Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
224 PM EDT Fri Jun 19 2020
Valid Jun 19/1200 UTC thru Jun 23/0000 UTC
...See NOUS42 KWNO (ADMSDM) for the status of the upper air
ingest...
12Z Model Evaluation Including Preferences and Forecast Confidence
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Eastern U.S. closed low and coastal front
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Preference: General model blend
Confidence: Above average
Overall, the deterministic guidance is now in good agreement with
this system -- indicating a closed low developing periodically as
it moves from the Ohio valley to the Mid-Atlantic states Friday
and Saturday, before lifting off of the Mid-Atlantic to the New
England coasts Sunday and Monday.
Closed low developing over northern high plains and parade of
shortwaves across central Plains
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Preference: Non-GFS blend
Confidence: Average
Overall, the deterministic guidance is in good agreement through
late Saturday. By Sunday morning however, the GFS becomes more of
an outlier -- especially with the upper level shortwave and
associated surface low lifting from the mid Mississippi valley
into the Great Lakes. The GFS shows a more amplified upper level
trough and slower surface reflection than most guidance.
Differences continue as this system lifts north of the Great Lakes
into Canada and interacts with the upper low over central Canada.
The GFS shows less interaction between the system with a weaker
shortwave lifting north of the Great Lake toward James Bay while
maintaining a deep low over Manitoba and western Ontario on
Monday. Most guidance shows the shortwave over the Great Lakes
amplifying, with a closed low developing near James Bay while the
system to west gradually weakens.
Troughs approaching the Pacific Northwest through Sunday
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Preference: Non-GFS blend
Confidence: Average
With the shortwave moving from the Pacific Northwest to the
northern High Plains on Sunday, the GFS is more amplified than the
other deterministic models. Otherwise, models show generally good
agreement through the period.
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml
Pereira