Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 1210 PM EST Fri Nov 08 2019 Valid Nov 08/1200 UTC thru Nov 12/0000 UTC ..See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... ...12Z NAM/GFS Evaluation with Preliminary Preferences and Confidence... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~ ...Shortwaves cutting into the Pacific Northwest Ridge... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: 08/12Z NAM/GFS..08/00Z ECMWF blend with increasing weight to ECMWF on Monday Confidence: Slightly Below Average The latest guidance continues to show differences on the temporary breakdown of an anomalous eastern Pacific ridge through Saturday...with the models showing convergence in solutions compared to yesterday. The 08/00Z UKMET looks to be the most aggressive with a favored model blend represented by a 08/00Z ECMWF and 08/12Z NAM/GFS blend. Attention then turns downstream across the north-central CONUS as troughing advancing south from central Canada reaches the Northern Tier on Sunday. The 08/12Z GFS continued to move towards the model consensus compared to yesterday but continues to lie on the envelope of solutions for depth/strength of the 500 mb height amplification across the western High Plains and the north central U.S. from Sunday into Monday. Timing differences with a related cold front through the Great Plains show the 00Z GFS as the fastest while the 07/12Z and 08/00Z UKMET makes up the other end of the spectrum with a slower progression. Think the combination of the 08/00Z ECMWF and 08/12Z NAM appeared to be a favorable blend early on...but the NAM begins to lag in timing. The question remains whether or not to include the GFS. For the moment, think the idea of the previous shift towards including more ECMWF is still valid but will re-evaluate. ...Remainder of overall pattern across the CONUS... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend Confidence: Slightly above average A ridge-trough pattern from west to east starts off the short range period. There is flattening of the flow into Saturday evening with a fast upper level flow setting up from the Pacific Northwest into the Mid-Atlantic region. Amplification begins again by Monday morning with strong ridging along the West Coast and downstream troughing into the north-central CONUS. A general model blend should address any minor timing differences between individual models. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Bann