Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
211 AM EST Mon Feb 03 2020
Valid Feb 03/0000 UTC thru Feb 06/1200 UTC
...See NOUS42 KWNO (ADMNFD) for the status of the upper air
ingest...
00Z Model Evaluation with Latest Preferences and Confidence
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...Deep longwave trough evolving over the Western U.S. this week...
...Surface wave activity developing over the lower/mid MS Valley...
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Preference: Blend of the 00Z ECMWF/UKMET/NAM and 18Z GEFS mean
Confidence: Slightly above average
07Z update: With the rest of the 00Z guidance now available, the
spread seen in the developing trough across the Southwest and
southern Plains through mid-week has lessened somewhat. The 00Z
CMC remains the slower outlier and the GFS a faster solution, but
the differences are noticeable less compared to the previous 2
model runs. The UKMET/ECMWF (and the NAM to some degree) remain a
favorable consensus at this point, though some inclusion of the
GFS is sufficient through 48 hours.
Shortwave trough coming onshore the western US currently is
expected to drop southeast toward the Four Corners over the next
24 hours. The 00Z GFS continues to be very progressive with the
trough as it ejects into the south-central Plains in the Day 2/3
time frame. Looking at the 18Z GEFS, the operational GFS is faster
than any of the ensemble means, and the GEFS mean is reasonably
close to the operational UKMET/ECMWF. So while the deterministic
GFS is an outlier, there is some utility in the GEFS mean.
The 00Z NAM trended somewhat slower and now lines up more
similarly to the ECMWF/UKMET and now has some utility and can be
incorporated (at least from a mass field perspective). Finally,
the CMC remains a slower/deeper solution with its 500 mb heights
digging way to the south/southwest (and overall slower
progression). With all in this mind, will lean toward a
ECMWF/UKMET blend with some inclusion of the 18Z GEFS mean and 00Z
NAM.
...Northern stream energy traversing the northern Plains/Great
Lakes...
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Preference: non-GFS blend
Confidence: Slightly above average
Northern stream troughing is expected to clip parts of the
northern Plains, Great Lakes, and northern New England through
Wednesday. Overall, the guidance shows fairly good agreement with
the differences more subtle than large scale. Toward the end of
the forecast period, the 00Z GFS lies ahead of the rest of the
guidance. The non-NCEP models generally have better support from
the GEFS/ECENS means with this energy, and overall with the lead
energy outside of the UKMET. So, with the GFS camp relatively out
of tolerance, the preference will be toward a blend of the 12Z
ECMWF/GEFS mean and 12Z ECENS mean with the northern stream energy
going through midweek.
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml
Taylor