Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1210 PM EST Fri Nov 08 2019
Valid Nov 08/1200 UTC thru Nov 12/0000 UTC
..See NOUS42 KWNO (ADMNFD) for the status of the upper air
ingest...
...12Z NAM/GFS Evaluation with Preliminary Preferences and
Confidence...
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...Shortwaves cutting into the Pacific Northwest Ridge...
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Preference: 08/12Z NAM/GFS..08/00Z ECMWF blend with increasing
weight to ECMWF on Monday
Confidence: Slightly Below Average
The latest guidance continues to show differences on the temporary
breakdown of an anomalous eastern Pacific ridge through
Saturday...with the models showing convergence in solutions
compared to yesterday. The 08/00Z UKMET looks to be the most
aggressive with a favored model blend represented by a 08/00Z
ECMWF and 08/12Z NAM/GFS blend.
Attention then turns downstream across the north-central CONUS as
troughing advancing south from central Canada reaches the Northern
Tier on Sunday. The 08/12Z GFS continued to move towards the model
consensus compared to yesterday but continues to lie on the
envelope of solutions for depth/strength of the 500 mb height
amplification across the western High Plains and the north central
U.S. from Sunday into Monday. Timing differences with a related
cold front through the Great Plains show the 00Z GFS as the
fastest while the 07/12Z and 08/00Z UKMET makes up the other end
of the spectrum with a slower progression. Think the combination
of the 08/00Z ECMWF and 08/12Z NAM appeared to be a favorable
blend early on...but the NAM begins to lag in timing. The
question remains whether or not to include the GFS. For the
moment, think the idea of the previous shift towards including
more ECMWF is still valid but will re-evaluate.
...Remainder of overall pattern across the CONUS...
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Preference: General model blend
Confidence: Slightly above average
A ridge-trough pattern from west to east starts off the short
range period. There is flattening of the flow into Saturday
evening with a fast upper level flow setting up from the Pacific
Northwest into the Mid-Atlantic region. Amplification begins again
by Monday morning with strong ridging along the West Coast and
downstream troughing into the north-central CONUS. A general
model blend should address any minor timing differences between
individual models.
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml
Bann