Winter storm: hazardous travel, heightened flood risk and agriculture disruption ahead


"THE FORECASTS REMAIN MURKY AS THE SNOWFALL ACCUMULATIONS WILL DEPEND ON THE PRECIPITATION PHASE AND AMOUNT OF MELTING ON GROUND CONTACT (TEMPERATURES AROUND ZERO THROUGHOUT). THE LOCATION OF THE COLORADO LOW'S TROWAL, DRYSLOT, AND DEFORMATION ZONE WILL BE CRITICAL, AND LOCAL UPSLOPE FLOW AND LAKE PRECIPITATION ENHANCEMENT WILL PLAY A LARGE ROLE. THE POTENTIAL REMAINS FOR VERY HEAVY SNOW IN SOME LOCALITY IN SOUTHERN MB EXISTS, BUT IT IS TOO EARLY FOR SPECIFICS. BE PREPARED FOR IMPACTS ON TRAVEL IN SOUTHERN MB WITH THIS SNOW. IN ADDITION, THERE REMAINS A PRE-EXISTING HEIGHTENED FLOOD RISK IN SOUTHEASTERN MANITOBA, AND GENERALLY SOGGY GROUND THROUGHOUT SOUTHERN MB." - Prairie and Arctic Storm Prediction Centre


Wednesday through Saturday


Threat level: MODERATE

Impacts: HIGH (based time of year, travel impacts, public awareness, etc)

Confidence: MODERATE (based on model agreements)

Expected hazards: WINTER STORM // STRONG WINDS // BLOWING SNOW

Expected snowfall: 10-15cm

Locations impacted: extreme southeastern Manitoba // North Dakota

Expected watch: special weather statements (already issued), snowfall warnings (already issued) and/or winter storm watches (already issued)

Most likely areas impacted: Trans-Canada Highway from Steinbach, MB to Kenora, ON and possibly highway 75 from Morris to US border.

Discussion: mid-level water vapour depicts shortwave dipping into Pacific Northwest this evening with 988mb low occluding over northern Manitoba. This is placing a cold front through western Manitoba this evening. No changes to the forecast at this time, I think models today are on the aggressive side for snowfall accumulation (see below), mainly due to stalled low being forecasted. Will retain current forecast, but the >20cm in ND should be expended west and south towards Bismarck. Removed the MODERATE to HIGH impact level to all HIGH due to flooding and agricultural impacts expected, especially in North Dakota. Snowfall warnings issued for western Manitoba for higher terrain where ECCC is expecting higher localized snowfall.

Agreed with the NWS depiction (see below) of similar snowstorm as last year in October. A similar case last year was model overestimation of snowfall totals for Manitoba as well as a western shift near the event, which didn't occur. We will see how this plays out and where key features set up tomorrow.

"This week's upcoming winter storm is expected to have similar impacts to travel and agriculture compared to last year's October 10 heavy snowfall. The main difference between the two is this week's storm impacts is expected to cover a larger area impacting more people. For additional details on the October 10, 2018 storm can be found at https://www.weather.gov/fgf/2018_10_10_HeavySnow" - NWS Grand Forks, ND

...WINTER STORM WATCH NOW IN EFFECT FROM THURSDAY MORNING THROUGH SATURDAY AFTERNOON... * WHAT...Heavy snow possible. Initial snow accumulations of 5 to 10 inches possible with additional significant accumulations Friday and Saturday. Winds could gust as high as 50 mph. * WHERE...Portions of northwest Minnesota and northeast and southeast North Dakota. * WHEN...From Thursday morning through Saturday afternoon. * IMPACTS...Travel could be very difficult. Areas of blowing snow could significantly reduce visibility. Significant travel impacts are possible. Tree damage and power outages are possible. * ADDITIONAL DETAILS...There will be a very tight zone with transition from rain to snow. This will set up near Hallock, Grand Forks and Valley City. Therefore expect large snowfall differences, especially in Grand Forks county with less snow in the city and more snow west of the Air Base.

Warnings

3:25 PM CDT Tuesday 08 October 2019 Snowfall warning in effect for areas in red


A cold front pushing in from Saskatchewan will bring some rain, snow and cooler temperatures to these regions tonight and Wednesday. Most areas should expect only a few centimeters of snow accumulation with this cold front. However, cooler temperatures at the higher elevations in the Riding Mountains will lead to snowfall accumulations of 10 to 15 cm.

Travel outside of the Riding Mountains may be affected as well at times due to poor visibilities in snow and near freezing conditions. Be prepared to adjust your driving with changing road conditions. Visibility may be suddenly reduced at times in heavy snow. If visibility is reduced while driving, slow down, watch for tail lights ahead and be prepared to stop.