Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 107 PM EDT Sat Jun 23 2018 Valid Jun 23/1200 UTC thru Jun 27/0000 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 12Z NAM/GFS evaluation...including preliminary preferences ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Upper low weakening across the Northeast tonight... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend Confidence: Above average The models are in very good mass field agreement with this system. ...Upper trough/closed low currently over the interior Northwest, ejecting out across the Plains/Midwest Monday/Tuesday... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: Blend of the 12Z GFS/00Z ECMWF/00Z UKMET Confidence: Average Convective details vary among all of the model guidance, but synoptically speaking, there is decent agreement between the 12Z GFS, 00Z ECMWF and 00Z UKMET with the evolution of the closed low into the central Plains through Monday night and attendant surface low. The 12Z NAM was shown to be faster while the 00Z CMC showed northward differences with its surface low in the Plains on Monday. This blend holds through through Tuesday as the upper low approaches the Great Lakes region. ...Upper trough currently over the northern Plains, reaching the Great Lakes/Ohio valley on Sunday, weakening across the Northeast Sunday night... ...Upper level trough amplifying into the Northeast by Monday... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: Blend of the 12Z NAM, 12Z GFS, 00Z ECMWF Confidence: Average Biggest differences develop with the amplification of the upper trough over the Northeast with 00Z UKMET offset to the south both aloft and at the surface beginning late Monday. The surface low in the 00Z CMC is also displaced south of the better agreement seen in the ensembles represented best with a 12Z NAM, 12Z GFS and 00Z ECMWF blend. ...Upper trough crossing the Northwest Monday/Tuesday... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend Confidence: Above average No significant model differences were noted with this system. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Otto