Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
230 PM EST Sat Feb 02 2019

Valid Feb 02/1200 UTC thru Feb 06/0000 UTC

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

12Z Model Evaluation...with Final Preferences and Confidence
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...Overall Pattern across the CONUS...
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Preference: General Model Blend
Confidence: Average

An active pattern will persist across much of the western and
northern CONUS through Tuesday. The West will remain most active
as a series of three mid-upper level waves to cross the region
from the Pacific. Low pressure will track through the northern
Plains to Great Lakes Sunday night into Monday. Across the
Southeast, cyclogenesis will occur Sunday along a coastal boundary
off the coastal Carolinas with rainfall generally limited to
eastern NC.

A closed low reaches the San Francisco Bay area this evening with
mid-upper portions of it tracking northeast to the Great Lakes
through Monday. On Day 2 across the northern Great Plains, all 12Z
global deterministic guidance shifted north with low track with
the 12Z GFS the farthest south at 4/12Z. Timing consistency
improved in the 12Z suite with the ECMWF remaining the slowest
solution and the NAM the fastest, so these are limited in
preference. Preference is given to the 12Z GFS with some 12Z
CMC/UKMET included.

Generally good agreement in the latest deterministic guidance with
a trough from a remnant closed low swinging into CA as it is
absorbed into the closed low shifting south from the Pac NW and a
general model blend is preferred there for Sunday night.
Differences do appear in the track of the Pac NW closed low Monday
night into Tuesday in terms of progression inland. The 12Z NAM is
the farthest west with mid level trough stalling over the northern
CA coast while the 12Z GFS is farthest inland over OR. The 12Z
ECMWF is a good compromise for heights given it's position between
the NAM and GFS at 6/00Z. A non-NAM solution is recommended there
for Day 3.

Off of the Carolina coast for Day 2, consensus seems to be nearing
with a surface low developing along the western Gulf Stream
boundary off Cape Hatteras. The 12Z GFS has shifted its low and
associated rainfall west which is in good agreement with the rest
of global deterministic guidance. A tight precipitation corridor
is expected to mainly affect eastern NC per a general model blend.
The only true outlier in terms of continental precip is the 12Z
CMC which is not preferred out of a general model blend for Day 2
there.


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


Jackson