Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
251 PM EST Wed Feb 12 2020
Valid Feb 12/1200 UTC thru Feb 16/0000 UTC
...See NOUS42 KWNO (ADMNFD) for the status of the upper air
ingest...
12Z Model Evaluation with final preferences & confidence
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Overall Pattern Across the CONUS
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Preference: General model blend into day 2 (14.12Z), then non-NAM
on day 3
Confidence: Above Average
Phasing of southern stream energy from the weakening/opening
closed low over the Southwest and Southern Plains along with
northern stream shortwave energy dropping southeast of the
Canadian Rockies will act to deepen troughing over the eastern 2/3
of the CONUS in the next couple of days. Meanwhile, ridging aloft
over the western CONUS is expected to break down by= day 2 as
another shortwave trough quickly traverses the Pacific Northwest.
While the bulk of that energy is likely to remain within the
northern stream, a piece is forecast to break off and eventually
form a meandering closed low around Baja toward day 3. The latest
guidance shows favorable agreement across the CONUS particularly
through 48 hours (14.12Z) such that a general model blend would be
more than sufficient for mass field purposes. Beyond that time
frame, compared to the rest of the guidance the 12Z NAM becomes a
decidedly amplified/slow outlier with the mid/upper trough moving
across the eastern US.
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml
Hurley