Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 1224 AM EDT Wed Jun 13 2018 Valid Jun 13/0000 UTC thru Jun 16/1200 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 00Z Model Evaluation...with Preliminary Preferences and Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Overall model diagnostic analysis for the CONUS... Preference: General blend; greatest weight on 00Z GFS; 12Z ECMWF Confidence: Slightly above average The pattern over the CONUS is gradually shifting to one with stronger synoptic forcing: a trough over the Northeast (reinforced by several shortwaves), a trough in the West with an upper-level low digging down the West Coast, and a broad upper level anticyclone shifting from the Southern Plains into the Mid Mississippi River Valley. Available models all have a fairly good handle on this situation, and are similar in many respects. There are some slight differences; for example the 12Z UKMET digs the low on the West Coast a little more sharply, with slightly more amplification to the trough over the Desert Southwest and slightly more amplification of the downstream ridge. But these differences are relatively minor and do not suggest that any particular model should absolutely be excluded from the model preference. The 12Z ECMWF Ensemble had 500mb normalized standard deviation generally around or less than 1 across the CONUS, which indicates a less spread than average. One concern in the northern tier of states would be with the 00Z NAM and 00Z GFS, and their tendency to significantly ramp up mid-upper level vorticity maxima associated with convection. This does not substantially affect their forecast of the overall pattern, but could influence the timing and placement of QPF. For this reason, other global models are more strongly favored from the Northern Plains into the Northeast, as well as ensemble means, to refine the timing and placement of convective precipitation. ...Hurricane Bud... See NHC for official forecasts for Bud Closest Model Proxy: 18Z GEFS Mean There is a split in the model forecast trends for Bud, with the 00Z NAM, 12Z ECMWF, 12Z UKMET all progressing Bud faster to the north than the NHC forecast, and the 00Z GFS, 18Z GEFS, and 12Z CMC slower. The GEFS Mean was the closest to the official track in its position of the surface low, as the GEFS was a little faster than the deterministic GFS. The ECMWF and UKMET track the low furthest west compared to NHC, which tends to hold the track fairly close to 110W longitude as of the 03Z forecast tonight. The GFS and NAM are closer to the longitude of the NHC track. For official forecast updates on Hurricane Bud, please refer to the National Hurricane Center forecasts. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Lamers