Tuesday, July 25, 2017

Seasonably warm weather to close out July.. but 30C heat continues to elude Winnipeg

It will be a nice warm week ahead with high temperatures generally in the mid to upper 20s over the RRV and southern MB. Conditions should be generally dry as well with little in the way of showers or thunderstorms expected through Friday. The next threat for organized showers will be on Saturday as a weak frontal system slides through southern MB. The greatest heat through the end of the month however will still be focused out west over SK and AB which have experienced multiple days of 30C or more this month. In Winnipeg, we have yet to hit the 30C mark in July, even though precipitation has been below average and sunshine has been plentiful. The upper pattern this month has brought the bulk of the heat over western Canada with cooler temperatures over eastern Manitoba into Ontario.  There is a chance Winnipeg may be close to the 30C mark by the end of the week. Since 1872, there have been 12 Julys in Winnipeg that have failed to reach the 30C mark, most recently in 2009. With one week to go, we'll see if July 2017 is added to that list.

Saturday, July 01, 2017

Coolish Canada Day 150.. but then heat builds for first half of July over Prairies

Happy Canada Day!  Canada is 150 years old today, founded back on July 1st 1867, and celebrations marking the milestone event will be held throughout the country. In southern MB, skies on Canada Day will likely start off cloudy as a disturbance tracks across southwest MB into North Dakota tonight into Saturday. This system will spread a few showers across SW Manitoba tonight and into the Red River valley overnight into Saturday morning. The bulk of showers will likely be mainly south of Winnipeg, but there is the chance the city may see some showers Saturday morning. The system should be out of southern MB by midday leaving a mix of sun and cloud Saturday afternoon along with a northerly breeze of 20 km/h. Temperatures will be on the cool side of normal with highs around 21C, a few degrees shy of the average of 25C for July 1st, but quite comfortable for outdoor activities. There is the chance of some isolated showers popping up Saturday afternoon with daytime heating, but most areas should be rainfree for Canada Day festivities. Skies will be clearing by Saturday evening, with ideal conditions for fireworks at 11 pm.. although a little on the cool side with temperatures near 15C by that time. The rest of the holiday weekend is looking good with sunshine on Sunday and highs of 24C and 27C by Monday under partly sunny skies and increasing southerly winds.  

Pattern change will bring increasing heat over western Canada and Prairies first half of July


Large upper ridge building over western Canada next week
will bring increasing heat over the Prairies, especially west
850 mb temperature anomaly shows core of heat next week
will be over western Canada with highs of 30-35C
A pattern change is expected for the first half of July over western Canada and across the Prairies as a large upper ridge builds over the High Plains and Rockies. This will bring increasing heat over much of the Prairies over the next 1-2 weeks, with a prolonged heat wave possible over Montana, southern AB, and SW Saskatchewan with highs in the mid 30s to possibly 40C in some localities. Look for widespread heat warnings to be issued for much of Alberta and Saskatchewan early next week. Here in southern MB, temperatures won't be quite as hot as out west, but they will climb to above normal values with highs in the upper 20s to low 30s this week, with mid 30s possible near the SK and North Dakota borders. There may be a day or two with thunderstorms as weak fronts pass through southern MB, but overall precipitation is expected to average below normal for the first half of July over much of the Prairies. There is a chance that the upper ridge may build east into southern MB by the second week of July which would bring more intense heat here as well (highs of 35-38C). However, that is still a ways off and we'll have to see how models handle the upper ridge pattern in the days ahead. Regardless, get ready for an extended period of hotter temperatures over the next week or two.. as we get into the climatologically warmest part of the year in southern MB.    
                  

Sunday, June 18, 2017

June to end on a cool note..



Temperature outlooks from CPC show favour below normal temperatures
across the Prairies for the next 1-2 weeks at least 

After a nice warm first half of June, the weather pattern has shifted over the Prairies this past week, with the warmest air now suppressed south of the international border. The jet stream has shifted south allowing cooler air from the north to move across the Prairies. And it looks like this pattern will likely persist for the rest of the month into early July. Tomorrow and Tuesday should see a mix of sun and cloud with highs of 18-21C, then a system passing through southern MB will likely bring some showers and thunderstorms Wednesday with highs in the low 20s. Cooler temps will follow for the end of the week, with below normal temps in the teens and scattered showers likely next weekend.  A return to sustained heat in southern MB isn't expected before early July.

