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Model Diagnostics Discussion
(Latest Discussion - Issued 0656Z May 23, 2019)
Version Selection
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Abbreviations and acronyms used in this product
Geographic Boundaries -  Map 1: Color  Black/White       Map 2: Color  Black/White

Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
256 AM EDT Thu May 23 2019

Valid May 23/0000 UTC thru May 26/1200 UTC

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

00Z Model Evaluation Including Preferences and Forecast

...Overall CONUS Overview...
Preference: General model blend
Confidence: Slightly above average

07z update: No significant changes noted with the rest of the 00z
guidance now available. Overall a general model blend is still
preferred across the CONUS.

---previous discussion---
Fairly persistent pattern expected across the CONUS through the
next 3 days with a closed low over the interior west while a
strong ridge anchors over the southeast US. Broad southwesterly
flow will intersect these anomalies with several subtle shortwaves
and periodic returns of Gulf moisture.

The first shortwave currently over the Upper Midwest will quickly
move east, riding the building southeast US ridge, and move into
the Northeast US by Thursday night. This system has above average
agreement in the model guidance in the mid/upper levels as well as
at the surface as its low track through upstate NY, New England,
and off the coast of Maine Friday morning.

The next shortwave lifts from Utah, Wyoming then into the Northern
Plains Friday. Outside of the NAM, which is much faster, the rest
of guidance is in fairly good agreement. As this system moves into
Canada, it will allow another closed low to drop down the western
US coast, all helping to lock in the trough west / ridge east
pattern across the CONUS. So, in the large scale synoptic sense,
the pattern is fairly agreed upon with the model guidance. The
differences will lie in the middle with the southwest flow across
the southern/central Plains, which is likely to continue to see an
active pattern with convective systems and potential for high QPF

For the mass fields, a general model blend is acceptable, though
by day 3, a lean on the GFS/ECMWF is preferred.

Model trends at
500 mb forecasts at