Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
116 AM EDT Sat Aug 31 2019

Valid Aug 31/0000 UTC thru Sep 03/1200 UTC

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

00Z Preliminary Model Evaluation, Confidence, and Preferences
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

...Overall Pattern Across the CONUS...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: Non-NAM blend
Confidence: Above average

The global suite remains in good agreement in a
western-ridge/eastern-trough setup through the next 3 days. While
small scale perturbations in the flow will impact QPF, there is
generally small spread among the majority of the models. The lone
exception is the 00Z/31 NAM which becomes too fast and amplified
with a shortwave moving into the Pac NW on day 2, and lifting into
the northern Plains by day 3. This has the effect of pushing the
associated surface low and cold front too quickly east and too
sharply to the south, and for this reason the NAM is removed from
the preferred blend.

Otherwise, the preference this cycle includes all other available
guidance, accounting for the typical biases.


...Hurricane Dorian...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Please refer to the official National Hurricane Center forecast
track

For the 03Z NHC advisory package, a blend of the UKMET and ECMWF
are most closely aligned, but before 48 hours the NHC track does
lack the global consensus slightly. By 00z/2 the UKMET and ECMWF
are nearly on top of the NHC track however, so these are preferred
to maintain integrity.

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

Weiss