Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1207 AM EDT Fri May 10 2019

Valid May 10/0000 UTC thru May 13/1200 UTC

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

00Z Model Evaluation with Preferences and Confidence
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...Overall Pattern Across the CONUS...
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Preference: General model blend
 Exception: Non-CMC in Southwest/closed low
          : Less weight to 12z ECMWF/00z NAM in Midwest
Confidence: Slightly above average

Synoptically the deterministic guidance remains in fairly strong
agreement in the mass fields.   The sharp positive tilt trof in
the Great Basin/Southwest will pinch off into a closed low in the
California Bight later today into Sat under strong agreement.  As
it rolls through far NW Mexico, a typical alignment of
deterministic guidance sets up with the CMC/ECMWF slow, the GFS is
fast; uncharacteristically, the UKMET is weak and slides faster
toward return upslope flow in NM by the end of Day 3.

In the northern stream, a strong jet over-tops the SW Canadian
ridge and drops into the larger scale trof rapidly consolidating
and closing off a low in the upper Midwest/Northern Plains by late
Sat into Sunday.  The 00z GFS slowed a bit, which was a positive
trend (away from typical bias), while also still remaining in the
centroid of ensemble guidance that is further north.  The 00z
ECWMF continues to be on the deeper side of the suite, and while
it is paired with the NAM, it appears to be the only guidance
member that is redirecting the moisture/QPF axis further north
into the Ohio Valley, away from logical trends at this time of
year, when instability drives that axis typically further south,
making it a bit less favored.  The GFS/UKMET and lesser so NAM all
are a bit further southeast with the QPF axis, more in line with
faster flow pressing the upscale growth MCVs and weak southwest
flow waves across the Lower MS into the TN River Valley/southern
Mid-Atlantic.   The 00z NAM continues to be stronger in the
northern stream, typical of late day 3 over deepening solutions,
generating a secondary QPF max near the Midwest.  All in all, the
differences are minor in the synoptic mass fields to support a
general model blend (less CMC in Southwest, less NAM/ECMWF in
Midwest/warm conveyor through TN Valley).  Confidence is slightly
above average in the mass fields, but the QPF axis and influence
of meso/storm scale on QPF reduces confidence there.

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

Gallina