Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
308 AM EST Sat Mar 07 2020
Valid Mar 07/0000 UTC thru Mar 10/1200 UTC
...See NOUS42 KWNO (ADMNFD) for the status of the upper air
ingest...
00Z Model evaluation with preferences and confidence
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Overall Pattern Across the CONUS
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Preference: General model blend through 09.12Z, then a 00Z
ECMWF/ECENS, 00Z GEFS mean
Confidence: Slightly above average
08Z update: No significant changes/differences noted with the rest
of the 00Z guidance. Preferences remain the same from previous
issuance.
Current synoptic pattern across the CONUS features upper level
troughing over the eastern U.S. and just offshore the west coast
with ridging through the central US. As the ridging works eastward
over the next 24-36 hours, troughing/southwesterly flow is
expected to develop over the western/central US as a couple
shortwaves work through the flow. One shortwave arrives across the
Pacific NW late in the weekend and treks across the northern
Plains early next week. In the southern stream, a weak shortwave
trough moves from southern CA toward the central Rockies/central
Plains early next week, reaching the Great Lakes Tuesday. Finally,
a more anomalous upper level shortwave begins to approach the
southern CA coast by the end of the forecast period /
Tuesday-Wednesday/.
In a broad sense, the latest deterministic guidance agrees well
with continuity and run to run trends as well as well within the
ensemble spread. Through 48 hours (09.00Z) a general model blend
can be used. Beyond that time, the 00Z GFS trends faster than the
rest of the guidance, particularly with the northern stream
shortwave on day 3 as well as the impulse that ejects into the
central Plains. For the closed low off southern CA, the 00Z GFS
did trend slower from its earlier run but still is faster than the
rest of the guidance. The preference then is for a blend toward
the 12Z ECMWF/ECENS mean and 00Z GEFS mean.
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml
Taylor