Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1214 PM EDT Mon Sep 03 2018

Valid Sep 03/1200 UTC thru Sep 07/0000 UTC

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

12Z GFS/NAM evaluation with preliminary model preferences
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NAM/GFS initialization errors do not seem to degrade their short
range forecasts.


Weakening Western Trough
Front moving across Northern Tier of the country Mon-Thu
Retrograding Upper Trough into FL late Thursday/Friday
~~~~~~~~~~~~~~~~~~~~~~~~
The guidance shows good agreement with the evolution of these
systems.  A compromise of the 00z ECMWF, 12z GFS, 12z NAM, 00z
UKMET, and 00z Canadian is preferred with above average confidence.


Tropical Storm Gordon
~~~~~~~~~~~~~~~~~~~~~
Preference: North of the 00Z ECMWF; See NHC forecasts

The guidance generally agrees on steering Gordon around the
periphery of the subtropical ridge over the Mid-Atlantic States. 
Once inland, the non-NCEP guidance holds onto the system for
longer, which is usually a smart play as the guidance can be too
hasty in dissipating tropical cyclones inland.  The current NHC
track is north of all the available deterministic and ensemble
model guidance, with the 00z ECMWF the closest.  See NHC
discussions for more on the forecast philosophy on Gordon.


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

Roth