Monday, January 12, 2015

A break in the deep freeze this week..

Temperatures will be on the rise this week over southern Manitoba as the upper weather pattern allows a milder Pacific airmass to spread eastward across the Prairies.  As a result, the minus 20s and minus 30s of the past two weeks will give way to more moderate temperatures, likely reaching -5C or higher by Thursday.  In the meantime, we have another cold night ahead with temperatures remaining steady near -23C tonight with southerly winds of 30 km/h giving windchills in the mid -30s into early Tuesday morning. Temperatures Tuesday will finally be edging upward with temperatures near minus 12C by evening, although the day will see brisk southerly winds of 30 km/h or more through midday before easing by evening. Wednesday will see a clipper system tracking through central Manitoba bringing a band of snow mainly through the Interlake regions, although Winnipeg will likely see a band of snow through midday of perhaps 1-2 cm. Note that the snow will be accompanied by gusty south winds to 50 or 60 km/h, so reduced visibilities in snow and blowing snow will be an issue in the RRV as the band of snow moves through. Behind the snow, winds will shift into the west as the clipper tracks east, allowing milder temperatures over southern Saskatchewan to spread into southern Manitoba by afternoon and evening. Look for temperatures to rise to -3C or so in Winnipeg Wednesday night as southerly winds shift into the west.  After a mild start, Thursday will see slightly cooler conditions move in (but still above normal) as we get "backdoored" by a cool front thanks to NE outflow winds from a colder high pressure area over northern Manitoba. This will be followed by another surge of milder air over the weekend, possibly preceded by another band of snow Friday.  All in all, a change to milder weather on the way this week, but a bit of a roller coaster ride as periodic clipper systems move across the Prairies.

Thursday, January 01, 2015

A snowy start to 2015

24 hr snowfall estimates from WPC ensemble (inches)
to midday Saturday. Heaviest snow expected
mainly south of Winnipeg through Friday night
December finished with well below normal snowfall in Winnipeg with only 7.2 cm of snow recorded during the month (as observed by the Charleswood climate station)  This would rank as the 16th least snowy December in Winnipeg since records began in 1872.  Snowlovers have been anxious for some significant snow to fall across southern Manitoba as weather systems have been few and far between so far this winter season. But it looks like our first significant snowfall since late November is on its way across southern MB as a fairly intense clipper system tracks across southern SK into North Dakota Friday into Saturday. Snow from this system will spread across southwest MB Friday afternoon and into Winnipeg/RRV by Friday evening. Snow will be falling moderate to heavily Friday night with snowfall rates of 1-2 cm/hr at times before tapering off Saturday morning. At this point, it looks like the system will be bringing a wide swath of 10-20 cm of snow along and south of the TransCanada highway, with the heaviest amounts over southwest MB through the southern RRV into SE MB. For Winnipeg, it looks like we'll be seeing around 10 cm of snow Friday night with lesser amounts to the north of the city, and higher amounts to the south. In addition, northerly winds will be increasing overnight into Saturday morning giving areas of blowing and drifting snow especially outside the Perimeter and into the southern RRV. As a result, expect poor driving conditions Friday night into Saturday across the Red River valley into North Dakota and Minnesota. (NWS has posted winter storm watches and warnings for northern ND and northern MN due to this system)    

Sunday, December 21, 2014

Staying mild until Christmas.. then pattern change to colder weather

Today may be the official start of winter, but the unseasonably mild weather of the past two weeks is forecast to continue for the the next few days with temperatures some 10-20C above normal for late December.  Highs today and Monday will be near or slightly above freezing with nighttime lows only around -2C, well above normal highs of -11C and lows of -22C for this time of year.  The weather will continue to be generally cloudy and dull with a chance of freezing drizzle or light flurries from time to time today into Monday. A storm system tracking into the Dakotas Monday into Tuesday will bring some light snow across the Red River valley and SE Manitoba, with a couple cm possible, especially south and east of Winnipeg. Cloudy and slight cooler conditions are expected behind this system for Wednesday into Thursday (Christmas Eve and Christmas Day) although temperatures will continue above normal, with highs near -5C. A storm system tracking though the Dakotas Thursday night into Boxing Day may bring a round of snow to southern Manitoba, but the main story with this system will be the colder air that will follow in its wake. Temperatures are expected to drop to normal or below normal values for Boxing Day and the weekend into next week, with temperatures in the minus 20s and possibly minus 30s again.

Thursday, December 04, 2014

Major warm-up expected across Prairies, much of North America next week..

6-10 day outlook valid Dec 10-14
showing massive warmup over
central North America (CPC)
For those already tired of the mid winter-like cold that has gripped southern MB and the Prairies much of the past 3 weeks, some good news is on the way. A major shift in the weather pattern next week is expected to bring a prolonged period of above normal temperatures across much of the southern Prairies and central North America through next week. We'll get a taste of the milder weather on Sunday as a weather system tracks across southern Manitoba bringing a southerly flow of milder air across the south, with temperatures likely climbing towards the freezing mark in Winnipeg and slightly above freezing over parts of western MB. We'll get into some briefly colder air on Monday behind this system, but the colder weather will be short lived as a massive influx of Pacific air spreads over the Prairies beginning Tuesday. This flow of warmer Pacific air will overspread southern Manitoba by mid to late week, sending temperatures in Winnipeg and the RRV above freezing from at least Thursday into Saturday. In fact, some downslope areas from Dauphin through McCreary to Portage La Prairie, Morden and Winkler may see temperatures of +7-10C by Friday.  That will result in considerable melting of the meager snowpack across southern Manitoba.. with areas of  bare ground likely re-appearing by the end of the week in parts of the RRV and SW Manitoba. So put away the block heater cords for awhile and stock up on the washer fluid.. warmer weather is on the way!

Friday, November 28, 2014

5-10 cm of snow on the way for Winnipeg

24 hr precip amounts in mm to noon Saturday
(add 50% for snowfall amounts in cm) 
Get those shovels ready.. snow is on the way across much of southern Manitoba today into tonight as a storm system over Montana tracks into the Dakotas. Snow from this system has spread into western Manitoba this morning and will continue to spread eastward into Winnipeg and the Red River valley this afternoon. Snow will pick up in intensity by the afternoon rush hour, with 2 cm possible by evening. Snow will continue tonight into Saturday morning with another 5 cm possible in Winnipeg by the time it tapers off by midday Saturday. In total, about 5-10 cm of snow is possible across Winnipeg and the northern RRV, with less to the south of Winnipeg and more to the north. Heaviest snowfall for this system is expected over western MB Parklands and central Interlake regions (Riding Mtns, Dauphin, Arborg, Ashern, etc) where 15-20 cm is forecast by Saturday. In behind this system, winds will shift into the northwest Saturday tapping cold Arctic air once again, with temperatures falling from morning values of -10C towards -20C by Saturday evening. Cold but dry weather is on tap for Sunday and Monday with a moderating trend the rest of the week as the arctic airmass relaxes its grip over southern MB.