Updated: Nov 5, 2020
Sunday November 8th 2020
Threat level: HIGH
Impacts: HIGH (based on population density)
Confidence: HIGH (based on model agreements)
Expected hazards: Winter storm, freezing rain, sleet, blowing snow and power outages
Expected snowfall: 15-30cm with localized amounts exceeding 30cm
Expected ice accretion:
Time frame: START: Saturday night into Sunday early morning // END: Monday morning
Locations impacted: Southern Saskatchewan // Central Manitoba
Expected watch: special weather statements then winter storm watches
Most likely areas impacted: areas of Southwestern Manitoba and Southeastern Saskatchewan
Yesterday's Discussion: did a model blend for low positioning based on last 10+ runs of ECMWF/GEFS/Canadian ensembles for above map. Fronts pulled from model blend and NWS. Low positioning quite consistent with previous model blends and early forecasts. Removed area of blizzard risk, thinking winds will not reach criteria for blizzard watches/warnings. Local whiteouts and blowing snow likely across S Saskatchewan on Sunday into Sunday night. Added transition zone N of warm front extending across Interlakes to extreme NW North Dakota. This area likely to see freezing rain and sleet on Sunday as low occludes. Transition zone should remain fairly stagnant throughout event, but may move more into Saskatchewan depending how much low occludes. Day changed for main event. Event to begin Saturday night for Prairies and peak intensity on Sunday midday. Event should end Monday morning as system departs NE across Hudson Bay. Maintained HIGH impacts and overall threat level and added HIGH confidence. This is expected to be an impactful storm.
Nov 5, 2020 Discussion: re-added blizzard area, seems wind gusts will be sustained for several hours in most of pink area to achieve blizzard warning criteria. Everything else remains O.K.
Precipitation will begin overnight Saturday across Saskatchewan and SW Manitoba. Mixed-precipitation will occur in the zones outlined above during the day Sunday and heavy snow will occur in Central Manitoba and Southern Saskatchewan. A large swath of 20-30cm is expected in the colder side of the low pressure. The transition zone will be plagued with a sharp transition between sleet, freezing rain and heavy snow. Significant ice accumulation in the 10-20mm is possible in a line from Dauphin, Weyburn to the SK/MB border and the Interlakes. Combined with wind gusting in the 50-70km/h range, power outages are very likely in the transition zone (outlined pink and orange above).
Stay tuned for watches/warnings issued by Environment Canada, which can be viewed here: https://weather.gc.ca/warnings/index_e.html