Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 255 PM EDT Tue Jun 12 2018 Valid Jun 12/1200 UTC thru Jun 16/0000 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 12Z model evaluation...with final preferences ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Upper trough and related surface cyclone tracking from the Mississippi valley/Great Lakes today/tonight, to the East Coast Thursday morning... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model compromise Confidence: Slightly above average Generally similar agreement was noted in the latest model guidance (both deterministic and ensemble), with the 12Z GFS and 12Z CMC on the faster side of the deterministic envelope. The GFS and CMC, however, were not fast enough to exclude them when used as part of a general model blend. ...Shortwave moving across the Pacific Northwest early Wednesday with related cold front emerging into the northern Plains Thursday night... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend Confidence: Average Quasi-zonal flow across the eastern Pacific at the start of the period supports a quicker movement of a shortwave trough and related cold front through the Pacific Northwest on Wednesday. Ensemble trends have supported this quicker movement, but by 00Z/16, the 12Z NAM is fastest of the deterministic guidance with the 00Z CMC slowest. Prefer the middle ground for now given better ensemble support for the middle road approach. The 12Z ECMWF/CMC trended faster, both nearer to the faster 12Z NAM. Differences are now relatively small, with a group of faster models including the 12Z NAM/ECMWF/CMC, and slightly slower models including the 12Z GFS/UKMET. A general model blend is preferred given the shifts seen in the 12Z guidance, with the 12Z UKMET similar to its previous run. ...Closed low likely setting up over the Pacific Northwest Friday night... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend Confidence: Above average Good agreement exists from the 12Z models with a closed low over the Northwest, with the 12Z CMC adjusting to the consensus from its previously northward displaced 00Z cycle by 00Z/16. ...Hurricane Bud... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: non 12Z CMC blend Confidence: See 15Z NHC advisory The 12Z NAM, 12Z GFS and 00Z ECMWF are closest to the 15Z NHC advisory regarding the track of Hurricane Bud as it tracks northward and weakens into the Gulf of California/Sea of Cortez. The 12Z ECMWF adjusted a little faster and west of the NHC track, but only by a little, while the 12Z UKMET trended toward the 12Z NAM, 12Z GFS and 00Z ECMWF positions. The 12Z CMC remains slower with Bud and will not be included in the preference given its difference from the 15Z NHC advisory. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Otto