Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1245 AM EDT Thu Jul 02 2020
Valid Jul 02/0000 UTC thru Jul 05/1200 UTC
...See NOUS42 KWNO (ADMSDM) for the status of the upper air
ingest...
00Z Initial Model Evaluation Including Preferences and Forecast
Confidence
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Closed low exiting New England Thursday and back door front diving
through late Friday
Developing trough near the Gulf Coast Friday
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Preference: General model blend through Friday, then NAM/GFS/ECMWF
Confidence: Moderate
Guidance remains in good agreement with little spread in both the
spatial and temporal evolution of the closed low dropping
southeast away from New England late in the week. By Friday the
closed low opens and is well removed from the East Coast, with the
CMC a bit faster with the progression of the offshore trough. By
Friday night, as a ridge tries to build northeast from the Plains,
a trough digs back into New England, while a secondary trough
develops beneath the ridge axis across the Gulf Coast region. In
New England, a back door front digging southward Friday night into
Saturday features similar timing. Across the Gulf Coast, the
UKMET is much weaker with the trough as it bulges the ridge too
quickly from the west. A blend of the NAM/GFS/ECMWF depicts a
more realistic pattern with better support from the ensemble means.
Deep upper trough/closed low across the Pacific Northwest and
western Canada
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Preference: General model blend through Friday, then
NAM/UKMET/ECMWF blend
Confidence: Moderate
An expansive closed low meandering across far western Canada and
the Pacific Northwest will linger through Friday as multiple
shortwaves rotate around it. This feature is likely to generally
lift northeast into southwestern Canada, leaving just a weak
trough across the Pacific Northwest by Friday. The guidance does
feature subtle differences in the intensity and position of the
individual vorticity centers, but the general mass field shows
good agreement through Friday, with the exception of a faster
solution with the 12Z CMC across Washington with the shortwave
moving inland. By Saturday, the GFS becomes stronger with the
next impulse to come across the Pacific Northwest.
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml
Hamrick