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 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...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 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... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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: 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... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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