Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1249 AM EDT Wed Jul 08 2020
Valid Jul 08/0000 UTC thru Jul 11/1200 UTC
...See NOUS42 KWNO (ADMSDM) for the status of the upper air
ingest...
00Z Model Evaluation with Model Preferences/Confidence
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Closed low moving east across south-central Canada through Friday
Associated cold front crossing the northern Plains
Wednesday/Thursday and the Great Lakes Friday
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Preference: 12Z ECMWF/CMC with some 00Z NAM/GFS
Confidence: Average
A slightly negatively tilted trough axis moving out of the
Northern Rockies and over southern Alberta tonight will continue
to shift east across the Canadian Prairies through Thursday before
opening and lifting northeast over northern Ontario on Friday. The
00Z NCEP guidance was a bit faster and the 00Z NAM ended up
becoming deeper/slower by Day 2 as the systems makes its way into
the northern Plains. The 00Z GFS still slightly outpaces both
with trough progression through the Great Lakes Friday/Day 3, but
is not too far ahead to be totally discounted, just limited in the
blend. The 12Z UKMET is notably flatter than consensus which makes
it an outlier.
Next trough moving into the Pacific Northwest Thursday
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Preference: General Model Blend
Confidence: Slightly above average
The 00Z NCEP models remained in good agreement with other models
from the 12Z cycle with respect to the depth and progression of
this feature into the Pacific Northwest late Thursday. No change
made to the model preference.
Low pressure moving northeast along Eastern Seaboard into this
weekend
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Preference: 00Z NAM and 12Z ECMWF/CMC
Confidence: Average
A fairly weak cyclone is expected to move drift east-northeast
across the Carolinas today before turning northeast up the Eastern
Seaboard on Thursday and Friday. At the same time, a mid-level
ridge builds to the north of the low across the northern
Appalachians and New England. The presence of this ridge continues
to suggest a slower solution. The 00Z GFS remained the most
progressive guidance with the turn north on Thursday...which was
the primary reason that the GFS was not included in the model
preference. The 12Z UKMET is a little less deep with the cyclone
than the 07/00Z run, but is even slower now and a notable outlier.
The 00Z NAM and 12Z ECMWF/CMC remained consistent with their
previous runs and were favored.
Shortwave trough moving across New England Today
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Preference: General Model Blend
Confidence: Above average
Good agreement with this Day 1 shortwave trough crossing northern
New England Wednesday.
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml
This product will terminate August 15, 2020 with the 21Z issuance:
www.weather.gov/media/notification/pdf2/scn20-58pmdhmd_termination.
pdf
Bann