Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
132 PM EST Mon Dec 02 2019
Valid Dec 02/1200 UTC thru Dec 06/0000 UTC
...See NOUS42 KWNO (ADMNFD) for the status of the upper air
ingest...
12Z Model Evaluation with Preferences and Confidence
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...Overall Pattern Across the CONUS...
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Preference: General model blend
Confidence: Slightly above average
19Z update: No significant changes to the model preference with
the rest of the 12Z guidance now available. There still is
reasonable agreement with the shortwave troughs over the northern
tier and Northeast U.S. and with the approaching storm system for
southern California and the Southwest U.S. by mid to late week.
Anomalously deep upper trough over the Mid-Atlantic and Northeast
U.S. is well agreed upon with the latest model guidance through
the next 24 to 36 hours and any model differences remain on the
smaller scale and likely driven by mesoscale processes. Other
notable features of interest in the next 3 days include another
shortwave trough moving through the northern Plains and Great
Lakes through Tuesday that will reinforce the large scale
troughing over the eastern U.S. through mid-week. Here, models are
in fairly good agreement though the 12Z GFS is a bit flatter with
the shortwaves by Thursday and therefore faster than the rest of
the guidance. The ECMWF/CMC are on the slower side of the guidance
envelope while the UKMET and the NAM to some degree offer a
compromise solution. Out west, a closed low off the northern
California coast will drop southward and then move inland by 48-60
hours across southern California. Through 60 hours, there is
fairly good agreement with the large scale setup though between
60-84 hours as the wave ejects into the southern/central Plains,
the UKMET is considerably slower. The GFS/NAM offer a more
amplified solution with the shortwave and the ECMWF would be a
good consensus approach at this time. Another significant west
coast system will begin to approach the west coast by the end of
the forecast period /Thursday night/ and at this point, model
guidance is in fairly good agreement. Given the relative good
model agreements (outside typical model biases seen), a general
model blend would suffice for the large scale mass fields.
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml
Taylor