreement with the 03Z NHC advisory, a
general blend between the 00Z GFS and 12Z NAM is closest in
position and strength through Monday morning, but even this blend
is closer to the coast than the NHC advisory. The 00Z NAM is also
stronger than the GFS, with the NHC forecasting a 50-65 kt
tropical cyclone by 12Z/10, with the NAM showing over 70 kt at
this time. The 12Z ECMWF position is east of the NHC track but
with a much weaker system than the official forecast. The biggest
outlier is the 12Z UKMET which takes the tropical system into
North Carolina, with no remaining deterministic support and
significantly west of the NHC track.

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

Otto