Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
136 AM EST Fri Nov 29 2019
Valid Nov 29/0000 UTC thru Dec 02/1200 UTC
...See NOUS42 KWNO (ADMNFD) for the status of the upper air
ingest...
00Z Model Evaluation with Preferences and Forecast Confidence
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...Deep closed low crossing the Intermountain West/Plains...
...System reaching the Mid-Atlantic by Monday...
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Preference: Non-GFS blend...weighted toward 00Z ECMWF/12Z ECENS
Confidence: Slightly above average
There remain some meaningful model differences with respect to the
deep layered closed low currently evolving over central CA. The
height falls with this system will translate east across the
Intermountain West Friday, and then reorganize and deepen across
the High Plains and Midwest on Saturday along with a notably
strong surface low. Thereafter, the system advances east across
the OH Valley and reaches the Mid-Atlantic region by Monday, with
the attendant area of surface low pressure redeveloping along the
Mid-Atlantic coast. The 00Z GFS once again tends to be a bit
stronger than the remaining suite of deterministic guidance, with
the 00Z UKMET seen as being perhaps occasionally a bit too weak.
The GFS also tends to track its surface low across the Plains and
Midwest a tad south of the multi-model consensus. Although by the
end of the period relative the Mid-Atlantic region, the GFS shifts
its low evolution farther north. For the time being, the
preference will be toward a non-GFS blend weighted toward the 00Z
ECMWF/ECENS mean through the period.
...Upper low approaching the West Coast by Sunday...
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Preference: Blend of the 00Z GFS and 00Z ECMWF
Confidence: Average
By Sunday, a new closed low will be evolving offshore of the West
Coast, including a separate center over the Northwest U.S. which
breaks away and pivots offshore the West Coast. There will be some
binary interaction between the two centers, with most of the
guidance favoring a gradual consolidation of the two systems. The
best model clustering at this point resides with the 00Z GFS and
00Z ECMWF, and since these models have rather good ensemble
support, a blend of these two solutions will be preferred for the
time being.
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml
Orrison