Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
235 AM EDT Tue Jul 28 2020
Valid Jul 28/0000 UTC thru Jul 31/1200 UTC
...See NOUS42 KWNO (ADMSDM) for the status of the upper air
ingest...
00Z Model Evaluation Including Preferences and Forecast Confidence
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
07Z update: No significant changes noted with the rest of the 00Z
guidance and no changes to the model blend preferences at this
time.
...Mid-upper level troughing over the Great Lakes and Northeast...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: General model blend
Confidence: Above average
Large closed upper level low over Ontario is forecast to settle
over the area through the forecast period with its surface front
marching across the Great Lakes, Mid-Atlantic, and Northeast.
Models have converged on a similar position, strength, and timing
of the synoptic features and a general model blend continues to be
preferred.
...Mid-level energy over Great Basin...
...Energy advancing southeast across the Plains by Wednesday...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: General model blend through 48 hours; ECMWF/CMC/NAM
blend after
Confidence: Average
Mid-level energy over the Great Basin region slips eastward toward
the Rockies and eventually spills out into the Central Plains by
48 hours. Models mostly agree on this evolution through 48 hours,
however afterwards there are some phasing differences noted with
the large upper trough over the Great Lakes. The UKMET separates
this energy the most to the west while the GFS drops the energy
the furthest south and at a faster clip. The consensus is favored
with the ECMWF/CMC/NAM showing the best consistency at this time.
...Upper low/trough approaching the Pacific Northwest...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: General model blend through 48 hours; ECMWF/GEFS/ECENS
blend after
Confidence: Average
Models continue to depict a deepening upper level well offshore
over the eastern Pacific. One particular shortwave trough embedded
in the flow is forecast to swing northward along the coast in the
Wed Night to Thursday time frame. Here the GFS/NAM are
considerably more amplified with the feature and also
significantly faster than the non-NCEP guidance. Looking at the
ensembles, the deterministic runs of the GFS/NAM are probably too
fast at this time. A blend of the ECMWF/GEFS/ECENS is preferred
for day 3.
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml
This product will terminate August 15, 2020:
www.weather.gov/media/notification/pdf2/scn20-58pmdhmd_termination.
pdf
Taylor