Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
250 AM EST Wed Feb 05 2020
Valid Feb 05/0000 UTC thru Feb 08/1200 UTC
...See NOUS42 KWNO (ADMNFD) for the status of the upper air
ingest...
00Z Model Evaluation with Final Preferences and Confidence
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...Evolving full latitude trough over the Central US through Thu...
...Surface wave developing over the Lower MS Valley...moving into
the interior Mid Atlantic late
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Preference: non-GFS blend
Confidence: Average to slightly below average
GOES-East WV depicts the full latitude trough across the Center to
Southwestern portion of the CONUS. The northern stream shortwave
is already departing/severing connection to the main elongated
upper level trof. Through 48 hours, the guidance is in reasonable
agreement such that a general model blend can be used. Beyond that
time frame, when the long wave trough begins to take on a neutral
to negative tilt, the 00Z operational GFS races out ahead of the
rest of the guidance. It is also noted that the surface low is
well to the west (inland) compared to the rest of the guidance for
Day 3. This has major implications for QPF and thermals and
overall is not as favored at this time given the higher agreement
between the ECMWF/UKMET/NAM/CMC. The 18Z GEFS mean would also be
good to include as its relatively similar to the other solutions.
...Pulses along atmospheric river Wed-Fri into Pacific NW...
...Approaching rapidly deepening cyclone toward Pacific NW by end
of Day 3...
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Preference: 12Z ECMWF/UKMET and 00Z GFS blend
Confidence: Average
Ridging is expected to persist across the western U.S. through the
first couple of days and then toward Friday/Friday night/Saturday
a rather compact and impressive shortwave trough races into the
Pacific Northwest. Forecast confidence is about average right now
with some notable spread seen in the latest guidance. The CMC is
the fastest outlier solution, well ahead the rest of the
deterministic guidance and the ensemble means. The UKMET/ECMWF
offer a middle ground approach and show relatively similar
strength (ECMWF is a bit stronger) while the 00Z GFS is weaker
(not closed at 500 mb). The NAM is the slowest and strongest
solution. Despite the differences aloft, the 00Z GFS surface
reflection is fairly consistent with the more agreeable
ECMWF/UKMET, so some inclusion of the GFS appears sufficient. With
all this in mind, will lean toward a 12Z ECMWF/UKMET and 00Z GFS
blend for this cycle.
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml
Taylor