Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1239 PM EDT Mon Mar 11 2019
Valid Mar 11/1200 UTC thru Mar 15/0000 UTC
...See NOUS42 KWNO (ADMNFD) for the status of the upper air
ingest...
12Z Model Evaluation Including Preferences and Confidence
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...Upper trough departing from the Great Lakes/Northeast...
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Preference: General model blend
Confidence: Above average
Only minor differences remain with this system, with a general
model blend recommended to smooth out any smaller scale
discrepancies.
...Upper trough crossing the Pacific Northwest Tuesday...
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Preference: General model blend
Confidence: Above average
The models are in very good agreement in bringing a progressive
northern stream trough in across the Pacific Northwest on Tuesday
before then digging into the Intermountain West where it will
begin to interact with a large southern stream closed low ejecting
out of the Southwest. A general model blend will be preferred with
this system as it advances into the Intermountain West.
...Large closed low crossing the Southwest Monday/Tuesday...
...Phasing with digging northern stream trough...
...Associated deep surface low over the Plains/Midwest...
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Preference: 12Z NAM/GFS and 00Z ECMWF blend...thru 60 hrs
12Z GFS/00Z ECMWF blend...after 60 hrs
Confidence: Slightly above average
A large deep layered closed low just offshore of southern CA will
move east across the Southwest through Tuesday and then eject
northeast out across the central Plains Wednesday where strong
lee-side cyclogenesis will take place. The guidance agrees in
showing strong phasing of this energy with the aforementioned
northern stream trough digging across the Intermountain West. This
will result in a very strong surface low moving from southeast CO
through western/central KS on Wednesday and then northeast across
IA by Thursday. The 00Z CMC and 00Z UKMET are a little weaker than
the overall model consensus with the height falls, at least
through Wednesday which results in a modestly weaker surface low.
The 12Z NAM/GFS and 00Z ECMWF along with a substantial number of
ensemble members favor a stronger/deeper evolution given the
degree of phasing over the High Plains. There is some latitudinal
differences noted as well as the 00Z ECMWF/ECENS mean both support
a low track a tad north of the multi-model consensus, and the it
was noted that the NAM/GFS solutions both slowed their low tracks
down a little compared to their 00Z runs. For now, will prefer a
blend of the 12Z NAM/GFS and 00Z ECMWF through 60 hours, and then
a 12Z GFS/00Z ECMWF blend thereafter as the NAM begins to more
substantially lag the global models with the height fall evolution.
...Upper trough approaching CA by Thursday...
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Preference: 12Z NAM/GFS and 00Z ECMWF blend
Confidence: Slightly above average
The models bring another shortwave trough toward CA on Thursday.
The 00Z UKMET is the slowest solution, with the 00Z CMC the
fastest. The 12Z NAM/GFS and 00Z ECMWF all split the difference in
between, but the NAM is the slower solution of this camp. Will
prefer a 12Z NAM/GFS and 00Z ECMWF blend at this point given
better ensemble support.
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml
Orrison