Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
331 AM EDT Wed Jun 10 2020
Valid Jun 10/0000 UTC thru Jun 13/1200 UTC
...See NOUS42 KWNO (ADMSDM) for the status of the upper air
ingest...
00Z Final Model Evaluation Including Preferences and Confidence
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...Low shifting northeast from eastern Kansas, crossing the Great
Lakes tonight and merging into a low over northern Ontario through
Thursday...
...Associated cold front moving across the eastern CONUS, reaching
the Eastern Seaboard Friday...
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Preference: 00Z ECMWF/UKMET
Confidence: Average
Good enough agreement on the initial low over eastern KS swinging
northeast through the Great Lakes through tonight. Phasing then
takes place with Cristobal remnants over northern Ontario and the
trailing trough that swings across the Great Lakes and eastern
Ontario has divergent solutions on Day 3. Meanwhile there is
generally good agreement on the cold front pushing east across the
eastern CONUS tonight, stalling near the Eastern Seaboard
Thursday. The 00Z NAM and GFS are the most progressive with the
Great Lakes trough and the 00Z CMC is farther east with the ridge
axis up the Plains. The 00Z greatly slowed its progression of the
Great Lakes trough, but the stronger and farther east ridge
discourages Day 3 precip over the Great Lakes. The 00Z ECMWF and
UKMET are in good agreement with all components of this system
including the degree of positive tilt to the Great Lakes trough
and are therefore preferred.
...Closed low off British Columbia and associated longwave trough
digging and reaching the West Coast by Friday night...
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Preference: Non-GFS 00Z General Model Blend
Confidence: Slightly Below Average
00Z Guidance generally became more progressive with the
reinforcing wave that digs a trough off the CA coast through
Thursday and shifts onshore Friday night. The 00Z GFS remains the
fastest solution with the most open wave that quickly ejects
across the Great Basin Friday night which is well ahead of the 00Z
GEFS mean. The 00Z UKMET is the next most progressive (and similar
to the 00Z GEFS mean), followed by the similar timing of the 00Z
NAM/CMC/ECMWF though the ECMWF is less amplified than the NAM and
CMC. In fact, the 00Z ECMWF make quite a shift from having a slow,
closed low to a much faster open wave. An indication of the
uncertainty with this trough arrival. The Day 3 precip pattern is
affected by the timing and depth of the wave with the deeper
NAM/CMC similar and the more open and faster UKMET/ECMWF/GEFS also
similar and the GFS ahead of everybody. As of now a compromise
between the NAM/CMC and ECMWF/UKMET/GEFS camps is reasonable.
Jackson
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml