Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
330 PM EDT Sat Jun 23 2018

Valid Jun 23/1200 UTC thru Jun 27/0000 UTC

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

12Z model evaluation...including final preferences
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...Upper low weakening across the Northeast tonight...
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Preference: General model blend
Confidence: Above average

The models are in very good mass field agreement with this system.


...Upper trough/closed low currently over the interior Northwest,
ejecting out across the Plains/Midwest Monday/Tuesday...
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Preference: Blend of the 12Z GFS/12Z ECMWF/12Z UKMET
Confidence: Average

Convective details vary among all of the model guidance, but
synoptically speaking, there is decent agreement between the 12Z
GFS, 12Z ECMWF and 12Z UKMET with the evolution of the closed low
into the central Plains through Monday night and attendant surface
low. The 12Z NAM was shown to be faster while the 12Z CMC showed
northward differences with its surface low in the Plains on
Monday. This blend holds through through Tuesday as the upper low
approaches the Great Lakes region.

Only minor changes were noted with the 12Z ECMWF/UKMET/CMC
compared to their previous 00Z cycles.


...Upper trough currently over the northern Plains, reaching the
Great Lakes/Ohio valley on Sunday, weakening across the Northeast
Sunday night...
...Upper level trough amplifying into the Northeast by Monday...
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Preference: Blend of the 12Z NAM, 12Z GFS and 12Z ECMWF
Confidence: Average

The biggest differences develop with the amplification of the
upper trough over the Northeast with the 00Z UKMET offset to the
south both aloft and at the surface beginning late Monday. The 12Z
UKMET looks to be in better agreement with the remaining model
clustering but its surface low remains toward the western side of
the spread. The surface low in the 12Z CMC remains displaced south
of the better agreement seen in the ensembles represented best
with a 12Z NAM, 12Z GFS and 12Z ECMWF blend.

Changes noted with the 12Z ECMWF/UKMET/CMC compared to their
previous 00Z cycles were small.


...Upper trough crossing the Northwest Monday/Tuesday...
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Preference: General model blend
Confidence: Above average

No significant model differences were noted with this system. Only
minor changes were noted with the 12Z ECMWF/UKMET/CMC compared to
their previous 00Z cycles.



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

Otto