Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 1104 PM EST Thu Jan 24 2019 Valid Jan 25/0000 UTC thru Jan 28/1200 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 00Z Model Evaluation...with Preferences and Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Overall Pattern across the CONUS... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend Confidence: Slightly above average Highly amplified pattern with broad global trof centered near/south of Hudson Bay and ridge directing Pacific shortwave energy well into SE AK, leads to fairly good model agreement through the next few days. As the central hub of cold air drops into Ontario/Northern Great Lakes by late Sat into Sunday, two smaller peripheral shortwaves will track across the MO Valley into Deep South/TN Valley as well a southern stream wave will emerge from NE Mexico, generally phasing across the Gulf producing a very flat, Miller-A wave signal across S Florida into the Sargasso Sea/North Atlantic by Monday, while a surface cyclone deepens across Ontario. Model spread is modest here, with typical model biases manifesting. The ECMWF and CMC are generally slower especially across the Great Lakes while a bit less phases across the Gulf leading to a slower more amplified wave north of the Bahamas, while the NAM/GFS/UKMET are slightly faster. Yet, with these differences, only start/end time differences seem to be the largest differences in QPF for a prolonged rainfall event Sat-Mon in FL. As the next, stronger shortwave drops out of NW flow, by Monday, the guidance is quite agreeable as well until about 28.00z Monday, as downstream slower solutions (ECMWF/CMC) delay eastward progression and support a further southward dive of the surface wave/cold air across the Midwest 12z Monday. Here the 00z NAM/GFS turn eastward through IA/N IL with the surface wave because the downstream wave was already north and exiting faster relatively to the ECMWF/CMC. Ensemble suite, trend, or overall weather pattern does not favor one camp/solution over another...falling more into traditional negative biases. As such a solution between the NAM/GFS and the ECMWF/CMC is preferred; and with no perfect representation in the ensemble means/deterministic guidance to be had a general model blend will be preferred but at slightly above average confidence. (please note: an arithmetic blend is NOT preferred give it will smear out the solution but a blend that recenter the wave/features toward a 50/50 position is desired). Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Gallina