Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1228 AM EDT Tue Apr 14 2020
Valid Apr 14/0000 UTC thru Apr 17/1200 UTC
...See NOUS42 KWNO (ADMNFD) for the status of the upper air
ingest...
00Z Model Evaluation with Preferences and Confidence
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Eastern half of CONUS
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Model Blend Preference: 12Z ECMWF and 00Z GFS
Confidence: Average
Deep, intense surface cyclone over western Quebec and its
associated cold front over the eastern U.S. will continue to march
steadily eastward through the next 12-24 hours. The southern end
of the frontal boundary is expected to stall/wash out over
portions of the Southeast U.S. and Florida. A secondary area of
low pressure is then forecast to develop along the boundary and
move northeast offshore the Mid-Atlantic coast Wednesday into
Wednesday night. There remains some sizable differences in the
latest model guidance with respect to the north-south extent of
the developing low and how quickly it lifts northeast. The 12Z
UKMET was the slower of the models while the 00Z GFS and 12Z ECMWF
showed some favorable agreement. A look at the ensembles would
support a solution toward the ECENS/ECMWF and away from the slower
UKMET. The 00Z GFS did trend toward the ECMWF, so through 16.00Z,
the GFS can be incorporated across the eastern U.S.
Western/Central CONUS
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Model Blend Preference: Non-NCEP day 2/3
Confidence: Slightly above average
Highly amplified ridge over the Eastern Pacific through the Gulf
of Alaska will result in a blocky pattern and lower predictability
forecast for a developing compact shortwave that rounds its
periphery Tuesday before descending southward just offshore the
Western CONUS. Similarly, another mid-level feature will descend
through the flow from the Canadian Rockies through the
Intermountain West and central Rockies. For the offshore system,
the CMC remains an outlier with its fast progression and
fractional pieces. The GFS looks reasonable offshore but for the
interior shortwave, it ejects the mid-level low too strongly and
thus has too strong of inflow and QPF. The non-NCEP guidance shows
weaker flow and this is supported by the teleconnections with the
anomaly over the eastern Pacific. Overall, a blend toward the
ECENS with components of the 12Z ECMWF appear most reasonable at
this time.
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml
Taylor