Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
300 PM EDT Fri Aug 23 2019

Valid Aug 23/1200 UTC thru Aug 27/0000 UTC

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

12Z Final Model Evaluation Including Preferences and Forecast
Confidence
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...Overall Pattern Across the CONUS...
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Preference: General Model Blend
Exception:  12Z UKMET/ECMWF FL and off Carolinas Days 2/3.
Confidence: Average

Strong model agreement with the synoptic flow across North America
begins to diverge Sunday night due to shortwave trough influences
on the trough moving southeast and from track/development of
individual low centers, both off the Northeast and the tropical
center off Florida starting Saturday night. The 12Z GFS remains
slightly more amplified and progressive with the north-central
CONUS which results in Day 3 QPF farther northeast (most notably
over MI) than 12Z consensus with the 12Z ECMWF the farthest south.
All guidance shifted farther east with the trailing low over the
Northeast CONUS Sunday to the Canadian Maritimes through Monday
with the 12Z GFS still a bit farther east.

All 12Z guidance slowed the system moving north from southern FL
with the 12Z ECMWF and UKMET still practically in lockstep with a
farther out to sea solution. Therefore, the preference with this
system off the southeast coast remains with the latest UKMET/ECMWF.

Some timing differences with the remnants of TS Ivo begin on Day 3
with the 12Z ECMWF the most progressive as it moves north.
However, little difference is noted with the moisture advection
into the Desert SW which mainly occurs through Day 2 when guidance
is in good agreement.

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

Jackson