Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
316 AM EST Wed Nov 27 2019
Valid Nov 27/0000 UTC thru Nov 30/1200 UTC
...See NOUS42 KWNO (ADMNFD) for the status of the upper air
ingest...
00Z Model Evaluation with Preferences and Forecast Confidence
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...Overall Pattern Across the CONUS...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: General model blend
Confidence: Slightly above average
08Z update: Through 60 hours, the 00Z model guidance did not
significant deviate from early 00Z guidance and model trends. The
most notable differences occur at the end of Day 3 with the next
storm system poised to eject out into the central Plains. The GFS
now looks somewhat of an outlier with its far northwest surface
low position at 84 hours compared to the rest of the guidance. The
UKMET trended a bit toward the CMC (southeast solution). For now,
will keep a general model blend preference but the 00Z GFS may
need less weight if trends continue.
Fairly amplified and anomalous synoptic pattern evolving over the
CONUS the next 3 days leads to fairly good agreement with the
latest model guidance. The initial closed, negative tilted low
over the Plains will quickly move through the Great Lakes and off
the Northeast U.S. coast by Thursday. In response, a much stronger
longwave trough will encompass the western U.S. with some ridging
downstream. By the end of Day 3 /Saturday/ pieces of that energy
will eject out into the central Plains and lead to another strong
surface low. Overall, the 500 mb pattern is well agreed upon with
little spread seen in the global deterministic guidance. At the
surface, there is tight clustering with the two current storm
systems. By Saturday, as the next low develops across the central
Plains, there is some latitudinal spread where the GFS is the
furthest northwest (southwest SD) compared to the CMC
(east-central NE). A general model blend would likely yield a
sufficient solution now, where the ECMWF/UKMET seem to be a good
proxy for at this time.
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml
Taylor