Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 223 AM EDT Thu Aug 02 2018 Valid Aug 02/0000 UTC thru Aug 05/1200 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 00Z Model Evaluation Including Preference and Forecast Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Overall Synoptic Pattern across the CONUS... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: Non-NAM Northeast Pref: 00z ECMWF/UKMET/CMC/GEFS blend Confidence: Slightly above average 07z update: The 00z ECMWF trended favorably towards a greater amplification of the phasing through the Northeast by Sat, supporting a closed surface low in the Gulf of ME; however it remains well slower than the GFS/NAM. Still, it is also supported by the CMC/UKMET though both are not as deep, and the 00z GEFS mean shows greater relative comparisons to the ECMWF than the GFS...suggesting a 00z ECMWF/UKMET/CMC/GEFS blend would work best in the Northeast. Elsewhere, the models continued to show good alignment/continuity across the Central and Northern Plains as well as the deepening stacked low off the Northwest coast. So overall a Non-NAM blend remains preferred. ---Prior Discussion--- The narrow deep latitude trof across the eastern third of the CONUS phases with a strong shortwave rotating around the southern and western side of subtropical ridge before lifting up along the Northeast coast into Sat. The 00z NAM and GFS both are a bit stronger in the mean synoptic trof and so deepen the surface wave into SE Canada late Sat, outpacing the mean ensemble suite (including the GEFS), so would favor a slower solution in mass, toward the ECMWF/UKMET/CMC but a weaker GFS solution is still tenable at lower weighting if desired. A shortwave rounds the Southwestern ridge today into tomorrow,before ejecting into the central Rockies Fri, here the 00z GFS and NAM both slowed a bit to become better timed with the 12z UKMET/CMC while the 12z ECMWF lags a bit. The wave will lift north through MN, in advance of a positive tilt trof crossing the Canadian Rockies into the Central Canada Fri/Sat. The combination of the two waves, will over-amplify with the 00z NAM, which actually outpaces the remaining guidance; and while this trend was noted with the 00z GFS (toward a deeper/compact solution), the 00z GFS trended favorably slower toward the UKMET/CMC. Here a Non-NAM solution would be preferred. Off the Northwest coast, a large closed/stacked low will drop out of the Gulf of AK by Sunday morning. Here a general model blend can be supported at above average confidence. Overall, will favor a Non-NAM blend at slightly above average, but would favor removal hedge away from the GFS in the Northeast...with a bit more uncertainty/confidence in that area. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Gallina