Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1220 PM EDT Wed Sep 18 2019

Valid Sep 18/1200 UTC thru Sep 22/0000 UTC

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

12Z Model Evaluation with Preferences and Forecast Confidence
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...Overall Pattern across the CONUS...
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Preference: General model blend increasingly weighted toward
            ECMWF Ensemble and GEFS Ensemble means by Day 3
Confidence: Average

The synoptic pattern will continue to be dominated by a western
U.S. trough and an eastern U.S. ridge. In general, the models are
in good agreement over the first couple days of the forecast, with
increasing differences by Day 3 (Friday Night and Saturday)
related to how the trough ejects east into the Plains. The 00Z
ECMWF and CMC showed the trough lagging back in the West, while
the 12Z GFS, NAM and 00Z UKMET were faster and less amplified with
the trough. Both scenarios have a reasonable amount of ensemble
support, and the ensemble means are positioned around a median
timing. Therefore, the model preference will be trended toward the
ensemble means by Day 3. This may have an effect on the track of
the remnant circulation of Imelda over the south-central U.S., and
an approach that follows the ensemble means is also preferred for
that system.


Model trends at www.wpc.noaa.gov/html/model2.html
500 mb forecasts at www.wpc.noaa.gov/h5pref/h5pref.shtml

Lamers