The Weather Prediction Center

Model Diagnostic Discussion

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Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
255 AM EDT Mon Jun 25 2018

Valid Jun 25/0000 UTC thru Jun 28/1200 UTC

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

00Z model evaluation...including preferences and confidence

...Closed low/trough crossing the Plains/Midwest Monday/Tuesday...
...Crossing the Great Lakes/Northeast by Wednesday/Thursday...
...Surface low crossing the Midwest/Great Lakes...
Preference: Blend of the 00Z NAM and 00Z GFS
Confidence: Average

The guidance has reasonably good agreement with the details of the
upper low and associated trough crossing the Plains and Midwest
through Tuesday, and all of the models take the system across the
lower Great Lakes and Northeast through Wednesday and Thursday. 
over the next couple of days, with. However, the 00Z UKMET begins
to become a bit more progressive than any other model as the
system exits the Midwest and moves across areas of the Great Lakes
and Northeast. Toward the end of the period, the 00Z CMC takes its
surface low farthest south, and the 00Z ECMWF becomes the slowest
solution. Based on the latest trends and clustering, a blend of
the 00Z NAM and 00Z GFS will be favored and this is supported by
the latest GEFS mean and ECENS mean.

...Upper level trough affecting the Northeast by Monday...
...Surface low tracking near Nova Scotia by Tuesday...
Preference: Non-UKMET blend
Confidence: Above average

An upper trough will amplify across the Northeast by Monday and
then evolve into a closed low near Nova Scotia through Tuesday.
The 00Z UKMET edges a bit stronger and a little slower than the
remaining models by Monday night as surface low pressure crosses
southeast of Nova Scotia and then begins to pull away to the south
of Newfoundland. Will prefer a non-UKMET blend.

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

An upper trough will cross the Northwest on Monday and Tuesday in
association with an upper low that moves across western Canada.
The guidance overall is in good agreement with their mass fields,
with only very modest timing/depth differences through the period
now seen. Will prefer a general model blend.

...Next upper trough arriving across the West by Thursday...
Preference: General model blend
Confidence: Above average

The models begin to amplify an upper trough into the West by early
Thursday. There is good mass field agreement with this system, so
a general model blend will be preferred.

...Possible coastal cyclogenesis near the Southeast U.S. coast...
Preference: 12Z ECENS mean
Confidence: Slightly below average

There remains a signal in the model guidance for a wave of low
pressure to develop along a stalled front near southeast NC by
Wednesday morning. The energy for this is related to the MCV that
is currently moving through the lower OH Valley and is expected to
cross the southern Mid-Atlantic region over the next couple of
days. The 00Z ECMWF and and 00Z CMC are the strongest solutions.
The 00Z NAM, 00Z UKMET and especially the 00Z GFS are the flatter
solutions. The 12Z ECENS mean though does reflect a signal for a
low, but just not to the extent of the operational ECMWF. The
latest GEFS mean supports the flatter consensus. Will lean toward
the idea of there being at least a weak wave near southeast NC
early Wednesday, and this would be closest to the 12Z ECENS mean
as it appears now that the NAM may be too slow with this system to
lift off the Mid-Atlantic coast by the end of the period.

Model trends at
500 mb forecasts at


Last Updated: 255 AM EDT Mon Jun 25 2018