Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 225 AM EDT Tue Apr 10 2018 Valid Apr 10/0000 UTC thru Apr 13/1200 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 00Z model preferences with confidence intervals ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NAM/GFS initialization errors do not seem to degrade their short range forecasts. System carving out in the Rockies/Intermountain West Thu ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: ECMWF/UKMET/Canadian blend; confidence slightly above average The 00z GFS/00z NAM are quicker/broader with the mid-level cyclone emerging into the Plains, which is notable in their surface low latitude/progression. As the flow pattern in which the system is embedded is amplifying, a somewhat sharper and slower position would normally be preferred -- this rules out the NAM/GFS as too quick. The 00z ECMWF/00z UKMET/00z Canadian are closer to the 12z ECMWF/00z GEFS means so they appear reasonable -- a compromise of the three is preferred with average confidence. Northern Plains/Great Lakes/Northeast Low Wed/Thu ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: Model blend; confidence slightly above average The deterministic guidance spread fits nicely within the 12z global ensemble guidance with the surface low position, and the 00z ECMWF QPF has fallen more in line with the other guidance across MN. Believe a compromise of the 00z Canadian, 00z UKMET, 00z NAM, 00z ECMWF, and 00z GFS appears best with slightly above average confidence. For more QPF details, see the WPC QPF discussion. Front moving through Michigan Wednesday New England shortwave into Tuesday ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The guidance is in good agreement with these systems. A compromise of the 00z ECMWF, 00z Canadian, 00z UKMET, 00z GFS, and 00z NAM is preferred with above average confidence. Shortwave moving through the Southeast Tuesday/early Wed ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: Non-NAM blend; confidence slightly above ave The 00z NAM remains a deep outlier with this system. Since it is embedded within a flow pattern with broad wavelength, a broader shortwave representation makes more sense. A compromise of the 00z ECMWF, 00z Canadian, 00z UKMET, and 00z GFS is preferred 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 Roth