Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1156 PM EST Mon Jan 27 2020
Valid Jan 28/0000 UTC thru Jan 31/1200 UTC
...See NOUS42 KWNO (ADMNFD) for the status of the upper air
ingest...
00Z Model Evaluation with Preliminary Preferences and Confidence
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...Split flow trough crossing the Mountain West overnight and
reaching the Southeast Wednesday night...
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Preference: 28/00Z GFS and 27/12Z ECMWF/UKMET
Confidence: Average
The latest NCEP runs remains in decent agreement with the synoptic
pattern...although the 28/00Z NAM was a weak and slow outlier by
the end of day 3. The 27/12Z Canadian was clustered better with
the NCEP guidance than it was in previous runs, but it also became
an outlier by 00Z Thursday...leaving the UKMET in decent agreement
with the NCEP guidance even if it was a tad slow. This leaves the
previous model choices pretty much in tact with a combination of
the 28/00Z GFS and the 27/12Z UKMET resulting in a good starting
point for this system...with the NAM and CMC still not preferred.
...Progressive upper trough over the Pacific Northwest and
amplifying into the Southern Plains Wednesday.
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Preference: General Model Blend
Confidence: Average
Yet another in a series of systems moving in from the Pacific will
move onshore later today and then dig into the Southwestern U.S.
on Days 2/3. The models tended to handle the ridge building to
the west of this system over the eastern North Pacific ocean and
that results in a fairly consistent solution downstream as the
trough drops southwest and amplifies near the base of the trough.
The 28/00Z GFS and 17/12Z UKMET remain a bit more progressive
similar to the 27/12Z ECMWF. Given the magnitude of the ridge
building upstream, would tend to stay away from the solutions
which are faster to move the system off the the east. Still think
that trends suggest that a solution somewhere in the middle is the
most probable outcome at this time through 12Z Friday.
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml
Bann