Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1133 AM 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 NAM/GFS Model Evaluation...with Initial Preferences and
Confidence
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...Overall Pattern across the CONUS...
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Preference: General Model Blend, preference to 12Z GFS for Upper
Midwest Day 2.
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. Two surface lows will track through the upper
Midwest, with the second and stronger low affecting 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 northern CA coast this evening with
mid-upper portions of it tracking northeast to the Great Lakes
through Monday. On Day 2 across the northern Great Plains, the 12Z
NAM/GFS have shifted farther north with low track, the NAM more
so, with the NAM also a bit faster. The ECMWF remains the slowest
solution with the UKMET not much ahead, so these are limited in
preference. Preference is given to the 12Z GFS with some 12Z
NAM/00Z CMC recommended.

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 Day 2. Differences do
appear in the track of the Pac NW closed low Monday night into
Tuesday in terms of progression inland. However, given the broad
flow around the low and mountainous barriers, little difference is
seen in the Day 3 precip depiction among global deterministic
guidance, so a general model blend is preferred there too.

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.


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


Jackson