Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 238 PM EDT Tue Jun 26 2018 Valid Jun 26/1200 UTC thru Jun 30/0000 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 12Z model evaluation...including final preferences ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Western U.S. to the High Plains... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: GFS/ECMWF/UKMET blend Confidence: Above average A couple troughs will move from the West to the northern High Plains over the next few days. In general, the guidance is in good agreement with these systems. By the time the second, and larger, of the two upper waves approaches the High Plains on Fri, the NAM becomes slightly faster than the model consensus, quicker to move height falls into the north central U.S., while the CMC is on the slow side. Thus, those two pieces of guidance are excluded from the preference. ...Eastern U.S... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend Confidence: Above average The latest guidance takes the closed low and associated upper trough over the Midwest gradually east and toward the Mid-Atlantic and Northeast by Thursday. The energy will begin to lift out on Friday as a strengthening upper level ridge begins to set up over the OH/TN Valleys and the Gulf Coast states. Models handle this feature similarly through 12Z Thu. After that time some relatively minor timing/amplitude differences emerge, but with no clear outliers. Thus, a general model blend remains the preference at this time. ...Possible low pressure offshore the East Coast by Wednesday... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: GFS/ECMWF blend Confidence: Average Models seem to have come to a somewhat better consensus with respect to this system, that is generally in the middle of the two camps which were shown previously. The latest ECMWF/CMC runs are slightly weaker than their previous runs, and the UKMET had trended slightly stronger. The NAM and GFS remain on the weaker side of the distribution, but the spread has reduced. A blend between the weaker GFS and the slightly stronger ECMWF seems to appropriately represent consensus, although a general model blend would also be sufficient. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Ryan