Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 303 PM EDT Fri Jul 26 2019 Valid Jul 26/1200 UTC thru Jul 30/0000 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 12Z Model Evaluation and final preferences ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Northern Tier of the U.S... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend Confidence: Slightly above average Models show consensus that two shortwaves should skirt across the CONUS Northern Tier during the short range. The first wave is forecast to move from the Upper Midwest/Great Lakes tonight/early Sat into Ontario Quebec by Sat afternoon, skirting New England by Sun, with the trailing frontal boundary lingering across the north central U.S. The second shortwave and associated cold front are expected to move onshore in British Columbia and the Pacific Northwest early Sat morning, reaching the Northern Plains/Upper Midwest by Sun and the Great Lakes by Mon. 12Z deterministic guidance appear to handle both of these features similarly, and a general model blend is recommended at this time. A wave of low pressure along the cold front moving from the Central Plains to the Midwest Sun-Mon may focus an area of convection along/north of the low track. Given similar synoptic evolutions, model differences in the QPF across these areas appears to be primarily driven by mesoscale/storm scale processes. ...Remainder of the CONUS including the Southwest... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend Confidence: Slightly above average No significant mass field differences were noted with the southwestern ridge and some of the more significant vorticity maxima revolving around the ridge. Regarding the remainder of the U.S., similarly, no significant mass field differences were noted in the latest guidance. Model trends at www.wpc.noaa.gov/html/model2.html 500 mb forecasts at www.wpc.noaa.gov/h5pref/h5pref.shtml Ryan