Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
351 PM EDT Wed Aug 07 2019

Valid Aug 07/1200 UTC thru Aug 11/0000 UTC

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

12Z Model Evaluation with Final Preferences and Confidence
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

...Overall Pattern Across the CONUS...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: General model blend
Confidence: Average

Model mass fields are in very good agreement into Friday Night,
with the main issue being QPF placement and magnitude along a low
moving cold front over the south-central CONUS on Friday and ahead
of another cold front over the northern Plains on Saturday. A
broad-based model blend is preferred for mass fields with higher
resolution for QPF given their ability to place convective precip
farther toward instability pools.

A cold front stalls over the south-central CONUS late Friday with
associated precip for Day 2 varied in placement and magnitude
along this front. The 12Z NAM nest is the farthest south with this
precip which is farther into the instability pool which is typical
of convective allowing models vs global deterministic.

Differences in the synoptic scale begin to emerge Friday night
with the progression of a trough into the West Coast. The 12Z GFS
is the most progressive inland which would create differences in
shortwave trough progression downstream around the northern high
plains ridge axis to the trough over the northeast CONUS. However,
little QPF difference is noted between the 12Z GFS and the rest of
the 12Z consensus, so a general model blend is recommended.


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

Jackson