Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1201 PM EDT Tue Jun 11 2019

Valid Jun 11/1200 UTC thru Jun 15/0000 UTC

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

12Z Model Evaluation...with Confidence and Preferences
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...Great Lakes and Northeast US...
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Preference: Non-GFS, Non-UKMET blend
Confidence: Average

Troughing over the Great Lakes and Northeast US is expected to
amplify/deepen later this week as another shortwave digs into the
lower Great Lakes. Through about the first 36 hours or so
/13.00z/, model agreement is in good shape and above average with
the mass fields. However as the trough axis takes on a negative
tilt Friday, more significant differences are seen in the latest
deterministic guidance. The 00z UKMET is deeper and more amplified
than the rest of the guidance and also a touch slower. Likewise,
the 00z CMC is slow edge of the model spread. The NAM, GFS, and
ECMWF appear to be in decent shape but 14.00z, the GFS becomes
much deeper with the upper level low over the Great Lakes and
while the rest of the models phase with another closed low over
James Bay, the GFS prefers the two systems to stay distinct. This
keeps the GFS on the slower side as the other models push the
initial PV anomaly through New England. Overall, confidence drops
off considerably by Friday into the weekend. At the surface, the
differences are not as significant, but the track of a coastal low
will have considerable QPF placement issues along the East Coast
later this week. Based on all of this, the consensus seems to be
for a non-GFS, non-UKMET blend.


...Western and Southern US...
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Preference: General model blend
Confidence: Slightly above average

Elsewhere across the CONUS (western and southern US), model
agreement is slightly above average with better confidence in the
mass fields. Mid to upper level ridging along the western US coast
will gradually break down as a mid-level wave comes onshore. As
this wave treks across in the southern stream flow, the ECMWF is
on the weaker side of the model spread and also a touch on the
slower end as well. But overall, the guidance shows fairly good
agreement and a general model blend is preferred.


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

Taylor