Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 1229 PM EDT Mon Jun 25 2018 Valid Jun 25/1200 UTC thru Jun 29/0000 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 12Z NAM/GFS evaluation ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Western U.S. to the High Plains... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: Blend of the operational models A lead trough will skirt through the northern Rockies and Plains through Wednesday, followed by a more sharply digging trough over much of the West on Thursday. The models are fairly tightly clustered. Recent runs of the GFS, including at 12Z, stand out as being toward the deep end aloft on Day 3. The GFS surface low in the northern Plains is also a little east of consensus by 29/00Z. Thus, be careful using the GFS for the Day 3 details. ...Eastern U.S... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: 12Z GFS with support from the GEFS mean, ECMWF Ensemble Mean A northern stream trough will move downwind of the Northeast states Tuesday, while the trough over the Midwest is reabsorbed into the westerlies and approaches the East Coast. The operational ECMWF and Canadian, as well as associated ensemble members, have occasionally produced some convectively enhanced surface reflections / surface low development / along the East Coast. This is not impossible, but the timing of the convective blow-up in the 00Z ECMWF solution is a little suspect given that widespread overturning is expected over North Carolina Monday evening prior to the arrival of the mid level vort max or MCV from the west Tuesday morning. Overall, the ensemble means are a safer bet here, as noted in the overnight preference as well. The solution that best fits the ensemble consensus is the 12Z GFS, whereas the NAM is a close second but becomes a bit slow by Day 3. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Burke