Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 1252 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: 00Z ECMWF/12Z ECENS mean...thru 72 hrs 12Z GFS/00Z UKMET/ECMWF blend...after 72 hrs Confidence: Slightly above average...thru 60 hours Slightly below average...after 60 hours The guidance is in good agreement through Tuesday with a deep longwave trough over the Western U.S. and a strong subtropical ridge across the Eastern U.S. going. 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. The guidance though agrees in maintaining a broad trough over the West though as additional shortwave energy drops southward down from Southwest Canada. Regarding the details, the models agree very well with the deep trough evolving over the Four Corners region through Monday and Tuesday, but there remains some very meaningful differences with the placement of the front across the Plains and Midwest, as the 12Z NAM is still displacing its front 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 00Z ECMWF has stronger support for a solution essentially in between the NAM and GFS, which is favored by the 00Z CMC/UKMET solutions and the 12Z ECENS mean. However, by Tuesday night and Wednesday, the models all agree in shifting the longwave trough east across the Plains and toward the Midwest which will allow the front to advance east toward the MS Valley and with low pressure lifting up across the upper Midwest. Regarding the surface low by Wednesday, the ECMWF ends up on the slow side of the model suite, with the GFS the fastest. The NAM and CMC cluster in between the GFS and ECMWF, but the UKMET leans toward the faster GFS. Elsewhere across the CONUS, the guidance reloads the troughing across the West by Wednesday as additional energy drops south from British Columbia. The 12Z NAM is a strong outlier as it it more amplified. The 12Z GFS is farther north with good agreement with the 00Z UKMET/ECMWF regarding this system. Based on the latest model spread and clustering of solutions across the CONUS for this period, a blend of the 00Z ECMWF and 12Z ECENS mean will be preferred through about 72 hours, with a blend of the 00Z UKMET/ECMWF thereafter. ...Tropical Depression Fourteen... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: See the latest NHC forecast advisory The guidance all agrees in taking TD Fourteen northward across the eastern Gulf of Mexico Tuesday and Tuesday night as a developing tropical cyclone with the system approaching or crossing the northeastern Gulf Coast Wednesday. The 00Z CMC takes the cyclone farthest to the left and is most progressive with forward speed. The 12Z GFS/00Z UKMET solutions next fastest and farther east with the UKMET farthest east. Meanwhile, the 00Z ECMWF and 12Z NAM are slower, but the ECMWF is more central like the GFS while the NAM is farther east UKMET. The 06Z GEFS and 00Z ECMWF ensemble means are similar to the operational runs with a central track though the 06Z GEFS mean is slower than th 12Z operational GFS. The CMC and GFS are the least aggressive in deepening the cyclone while the ECMWF NAM and UKMET are quite aggressive. Therefore, the intensity has uncertainty at this time. The 15Z NHC forecast track of TD Fourteen remains similar to that of the GFS. Please consult the latest NHC forecast advisory for more details on TD Fourteen. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Jackson