Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1132 PM EST Wed Feb 12 2020
Valid Feb 13/0000 UTC thru Feb 16/1200 UTC
...See NOUS42 KWNO (ADMNFD) for the status of the upper air
ingest...
00Z Model Evaluation with preferences & confidence
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Overall Pattern Across the CONUS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: General model blend into day 2 (14.12Z), then non-NAM
on day 3
Confidence: Above Average
The positively tilted trough over the central US currently
gradually phases with a northern stream shortwave over the next 24
hours and pushes across the east coast Friday into Friday night. A
secondary shortwave then traverses from the Pacific Northwest
through the northern Rockies and Great Lakes through the next 3
days. Finally, another shortwave trough approaches the Pacific
Northwest at the end of Day 3 giving way to quasi troughing over
much of the US by 84 hours. The early 00Z guidance and previous
12Z guidance shows average to above average agreement and
consistency over the last several model cycles such that a general
model blend is more than sufficient through 15.00Z. Beyond that
time frame, the NAM becomes decidedly amplified and slow compared
to the rest of the guidance and falls out of favor, particularly
over the eastern US trough Fri night through Saturday. Looking at
the ensemble means, the NAM is even a step out of phase with
virtually all of the guidance, such it is not recommended for day
3.
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml
Taylor