Monday, May 29, 2017

Warming trend this week.. dry weather expected into next week

It's been a cool and wet couple of days over southern  Manitoba, but things will be clearing up nicely this week as a stubborn area of low pressure over northern Ontario finally pushes east allowing high pressure to build in from the west. Cloudy skies Tuesday will give way to increasing sunshine by afternoon as the high pressure ridge moves in from Saskatchewan. This will lead to some glorious weather through mid week with plenty of sunshine and temperature in the mid 20s Wednesday and Thursday. The warmer weather will retreat a bit on Friday and Saturday with highs around 20C as we get easterly outflow winds from a cooler high pressure system moving across northern MB into NW Ontario. But things should warm up again by Sunday into next week as we get a return flow of warmer air back into southern MB.

As far as precipitation goes, it looks generally dry through the first week of June with long range guidance showing little in the way of major systems or convection over much of southern MB through the next 7-10 days. There is a risk of some showers and thunderstorms over SW MB Friday, but the risk appears restricted to SW MB into North Dakota. Things are actually getting a bit dry over southern MB, especially over far SW MB which has received only 10-20% of normal rainfall so far this month. Even the RRV has only seen about half the usual rainfall in May (normal May precip is about 55-60 mm) Farmers will be getting increasingly anxious if the dry weather continues for much longer as it will start to affect their newly planted crop.

Sunday, April 23, 2017

Oh no! More snow!

It will be back to winter like weather over southern Manitoba Monday as a storm system intensifies over the Dakotas and tracks into northern Minnesota by Monday night. A band of snow is expected to spread into the Winnipeg area by mid morning Monday, with snow intensifying through midday into the afternoon before tapering off Monday evening. Snowfall accumulations will be tricky as some of the snow will be melting on impact, and there will be milder air over southeast MB that will change snow to rain for awhile over parts of southeast MB. For Winnipeg, precipitation should remain as snow with a good 5-10 cm expected by late afternoon, and perhaps 10-13 cm by the time it ends Monday evening if we get under some heavier bands. The best bet for heaviest snow will be towards the Ontario border where 10-20 cm is possible Monday into Monday night.    

UPDATE:  (9:30 am Monday): Latest guidance and radar indicating Winnipeg will be on western edge of this system with bulk of snow mainly east and southeast of the city. Winnipeg will likely still see some wet snow by late morning into this afternoon, but amounts should be minimal with perhaps 2 cm or less on grassy surfaces. Roads will just be wet. Wet snow may even mix with rain here at times today as temperatures stay above freezing. Heavier snow will be confined just to the east and southeast of Winnipeg in places like Steinbach, Whiteshell and Falcon Lake where 5-15 cm of snow is possible through this evening.  

How unusual is heavy snow in late April? 

Although not common, snowstorms are certainly not unheard of in late April or even May in Winnipeg and the Red River valley. Consider these top 10 late season snowfalls (daily) that have occurred in Winnipeg after April 15th. As the table shows, heavy snowfalls have occurred in Winnipeg well into the 3rd week of May.

TOP 10 LARGEST DAILY SNOWFALLS AFTER APRIL 15  
              (WINNIPEG DATA 1872 - 2016)

1.  29.0 cm ............ May 11 2004
2.  21.1 cm ............ May 1 1967
3.  20.8 cm ............ Apr 27 1966
4.  20.3 cm ............ May 19 1931
5.  20.0 cm ............ May 9 2002
6.  17.3 cm ............ Apr 24 1937
7.  16.5 cm ............ Apr 25 1960
8.  15.2 cm ............ May 20 1882
9.  14.0 cm ............ Apr 19 1996
10. 13.0 cm ........... May 5 1938

In 1958, a full fledged blizzard hit Winnipeg on April 28th with 5-10 cm of snow blown by 80-100 km/h winds along with frigid temperatures of -10 to -13C.