Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 316 AM EST Wed Nov 27 2019 Valid Nov 27/0000 UTC thru Nov 30/1200 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 00Z Model Evaluation with Preferences and Forecast Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Overall Pattern Across the CONUS... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend Confidence: Slightly above average 08Z update: Through 60 hours, the 00Z model guidance did not significant deviate from early 00Z guidance and model trends. The most notable differences occur at the end of Day 3 with the next storm system poised to eject out into the central Plains. The GFS now looks somewhat of an outlier with its far northwest surface low position at 84 hours compared to the rest of the guidance. The UKMET trended a bit toward the CMC (southeast solution). For now, will keep a general model blend preference but the 00Z GFS may need less weight if trends continue. Fairly amplified and anomalous synoptic pattern evolving over the CONUS the next 3 days leads to fairly good agreement with the latest model guidance. The initial closed, negative tilted low over the Plains will quickly move through the Great Lakes and off the Northeast U.S. coast by Thursday. In response, a much stronger longwave trough will encompass the western U.S. with some ridging downstream. By the end of Day 3 /Saturday/ pieces of that energy will eject out into the central Plains and lead to another strong surface low. Overall, the 500 mb pattern is well agreed upon with little spread seen in the global deterministic guidance. At the surface, there is tight clustering with the two current storm systems. By Saturday, as the next low develops across the central Plains, there is some latitudinal spread where the GFS is the furthest northwest (southwest SD) compared to the CMC (east-central NE). A general model blend would likely yield a sufficient solution now, where the ECMWF/UKMET seem to be a good proxy for at this time. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Taylor