Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
234 PM EDT Sat Aug 03 2019

Valid Aug 03/1200 UTC thru Aug 07/0000 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

Models are in fairly good agreement across the CONUS over the next
few days. The synoptic pattern remains relatively consistent, with
a persistent ridge in the Western U.S. and a trough over the East
that gets reinforced by some digging shortwave embedded within
deeper layer northwest flow aloft.

The primary differences are related to the trough amplitude in the
Southeast and Gulf of Mexico on Monday and Tuesday. The 12Z
NAM/GFS and 12Z GEFS mean just like their previous cycles tend to
show at least a modestly more amplified trough, while the 12Z
non-NCEP guidance led by the UKMET, CMC and ECMWF are a tad
weaker. The European and Canadian ensemble members tend to favor
the slightly less amplified trough, but given the strength of the
deep layer ridge over the Four Corners region of the country, a
relatively strong teleconnecting downstream trough per the NAM and
GFS is certainly feasible and cannot be ruled out.

One other difference of note is that the 12Z UKMET is a tad slower
with the cold front evolution across the upper Midwest by late
Monday and Tuesday, and has a somewhat stronger surface low riding
along it compared to the other models.

Based on the latest model clustering and ensemble data sets, a
general model blend should still suffice across the CONUS for the
model mass field preferences.


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

Orrison