Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 436 PM EDT Mon Jun 17 2019 Valid Jun 17/1200 UTC thru Jun 21/0000 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 12Z Final Model Evaluation...with Confidence and Preferences ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...central and eastern CONUS... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend Confidence: Average ...20Z update... No significant changes were noted in the 12Z ECMWF/UKMET/CMC across the CONUS compared to their previous 00Z cycles, but the 12Z ECMWF did trend quicker with the shortwave nearing the northern Appalachians on Thursday, nearer to the remaining model consensus. Enough adjustment was made to include it as part of a general model blend. ...previous discussion follows... A low amplitude mid-level trough extends across the north-central U.S. along with a broader mid-level trough over the Southwest. Embedded smaller scale circulations exist within the flow. There is generally good agreement with the progression of these features but one that stands out with more significant differences is with a shortwave nearing the Appalachians on Thursday. This trough axis is slower in the 00Z ECMWF by Thursday afternoon with affects its surface low placement. The 00Z ECMWF and its ensembles are alone in depicting a slower trough/surface low progression through Ohio into Friday morning with good agreement outside of the 00Z ECMWF. Therefore, a blend comprised of non 00Z ECMWF weighting is recommended toward the end of the short range out east with a general model blend working elsewhere. ...western CONUS... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: non 12Z GFS blend Confidence: Average ...20Z update... No significant changes were noted in the 12Z ECMWF/UKMET/CMC compared to their previous 00Z cycles, making the 12Z GFS stand out from the remaining consensus. ...previous discussion follows... Toward Wednesday into Thursday, there is good model agreement with a closed low which is forecast to reach southern Alberta/Saskatchewan/Montana by 00Z/21. There is good agreement until late Wednesday at which point the 12Z GFS begins to diverge southward from the remaining model consensus. The UKMET/CMC have had poorer run to run consistency with individual vorticity centers surrounding the closed low but their large scale placement agrees with the latest 00Z ECMWF and 12Z NAM. A 12Z NAM/00Z ECMWF blend is preferred with this system which has better ensemble support. Model trends at www.wpc.noaa.gov/html/model2.html 500 mb forecasts at www.wpc.noaa.gov/h5pref/h5pref.shtml Otto