Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 520 PM EDT Sun Oct 07 2018 Valid Oct 07/1200 UTC thru Oct 11/0000 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 12Z NAM/GFS Model Evaluation...with Preliminary Preferences and Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Overall Pattern Across the CONUS... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: Non-12Z CMC/NAM Blend Global guidance is in good general agreement with a deep longwave trough over the Western U.S. and a strong subtropical ridge across the Eastern U.S. through Tuesday. By Wednesday, the ridge across the Eastern U.S. begins to retreat eastward allowing the height falls to eject well out across the Plains and Midwest. A broad trough is maintained over the West though as additional shortwave energy drops southward down from southwest Canada. The 12Z NAM is the most amplified with the western trough which displaces its surface front east of the Rockies south and east versus the global model consensus. The global models are well clustered with the portion of the front over the southern High Plains, but farther north there remains spread as the 12Z GFS still focuses its boundary northwest of the non-NCEP guidance along an axis from eastern CO northeast up across the upper Midwest. The other area of issue is the strength of the trough moving over the Midwest. The 12Z NAM/CMC both close off a low over the northern Plains by Wednesday evening while the remaining guidance maintains an open trough which is preferred. Therefore, the preference is for a consensus of the 12Z ECMWF/UKMET/GFS. ...Tropical Storm Michael... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: See the latest NHC forecast advisory The guidance all agrees in taking TS Michael northward across the eastern Gulf of Mexico Tuesday and Tuesday night with the system approaching or crossing the northeastern Gulf Coast Wednesday. The 12Z CMC continues to have the farthest left and fastest track with the center crossing the mouth of the MS River. The 12Z GFS and UKMET solutions are the next fastest and farther east with the UKMET farthest east. Meanwhile, the 12Z ECMWF and 12Z NAM are slower, but the ECMWF is more central like the GFS while the NAM is farther east UKMET. The 12Z GEFS/ECMWF ensemble means are similar to the operational runs with a central track though the 12Z GEFS mean is a bit slower than th 12Z operational GFS. There remains a variety of intensity with the CMC and GFS least aggressive in deepening the cyclone while the ECMWF NAM and UKMET are quite aggressive. Therefore, intensity uncertainty remains. The 21Z NHC forecast track of TS Michael is now a little to the right of the GFS by 10/18Z. Please consult the latest NHC forecast advisory for more details on TS Michael. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Jackson