Monday, October 20, 2014

Nice fall weather this week

Temperatures will be running well above normal this week over southern Manitoba as an upper ridge of high pressure builds over the eastern Prairies. Sunny skies and gusty south winds Tuesday will send temperatures into the mid to upper teens, with lows 20s likely across SW Manitoba.  On Wednesday, clouds will increase ahead of a weak system crossing southern Manitoba that may trigger some scattered showers by afternoon or evening. Temperatures however will remain mild in the mid to upper teens. Sunshine will return for Thursday and Friday with temperature again in the mid to upper teens, some 10C above normal for late October.  Slightly cooler conditions are expected early next week, although there are no indications at this point of a change to a prolonged below normal temperature pattern through the end of October.     

Thursday, October 02, 2014

Big change in the weather pattern Friday into the weekend.. strong winds, colder temperatures and possible snow..

Wind and wave impact maps for south basins
of Lakes Winnipeg (right) and Manitoba (left)
Severe impacts are possible Friday Oct 3rd
along south shorelines (in red)
(image from province of Manitoba)
It was a pleasant Thursday over the Red River valley with mainly sunny skies and afternoon temperatures up to 19C. But a major change in the weather is arriving tonight in the form of a strong cold front that is pushing across western MB late this afternoon. Showers and even some isolated thunderstorms will accompany this front this evening, followed by a northwest flow of much cooler air tonight into Friday. Friday will be a much colder day, with temperatures some 10-13C colder than today along with occasional rain or drizzle and strong northwest winds gusting to 70 km/h. The rain may even mix with some wet snow over higher elevations of the western RRV Friday. Northwest winds will be especially strong over Lake Manitoba and Lake Winnipeg overnight into Friday morning with gusts to 80 km/h at times. The province of Manitoba has a issued a severe wind alert for Lake Winnipeg and Lake Manitoba warning that strong northerly winds and significant wave action may cause lake levels to rise up to 5 feet over the south basins. Note that lake levels are higher than normal due to excessive summer rainfall, especially over western MB. Lake Manitoba is at 814.2 feet while Lake Winnipeg is at 715.6 feet above sea level. The higher than normal lake levels together with strong wave and lake seiche action will lead to shoreline erosion concerns particularly along the southern and eastern shores of the lakes.

Video:  See video footage of waves at Twin Lakes on southeast shore of Lake Manitoba Friday. (from CBC)

Snowy scene Friday afternoon near Lake Brereton, MB
in the Whiteshell Park area, just one week
after experiencing 30C temperatures 
As the main precipitation shield from this system pulls away Friday, narrow bands of lake effect showers will develop over and to the south-southeast of the MB lakes. In fact, it's possible these lake effect showers may change over to snow inland from the lakes as temperatures drop Friday night into early Saturday, with the potential for accumulating snow in some narrow bands southeast of the lakes. Cold and blustery conditions will persist through the weekend with temperatures some 5-10C below normal for early October.