Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1230 AM EDT Wed Oct 30 2019

Valid Oct 30/0000 UTC thru Nov 02/1200 UTC

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

00Z Model Evaluation with Preferences and Confidence
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...Powerful closed low over the central Rockies Wed...
...Energy crossing the the Plains/Midwest/OH Valley Thurs...
...Cold front/surface wave impacting the eastern U.S...
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Preference: Blend of the 00Z GFS and 12Z ECMWF
Confidence: Average

Vigorous shortwave energy currently dropping down through the
Intermountain West will reach the central Rockies on Wednesday and
foster a very strong mid-level closed low which will cross the
central Plains and portions of the Midwest and OH Valley through
Thursday. As the energy crosses the OH Valley, it is expected to
become negatively tilted and is forecast to then rapidly lift
northeast across the lower Great Lakes and Northeast through
Friday. Multiple waves of low pressure developing along an
attendant cold front will initially evolve over portions of the
TN/OH Valleys by late Wednesday, but these lows will consolidate
into one dominant wave of low pressure which will deepen over the
upper OH Valley on Thursday before lifting up through the lower
Great Lakes and Northeast. 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 model guidance has finally come
into better agreement, and in particular with the 00Z GFS finally
siding with the more consistent 12Z ECMWF with this system. The
00Z NAM from 48 hours onward takes the closed low north of the
global model consensus, and also appears to be too deep as the
energy crosses the Great Lakes and adjacent areas of southeast
Canada. The 12Z UKMET and 12Z ECMWF are relatively close to the
GFS/ECMWF camp with timing, but appear to be overall a little too
weak with their mid-level low centers. There is still some spread
within the GEFS and ECENS members with how deep the height falls
will be, but for now a blend of the 00Z GFS and 12Z ECMWF will be
preferred.


...Next upper trough/front over the Plains/Midwest by Fri/Sat...
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Preference: General model blend
Confidence: Above average

Another strong shortwave trough and associated cold front will
quickly drop southeast across the Plains and Midwest Friday and
Saturday. Model spread is minimal with this next system, so a
general model blend will be preferred.


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

Orrison