Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
201 PM EST Thu Nov 14 2019
Valid Nov 14/1200 UTC thru Nov 18/0000 UTC
..See NOUS42 KWNO (ADMNFD) for the status of the upper air
ingest...
12Z Model Evaluation with Preferences and Confidence
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...Closed low development over the Southeast...
...Cyclogenesis off the Southeast Coast...
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Preference: Non-ECMWF blend
Confidence: Average
A shortwave will begin to separate out from the westerlies and dig
down across the lower MS and TN Valleys on today, and as this
energy drops southeast across the Gulf Coast states tonight, it
should interact with and capture energy associated with an
ejecting southern stream closed low crossing through south Texas
and the western Gulf of Mexico. The result of this interaction
will be a closed low over the Southeast by Friday, with coastal
cyclogenesis taking place just southeast of the Carolinas.
The 12Z ECMWF has trended a bit more progressive compared to its
previous run, but is still somewhat slower than the remaining
suite of guidance with the surface and mid-level low centers with
this system, with the remaining guidance clustered on a somewhat
more progressive solution off to the northeast relative to the
Southeast coastline. The 12Z GFS and 12Z UKMET are a tad faster
than the global model consensus, but are within the ensemble model
spread and are not considered outliers. The 12Z GEFS mean and 00Z
ECENS mean are more supportive of the non-ECMWF guidance, so a
non-ECMWF blend will still be preferred at this time.
...Strong northern stream trough brushing the Northeast by Fri...
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Preference: General model blend
Confidence: Above average
The models drive a strong northern stream closed low through
southeast Canada through Friday and Saturday, with the southern
portion of the trough brushing the Northeast. The guidance is in
sufficiently good enough agreement for a general model blend to be
preferred.
...Mid-level shortwaves impacting the Intermountain West...
...Trough amplification across the Plains this weekend...
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Preference: General model blend
Confidence: Above average
A relatively weak mid-level shortwave arrives across the West
Coast today while a second shortwave farther north aims toward
Vancouver Island and southern British Columbia by early Friday.
The initial shortwave should dampen out over the Intermountain
region on Friday, but the second shortwave farther north is
expected to drop southeast down across the Intermountain region
and begin to amplify through Saturday. The latest guidance has
converged rather strongly over the Plains and Midwest by the end
of the period as the 12Z ECMWF trended more progressive and is now
in line with the model consensus. A general model blend will be
preferred.
...Closed low development offshore southern California on Fri...
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Preference: General model blend
Confidence: Above average
Additional shortwave energy approaching California later today
will break away and dig southeast to offshore southern California
on Friday, with the guidance supporting a weak closed low
evolution that drops down to west of the Baja Peninsula this
weekend. The guidance is in sufficiently good enough agreement
that a general model blend can be preferred.
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml
Orrison