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Model Diagnostics Discussion
(Caution: Version displayed is not the latest version. - Issued 0754Z Jan 25, 2020)
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Geographic Boundaries -  Map 1: Color  Black/White       Map 2: Color  Black/White

Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
254 AM EST Sat Jan 25 2020

Valid Jan 25/0000 UTC thru Jan 28/1200 UTC

...See NOUS42 KWNO (ADMNFD) for the status of the upper air

00Z Model Evaluation with Final Preferences and Forecast Confidence

...Shortwave tracking from the Pacific Northwest to the Mid MS
Valley through Mon...
Preference: General model blend through 48 hours, Non-GFS/CMC day 3
Confidence: Average

A shortwave will race across the CONUS to be near the Atlantic
Seaboard late in the forecast period. The guidance is in good
agreement with this feature racing east then digging southeast
from the Northern Plains into the Mid MS Valley and towards the
Mid-Atlantic coast Monday. Late Sunday into Monday, the guidance
begins to diverge with the speed and intensity of this feature, as
the GFS lags considerably the consensus, while the CMC becomes
sheared in the pinched flow south of a big upper low over New
England. Between the two, the ECMWF/UKMET/NAM are all well within
the ensemble envelope, although the NAM intensity is a bit deeper
than the remaining guidance.

...Shortwave trough crossing the West Coast Sun...reaching the
Southwest Mon...
Preference: Non GFS/CMC blend
Confidence: Slightly above average

Feature is relatively well agreed upon moving into the west coast
Sunday, and then amplifying into a deeper trough across the
Southwest on Monday. The CMC begins to slow to be well west of the
global consensus and at the edge of the ensemble envelope by day
3, while the GFS is in good longitudinal agreement, but is a
considerably deeper solution. The GEFS/ECENS mean along with the
ECMWF/NAM/UKMET are all reasonable as the shortwave evolves into
the Southern Plains.

...Closed mid level low tracking from the Mid MS Valley across
Ohio Valley Sat into the Northeast Sun...
Preference: General Blend through 60 hours, non 00Z NAM/ECMWF
Confidence: Slightly above average

07Z Update: The lagging vorticity maxima which will rotate around
the upper low is now progged by the ECMWF to cross New England
much slower than the remaining guidance and is outside the
ensemble envelope. The ECENS should be used instead of the
operational beyond 60 hours for this feature.

Very good agreement persists in the evolution of a strong closed
low currently across the Ohio Valley lifting northeast slowly
through the weekend. The main core of this feature has good model
consensus that it will drift into New England by Sunday and then
into Southeast Canada Monday. Around the primary low, lobes of
vorticity will rotate cyclonically, and while these features are
hard to time/distinguish beyond the near term, the NAM is the only
true outlier with positioning and intensity of any of these vort
maxima. The UKMET Monday begins to drive the upper low a bit too
quickly to the east, but only towards the end of the period.

Model trends at
500 mb forecasts at