Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
242 AM EDT Mon Jun 24 2019
Valid Jun 24/0000 UTC thru Jun 27/1200 UTC
...See NOUS42 KWNO (ADMNFD) for the status of the upper air
00Z Model Evaluation...with Final Confidence and Preferences
...Overall Pattern Across the CONUS...
Preference: General model blend
There were no significant changes noted in the 00Z ECMWF over its
previous 12Z cycle. Changes in the 00Z UKMET/CMC were toward the
remaining model consensus across the Great Lakes where their 12Z
cycles were showing differences discussed below. Otherwise,
uncertain remains high with the smaller scale details along and
east of the Mississippi For Wednesday into Thursday with no major
mass field adjustments noted in the 00Z ECMWF/UKMET/CMC compared
to their previous 12Z cycles.
...previous discussion follows...
A progressive mid-level shortwave will become negatively tilted as
it crosses the Great Lakes Monday night, followed by quasi-zonal
flow between the Great Lakes and the West Coast for Tuesday
morning. The 12Z UKMET stands out as weaker with a low amplitude
wave within this flow over the northern Plains Tuesday morning.
The 12Z CMC stands out with a more southward displaced shortwave
near the Great Lakes Tuesday morning as well. Ensemble agreement
is better suited for a 00Z NAM, 12Z ECMWF and 00Z GFS blend with
only minor timing differences between the 3 models.
Afterward, a large closed low offshore of southern British
Columbia will slowly move south and east, reaching the Pacific
Northwest coastline for the second half of Wednesday. No
significant differences show up with this feature.
The greatest differences come from low amplitude impulses that
emanate from the Great Plains and track eastward, resulting in a
large but broad and ill-defined mid-upper level trough to the east
of the Mississippi River Wednesday night into Thursday morning. No
single model stands out here with differences driven more on the
convective/mesoscale. A general model blend is preferred here with
each model showing reasonable run to run consistency with itself.
Model trends at www.wpc.noaa.gov/html/model2.html
500 mb forecasts at www.wpc.noaa.gov/h5pref/h5pref.shtml