Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
245 PM EDT Fri Jun 07 2019

Valid Jun 07/1200 UTC thru Jun 11/0000 UTC

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

12Z Model Evaluation...with Final Confidence and Preference
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...Overall Pattern Across the CONUS...
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Preference: 12Z NAM, 12Z GFS, 12Z ECMWF blend
Confidence: Average

...19Z update...

The 12Z ECMWF/UKMET/CMC made nudges toward the preferred middle
ground compared to their 00Z cycles, but most notably seen in the
12Z ECMWF which appears more closely to the 00Z ECMWF and 12Z
NAM/GFS compromise preferred earlier. The final preference will
replace the 00Z ECMWF with the newer 12Z ECMWF while the 12Z
UKMET/CMC continue to show different enough with the
strength/timing of the upper wave to be excluded at this time.

...previous discussion follows...

There will be two main upper level systems to affect the lower 48
through Monday. The first is a slowly weakening closed low moving
east from the lower Mississippi Valley into the Tennessee Valley
while becoming more elongated from north to south. The other
system will come in the form of a progressive shortwave at the
leading edge at the base of a longwave trough over central Canada
into the northern U.S. There is general model agreement with the
system affecting the Southeast.

Regarding the system moving through the north-central U.S. on
Sunday and the Great Lakes on Monday, there are two camps in the
latest deterministic guidance. The 00Z ECMWF/UKMET are a bit more
amplified and wind up with a strong negative tilt at 500 mb over
the Great Lakes on Monday. The 12Z NAM/GFS and 00Z CMC are weaker
and slower to acquire a negative tilt. The surface evolution also
differs correspondingly with a more westward track seen in the 00Z
ECMWF/UKMET. The 12Z GFS is toward the weaker side of the models
with the surface low. Given no significant ensemble clustering or
trends, the preference is to lean toward the middle with a 12Z
NAM, 12Z GFS and 00Z ECMWF blend recommended.

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

Otto