Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 306 AM EDT Tue Jul 07 2020 Valid Jul 07/0000 UTC thru Jul 10/1200 UTC ...See NOUS42 KWNO (ADMSDM) for the status of the upper air ingest... 00Z Model Evaluation with Model Preferences/Confidence Intervals ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NAM/GFS initialization errors do not seem to degrade their short range forecasts. New trough moving into the Pacific Northwest Thursday ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: Model Blend Confidence: Slightly above average The guidance shows general agreement with the depth and progression of this feature into Thursday evening, although the 00Z GFS was a bit deeper and quicker than the 00Z ECWMF. Given the model agreement, a blend should result in a consistent large-scale picture while minimizing some of the minor timing differences. Closed low moving east along the western & central US/Canadian border ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~ Preference: Non-NAM compromise Confidence: Slightly above average The guidance shows good agreement with this feature moving east from the Pacific Northwest through later tonight before the 00Z NAM becomes a slow/deep outlier in south-central Canada -- much like it did in the 12Z model cycle. Since the flow pattern in which it is embedded is fairly zonal, will prefer a compromise of the latest GFS/ECMWF and Canadian with slightly above average confidence. Deep layer cyclone edging east-northeast near the VA/NC border ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: Model Blend Confidence: Above average A deep layer cyclone is expected to move slowly east-northeast as a mid-level ridge builds to the north across the northern Appalachians and New England. A progressive ridge moving over the top of the system argues for favoring a solution on the slower side of the guidance. Still prefer a compromise of the latest GFS/NAM/UKMET with above average confidence. Shortwave trough moving by New England Wednesday Weakening 700 hPa trough across NV/CA through Thursday ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The guidance shows good agreement with the progression and depth of these features, so prefer a compromise of the 00Z NAM, 00Z GFS and the 00z ECMWF with above average confidence. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Bann