Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
252 AM EDT Fri Jul 06 2018

Valid Jul 06/0000 UTC thru Jul 09/1200 UTC

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

00Z model evaluation...with final preferences
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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

Overall Preference: 00Z ECMWF
Confidence: Average

The greatest area of uncertainty is in southern Canada where a
pair of shortwaves will be crossing over Alberta and Saskatchewan
Saturday night. Run to run consistency in the guidance has been
poor and ensemble spread is large. The impacts on the U.S. relate
to a cold front in the northern Plains/upper Mississippi Valley on
Sunday with the 00Z GFS the most aggressive with the frontal
boundary pushing south. Here, a 00Z ECMWF/00Z UKMET blend was
favored with the ECMWF not changing much from its 12Z cycle and
the 00Z UKMET adjusting toward the ECMWF.

In the western Atlantic, NHC is still monitoring the possibility
of a tropical cyclone with a 50% chance of development over the
next 5 days via the 00Z Tropical Weather Outlook. With this
system, the 00Z UKMET and 00Z CMC are strongest by Monday morning
off of the Carolinas as the system interacts with a frontal
boundary, and the 00Z GFS is closest to the coast but not as
strong as the UKMET/CMC. The 00Z ECMWF is closest to the ensemble
means with ensemble scatter low plots showing very weak support
for a defined low through Monday morning near the East Coast.

Elsewhere, there is good agreement with the remaining systems
across the lower 48 through Monday morning and 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 average.

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

Otto