Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1255 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. The 06Z GEFS and 00Z ECENS member
suites tend to be actually a little more progressive and weaker
than the NAM/GFS camp, but there is spread with the depth of the
trough, and with there is some concern that a somewhat stronger
evolution may come to fruition given the trends seen out of the
NAM and GFS. 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