Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 235 AM EDT Wed Jul 01 2020 Valid Jul 01/0000 UTC thru Jul 04/1200 UTC ...See NOUS42 KWNO (ADMSDM) for the status of the upper air ingest... 00Z Model Evaluation Including Preferences and Forecast Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Closed low/trough exiting New England by Thursday ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend Confidence: Above average Model guidance is in excellent agreement gradually taking the upper low and associated trough axis over New England gradually off to the east-southeast over the next couple of days and ultimately offshore the East Coast. A general model blend will be preferred. Deep upper trough/closed low across the Intermountain West ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: Blend of the 00Z UKMET/ECMWF and 12Z ECENS mean Confidence: Average The upper low/trough impacting the northern Intermountain Region will advance north into southwest Canada on Wednesday as another shortwave trough drops southward over the Pacific Northwest. The phasing of this energy will keep the closed low in place over southwest Canada much of the period. However, another compact closed low and associated trough is forecast to drop south down the coast of British Columbia and into the Pacific Northwest going through Thursday. The models generally support two closed lows then by Friday with one near the Pacific Northwest and one farther north over parts of Alberta. The 00Z NAM by Friday tends to be a bit stronger with the broader height fall evolution. The 00Z CMC is still just slightly out of phase compared to the model consensus, but it has trended toward the better model clustering of the 00Z UKMET and 00Z ECMWF. The 00Z GFS now at this point is a bit out of phase with the 00Z GEFS mean and suggests stronger height falls shifting into the Pacific Northwest by the end of ther period compared to the model consensus. The 00Z GEFS and especially the 12Z ECENS mean favor the UKMET/ECMWF camp. A blend of the UKMET/ECMWF and latest ECENS mean will be preferred at this time. MCV crossing the Midwest through Wednesday ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend Confidence: Above average A convectively enhanced MCV situated along the IA/IL border, stuck in between a deep layer ridge to its south and to its north is forecast to gradually dampen and shear out over the next couple of days with some of the remnant energy digging southeastward as the ridge over the Gulf Coast states breaks down and allows a broader trough to envelope much of the Deep South and interior of the Southeast. The latest guidance generally agrees with this scenario, so a general model blend will again be preferred with this energy. Mid-level closed low over the Gulf Coast by Friday ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: Non-UKMET blend Confidence: Slightly above average Mid-level troughing and a developing closed low over the Gulf Coast states is expected by the end of the week, with weak shortwave energy dropping down from the Mid-South. There is decent agreement with the larger scale mass field evolution among the models, but the 00Z UKMET by the end of the period is notably weaker with its troughing/closed low. The 00Z GFS also may be a tad on the strong side, but there is some ensemble support for this from the latest GEFS mean, so for now a non-UKMET blend will be preferred. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Orrison