Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1151 PM EST Thu Mar 05 2020
Valid Mar 06/0000 UTC thru Mar 09/1200 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 07.12Z, then a GFS/ECMWF
blend after
Confidence: Slightly above average
Closed upper level low currently over the Great Lakes region will
gradually fill/weaken over the next 24 hours as it moves toward
the Mid-Atlantic/Northeast followed by some
strengthening/regeneration offshore associated with a deepening
surface low lifting from Cape Hatteras toward the north/northeast.
The low clusters are fairly packed with the east coast low with
respect to its potential depth, but there is some spatial/temporal
spread where the GFS is a bit faster at 36 hours (07.12Z), similar
to the 12Z UKMET, while the 00Z NAM is the slowest (further
southwest at the same time) while the ECMWF/CMC offer a consensus
approach. Through 60 hours, the GFS remains a faster solution.
From a sensible weather perspective, the westward footprint of QPF
varies, especially across southern New England. The CMC offers a
further west solution while the GFS/ECMWF keep the bulk of the
heaviest QPF just offshore. This seems to be the favored approach
based on model run to run trends and continuity.
In the wake of that system, upper level ridging and surface high
pressure dominates much of the central/eastern CONUS. Toward the
end of the end of the period, a shortwave trough approaches the
Pacific Northwest where the NAM is racing out ahead of the rest of
the guidance while the ECMWF lags somewhat. A closed upper level
low then meanders off the California coast at 84 hours, but its
influence on sensible weather holds until after the period.
Overall a general model blend is favored through 36 hours, then
given some of the typical biases in the northern stream, a
ECMWF/GFS blend is preferred.
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml
Taylor