Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 246 PM EDT Sun Mar 10 2019 Valid Mar 10/1200 UTC thru Mar 14/0000 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 12Z Model Evaluation Including Initial Preferences and Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Positively tilted shortwave trough moving east into Manitoba and Ontario into Monday morning... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend Confidence: Average Only minor timing/depth differences remain with this system. The 10/12Z NCEP runs and the 10/00Z ECMWF still had the support of the latest ensemble means. The 10/12Z UKMET/CMC. A general model blend should handle these differences adequately. ...Surface low tracking north of the Great Lakes this evening ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend Confidence: Average Differences with this system are small enough such that a general model blend can be used. ...Large closed low forming just offshore of California Sunday night and tracking through Arizona and New Mexico to Kansas on Wednesday ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: 10/12Z GFS/NAM/ECMWF blend Confidence: Average The model agreement is pretty good through the Day 2 forecast period with respect to the track of the closed low. However, spread opens up towards the end of Day 3 as the mid-level center makes a curve towards the north/northeast and takes on a negative tilt. The 10/12Z NCEP guidance was close to the solutions they offered in previous runs, so the Canadian remained on the slower side of the guidance. The 10/12Z UKMET continued its idea from its previous run of lifting the center northeast into Kansas well before the other guidance...which seems a bit too fast. So will recommend a blend of the 10/12Z runs of the GFS and ECMWF to mitigate some minor timing differences between the two models. Note this solution ends up being fairly close to the ensemble means. The 10/12Z NAM palcement also looks fine at the end of Day 3...but the depth may end up being a tad on the weak side. ...Progressive upper trough approaching the Pacific Northwest Tuesday morning... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend Confidence: Average The 10/12Z CMC favored the slower solution to bring a surface low to the coast of British Columbia on Monday. Sensible weather impacts, though, remain north of the border. Otherwise, the deterministic and ensemble guidance shows good agreement. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Bann