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Model Diagnostics Discussion
(Caution: Version displayed is not the latest version. - Issued 0634Z Sep 25, 2018)
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Geographic Boundaries -  Map 1: Color  Black/White       Map 2: Color  Black/White

Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
234 AM EDT Tue Sep 25 2018

Valid Sep 25/0000 UTC thru Sep 28/1200 UTC

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

00Z Model Evaluation...with Preferences and Forecast Confidence

...Overall preference for the entire CONUS...
Preference: Blend of 00Z GFS, 00Z ECMWF, 00Z UKMET
Confidence: Slightly above average

---06Z UPDATE---
No change to the preliminary preference for the final WPC QPF.

The synoptic pattern over the remainder of the work week should be
relatively static, with a longwave trough over the central US
becoming gradually broader, a ridge anchored along the East Coast,
and a rex block off the West Coast. Given the amplified pattern
and only very gradual change to the mid-upper level flow, the
model agreement is fairly good. The deterministic models' mass
fields are within the model spread envelope, and the spread is
generally not too large.

Therefore, the preference is to lean toward a general blend with
two exclusions. First, the 00Z NAM shows substantially more
amplification to a digging shortwave on the back side of the
longwave trough from the Intermountain West to the Southern
Plains. This is not supported by any other models at this time.
Second, the 12Z CMC has more substantial deviations from the
consensus in its mid-upper level height forecasts by Thursday and
Friday across the CONUS.

Model trends at
500 mb forecasts at