Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 103 PM EDT Sun Oct 13 2019 Valid Oct 13/1200 UTC thru Oct 17/0000 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 12Z Model Evaluation with latest Preferences and Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Deep Plains/Upper Midwest Cyclone ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend Confidence: Above average The anomalously deep layer cyclone over the north-central U.S. will continue to fill and weaken as it lifts northeast into Ontario, Canada over the next 24-36 hours. The associated cold front swept through the East Coast, but will stall/linger across the Southeast U.S. early next week and be the focus for locally heavy precipitation. A couple impulses riding along the front will enhance precipitation totals. Overall, the global deterministic model guidance is in above average agreement with the synoptic features such that a general model blend is preferred. Pacific Northwest to the Great Lakes through Tuesday ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend Confidence: Slightly above average Shortwave energy coming into the Pacific Northwest tonight will progressively cross through the Northern Rockies and into the Northern Plains through Monday Night. The trough will deepen and close off as it approaches the Great Lakes and gradually become a longwave trough over the eastern U.S. with a negative tilt. This will spawn a surface low over the Great Lakes Tuesday Night/Wednesday and also a secondary low across the Southeast U.S. that could lift toward the Northeast or New England areas by mid/late week. In the big picture, the global models are in decent agreement. By 72 to 84 hours, the ECMWF low position over the Great Lakes is ahead of the rest of the guidance, but its depiction off the East Coast is well within the model consensus spread. The 00Z UKMET is a touch slower with the 500 mb trough axis swinging through by Day 3, but it is not significant enough to exclude at this time. So, a general model blend is preferred at this time. Southwestern U.S. to southern Plains ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend (less weight given to GFS) Confidence: Average Troughing moving through the western US will eventually pinch off a southern stream shortwave across southern California early Monday. The models have come into slightly better agreement with the amplitude and axis orientation as the shortwave pushes into the Four Corners region. The GFS remains a bit ahead of the rest of the models and probably could be limited in the overall blend. The EC/ECENS mean along with the UKMET/CMC remain the most consistent and agreeable through the 3 days. Pacific Northwest by midweek ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: Deterministic model blend Confidence: Average A strong storm system originating from the Gulf of Alaska is expected to begin approaching the Pacific Northwest coast by Wednesday morning after a period of quiet weather early in the week. Although the surface cold front is forecast to pass through the region mid-week, the parent surface low is expected to remain well to the north across western Canada. There are only minor model differences with the synoptic scale features at this time, so a blend of the deterministic guidance should work well. Model trends at www.wpc.noaa.gov/html/model2.html 500 mb forecasts at www.wpc.noaa.gov/h5pref/h5pref.shtml Taylor