Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 1231 AM EDT Thu May 14 2020 Valid May 14/0000 UTC thru May 17/1200 UTC ...See NOUS42 KWNO (ADMSDM) for the status of the upper air ingest... 00Z Model Evaluation Including Preferences and Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Closed low over Alberta tracking to the Upper Great Lakes Thu...then across Northern New England Fri... ...Surface low moving from the north central US tonight into Northern New England Fri... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: 00Z NAM, 12Z ECMWF, 18Z GEFS, and 12Z ECENS blend Confidence: Average Shortwave energy will move from southern Alberta and northern Plains toward the Great Lakes over the next 24 hours. Through about 15.12Z, the guidance shows above average agreement aloft and at the surface, but beyond that time frame, timing differences begin to creep up. The GFS becomes a slower outlier along with the CMC. The NAM/ECMWF offer a middle ground approach with the UKMET a bit ahead of the rest of the deterministic guidance. Looking at the ensembles, the GEFS/ECENS means would also be a good approach after 15.12Z. ....Closed mid level low off the Pacific Northwest coast Thu...moving to the Northern Plains Sat... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend Confidence: Above average Model guidance confidence and agreement remains above average with the expected evolution of a closed upper level low off the Pacific Northwest coast later today that then tracks through the Northern Rockies through the end of the forecast period. A general model blend suffices. ...Mid level trough over northern Mexico Thu...moving into central TX Sat... ...Surface low over eastern NM/west TX Fri...crossing into central TX Sat... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: non-12Z ECMWF model blend Confidence: Average Longwave troughing over northern Mexico today is forecast to track eastward over New Mexico into central Texas by Saturday. Overall, model clustering has improved with the mid level feature but there remains some latitudinal spread in the feature, especially after 60 hours. The ECMWF, while an earlier northern solution, has remained consistent with some northward adjustment/trend seen in the 00Z GFS and 00Z NAM. This now solidly puts the CMC as a southern outlier and a bit outside the ensemble range. For this reason, the preferred blend removes the CMC and goes with a near equal weight of the rest available guidance. ...Low pressure developing near the Bahamas Fri night into Sat ... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: 00Z GFS/12Z ECMWF/18Z GEFS mean/12Z ECMWF mean blend Confidence: Average The 00Z GFS did not stray too far from its earlier runs and remains a consensus approach along with the 12Z ECMWF, as the area of low pressure near the FL coast gradually organizes as it moves north/northeast. The 18Z GEFS and 12Z ECENS means also remain useful with similar tracks as the deterministic runs. The 12Z CMC and 12Z UKMET remain outliers and discounted, where the CMC is considerably too far to the left/west, while the UKMET is to the right/east of the consensus. Forecast confidence remains at average to slightly above average. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Taylor