Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 300 AM EST Wed Feb 20 2019 Valid Feb 20/0000 UTC thru Feb 23/1200 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 00Z Model Evaluation...with Final Preferences and Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Overall Pattern Across the CONUS... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend Confidence: Above average 08z update: With the rest of the 00z guidance now in, there continues to be above average forecast confidence with the models through the next 3 days across the CONUS. As such, the WPC preference for a general model blend remains the same. ---previous discussion--- Despite the active weather pattern in the next 3 days, there is above average model agreement in the large scale pattern across the CONUS. Current shortwave trough moving through the Southwest US will lift into the Plains and Great Lakes region over the next 24 hours and all the operational models seem to have a good handle on that feature's evolution. The 00z NAM continues to show some stronger amplification and also takes the surface low a bit further northwest compared to the rest of the models, but all of them are within the ensemble spread. As that low moves over the Great Lakes, a coastal low is forecast to develop off the Mid-Atlantic. The NAM has this forming the earliest, near the NC/VA border, while the GFS/ECMWF are about 6 hours later and further north. Then with the next shortwave trough digging into the southwest US and then ejecting out into Texas, there again looks to be fairly good agreement in the synoptic pattern. There seems to be minor differences in the where the low forms in the lee of the Rockies at the end of day 3. Overall, with the above average forecast confidence, the preference will remain the same for a general model blend. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Taylor