Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1236 PM EDT Thu Oct 31 2019

Valid Oct 31/1200 UTC thru Nov 4/0000 UTC

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

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

Eastern U.S. storm through Friday
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: General model blend
Confidence: Above average

An impressive and deep upper level trough and closed low over the
Great Lakes today will keep an active weather pattern in place
through Halloween for the eastern part of the nation.  A strong
cold front trailing south from the surface low will cross the
eastern U.S. and reach the East Coast by later Thursday night. 
The models are now in good enough agreement to merit a general
model blend for this event.

Broad cyclonic flow over the central and eastern U.S. this weekend
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: Non-NAM blend
Confidence: Above average

The next upper level trough settles southward from western Canada
and encompasses much of the central and eastern Plains by Friday. 
Broad cyclonic flow from the Deep South to the Great Lakes will be
in place by Saturday, and an upper level ridge builds in across
the West Coast in response.  The NAM is more amplified and slower
than the model consensus beyond Friday evening, with good overall
agreement among the remaining guidance.


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

Hamrick