Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
238 PM EDT Sat Jul 06 2019

Valid Jul 06/1200 UTC thru Jul 10/0000 UTC

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

12Z Model Evaluation...with Confidence and Preferences
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...Overall Pattern Across the CONUS...
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Preference: General model blend
Confidence: Average

For the general synoptic pattern across the CONUS, the main
features involve a closed upper low over the Pacific Northwest
which will eject east over the next couple of days and cross the
northern Plains Monday and Tuesday. Also, there will be a broad
and rather flat trough across the Northeast through the weekend
which gets reinforced early next week as strong height falls
set-up over eastern Canada. Meanwhile, a rather strong mid-level
ridge over the southern Plains and western Gulf Coast region is
expected to generally remain intact although some gradual
flattening/weakening of this is expected by early next week. Areas
a little farther east across the Southeast and central/eastern
Gulf Coast region will come under the influence of weak mid-level
shortwave/MCV-related energy dropping down from the TN Valley
which will foster a broad weakness across this region along with a
broad area of surface low pressure.

Overall, the latest model guidance handles these features
similarly, but there is some meaningful spread noted by Tuesday
with the energy ejecting across the northern Plains. The 12Z
NAM/GFS solutions have been tending to trend stronger with these
height falls and support stronger low pressure here at the surface
compared to the non-NCEP models. Although, it should be noted that
the 12Z UKMET and 12Z ECMWF did trend a bit stronger compared to
the their 00Z runs. The 12Z CMC is overall the weakest solution.
The non-NCEP models also are all a little more progressive, since
collectively they are still weaker than the NAM/GFS camp. The 12Z
GEFS and 00Z ECENS member suites tend to be actually a little more
progressive and weaker than the NAM/GFS camp, but there is still
spread with the depth of the trough, and there is some concern
that a somewhat stronger evolution may come to fruition given the
latest global model trends. For now, will recommend a general
model blend across the CONUS to account for the weaker/stronger
camps across the northern Plains, and also with the remaining
features across the CONUS appearing to be reasonably well-resolved
and well within the ensemble spread of guidance.


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

Orrison