Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1209 PM EDT Thu Jul 05 2018

Valid Jul 05/1200 UTC thru Jul 09/0000 UTC

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

12Z Model Evaluation...with Preliminary Preferences and Confidence
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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

Preference: General model blend
Confidence: Slightly above average

Models are in fairly good agreement over the CONUS with their mass
fields over the next several days. Greater differences exist to
the north in Canada as a wave digs southeast from the Arctic
Circle into central Canada, but the impact on QPF and other
forecast elements in the CONUS is fairly low. Supporting this
model agreement -- the normalized standard deviation of 500mb
heights on the ECMWF Ensemble is generally around or less than 1.0
over the entire CONUS, indicating greater agreement on the
synoptic pattern relative to forecasts over the past 30 days. This
tends to increase confidence.

Given the similarity of the mass fields, a general model blend is
recommended. The primary uncertainties will be related to
convectively influenced boundaries and how they may drive QPF in
future days of the forecast. This is typical of the summer months,
though, and the overall forecast confidence is rated as slightly
above average.

The greatest differences appear to exist with the trough off the
East Coast. The 12Z GFS pushes this east into the Atlantic much
faster than the other models, while the 00Z UKMET shows a strong
upper level low leading to stronger surface cyclogenesis off the
Outer Banks. Therefore, a blend along the East Coast that leans
away from these two models is preferred.


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

Lamers