Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1214 AM EDT Sun Jul 07 2019

Valid Jul 07/0000 UTC thru Jul 10/1200 UTC

...See NOUS42 KWNO (ADMNFD) for the status of the upper air
ingest...

00Z Model Evaluation...with Confidence and Preferences
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...Overall Pattern Across the CONUS...
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Preference: General model blend
Confidence: Average

The synoptic pattern across the CONUS is expected to feature a
closed low over the Pacific Northwest that opens up as it moves
into the northern Rockies and northern Plains. Lowering heights
will bring troughing to the Northeast U.S. and Mid-Atlantic region
while brief ridging develops in between over the Upper Midwest. By
Day 3 /Tuesday/ there are indications the energy from the Pacific
NW will deepen into another closed low over North Dakota. At the
surface, the main features will be a developing storm system and
area of low pressure over the northern Plains by Day 3. Areas a
little farther east across the Southeast and central/eastern Gulf
Coast region will come under the influence of weak mid-level
shortwave/MCV-related energy dropping down from the TN Valley
which will foster a broad weakness across this region along with a
broad area of surface low pressure.

The model guidance is in fairly good agreement with the large
scale features, particularly the upper level pattern. The main
issues revolve around timing and strength with the typical biases
seen. The first is the with the energy ejecting out into the
northern Plains by Day 3, where the GFS is faster than the rest of
the guidance. The NAM is stronger, closing off at 500 mb earlier
than the rest of the guidance (although the 12Z UKMET does hint at
this happening as well). This also affects the surface pattern,
where the NAM and UKMET suggest a much stronger low developing
compared to the weaker ECMWF/CMC and to some degree the GFS. For
now, will recommend a general model blend to account for the
typical model biases, especially given the biggest differences are
on day 3.


Model trends at www.wpc.noaa.gov/html/model2.html
500 mb forecasts at www.wpc.noaa.gov/h5pref/h5pref.shtml

Taylor