Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1132 AM EST Sat Nov 16 2019
Valid Nov 16/1200 UTC thru Nov 20/0000 UTC
...See NOUS42 KWNO (ADMNFD) for the status of the upper air
ingest...
12Z Model Evaluation with Preferences and Forecast Confidence
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...East of the Continental Divide...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: Non-NAM, non-UKMET blend
Confidence: Average
Two mid/upper level features of note that will be the key players
with the track/evolution of a surface low along the East Coast
through the next few days. Current closed mid/upper level low off
the Southeast U.S. coast will open up and become absorbed into the
deepening longwave trough over the eastern 2/3 of the CONUS. This
is due to a fast moving shortwave trough that becomes negatively
tilted by Monday over the Ohio Valley and Mid-Atlantic. The latest
forecast guidance has come into better agreement through 48 hours
(18.12Z) but there remains some key differences for Day 3. The
most recent GFS trended toward the 00Z ECMWF operational run and
now both of these models are the more offshore solutions. The 00Z
UKMET is the furthest west and the 12Z NAM also is a western
solution. The 00Z CMC lies near the middle of these solutions, but
becomes too slow after 60 hours compared to the rest of the model
guidance. The 12Z GFS and 00Z ECMWF are left/west of their
ensemble means and overall, the ECMWF has been fairly consistent
with its runs the last 3 cycles. With this in mind, the preference
is for a non-UKMET blend with limited inclusion of the NAM for day
3.
...West of the Continental Divide...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: non-CMC blend
Confidence: Average
A strong shortwave trough will approach the Pacific Northwest
early next week. There is reasonable agreement in the latest model
guidance in the strength of the system. However, there remains
some timing differences, where the 00Z ECWMF is a bit faster than
the 12Z GFS, and the 00Z CMC is the slowest. For now, the CMC
appears to be the most outlier solution, and a blend of the other
guidance is likely to yield a reasonable solution for now.
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml
Taylor