Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 1140 AM 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 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Closed low development over the Southeast... ...Cyclogenesis off the Southeast Coast... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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 00Z ECMWF gradually becomes 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 00Z UKMET are a tad faster than the global model consensus, but are within the ensemble model spread and are not considered outliers to the extent that the ECMWF is. The 06Z GEFS mean and 00Z ECENS mean are more supportive of the non-ECMWF guidance, so a non-ECMWF blend will be preferred at this time. ...Strong northern stream trough brushing the Northeast by Fri... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: Blend of the 12Z GFS/00Z CMC and 00Z UKMET Confidence: Slightly 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 12Z NAM overall appears to be a bit too weak with the amplification compared to the global models. Among the global models, the 00Z ECMWF becomes a bit of a slower outlier solution, with the 12Z GFS, 00Z CMC and 00Z UKMET showing better model clustering as the energy ejects east out across the Plains by Sunday. Will prefer a compromise of the GFS, CMC and UKMET solutions at this time. ...Closed low development offshore southern California on Fri... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: Blend of the 12Z GFS and 00Z UKMET 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 good agreement with the height fall evolution through 60 hours, however, beyond this time frame the 00Z ECMWF focuses the closed low closer to the Baja Peninsula, with the 12Z NAM and 00Z CMC much farther west and to the left of the model consensus. The model consensus is best approximated by the 12Z GFS and 00Z UKMET by the end of the period, which is also well supported by the 00Z ECENS mean. So, a general model blend will be preferred through about 60 hours, followed by a GFS/UKMET blend thereafter. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Orrison