Week to End with Summer-Like Weather

Brad Leave a comment

Patience will be rewarded heading towards the end of the week as above-normal temperatures[1] are poised to return to Southern Manitoba thanks to a low pressure system that will push across the Central Prairies. In addition to the warmer weather, the chance for some wet weather, possibly even thunderstorms, will make a return as well.

Warmer air is forecast to spread eastwards across the Southern Prairies over the next 48 hours.
Warmer air is forecast to spread eastwards across the Southern Prairies over the next 48 hours.
Wednesday
14°C / 3°C
Mainly cloudy & cool; clearing in the afternoon

Today will be the coolest day of the next few as we remain on the periphery of a large pool of Arctic air. Plenty of stratus cloud will persist in Winnipeg until this afternoon; afterwards we’ll see clearing skies and a high temperatures near 14°C. Another chilly night lies ahead with temperatures dropping to the 3 or 4°C mark under continued clear skies.

Thursday
20°C / 16°C
Increasing cloudiness with a breezy southerly wind

Thursday will mark our entry into warmer weather. Gusty southerly winds will develop ahead of a warm front that will gradually push eastwards through the day. Winds will peak at around 30–40km/h with the potential for gusts to around 50km/h. Much of the day looks fairly sunny which will help temperatures climb to around 20°C by late in the afternoon, but by mid-to-late afternoon clouds will noticeably begin thicken up.

The potential for thunderstorms returns Thursday night, but it’s conditional and will be mainly confined to southwestern Manitoba. Substantial mid-level instability will couple with a strong low-level jet (LLJ) in the evening to attempt to produce thunderstorms. While many severe weather parameters output by various models look fairly impressive, there are a few concerns I have with development, somewhat related to each other:

  1. Even lifting from the low-level jet, convection looks capped. If lift is strong enough to break through the cap and taps into the mid-level instability, then strong to severe storms could be possible, but…
  2. Synoptic lift looks uncertain. While the LLJ is forecast to be quite strong at 25–35kt, deeper synoptic lift looks uncertain. Some models hint at a shortwave rippling through the region on Thursday evening, which could help initiate thunderstorms if true.
The NAM is forecasting winds in excess of 40kt at 850mb over Southern Manitoba on Thursday evening.
The NAM is forecasting winds in excess of 40kt at 850mb over Southern Manitoba on Thursday evening.

If thunderstorms did manage to initiate over southwestern Manitoba, they would have a chance of becoming severe, with the main threats being large hail and strong winds. As the system pushes eastwards overnight, the chance for showers or thunderstorms will spread into the Red River Valley. The thunderstorm potential will diminish as the system moves eastwards.

With all the cloud, potential precipitation and breezy winds moving through overnight, temperatures will remain fairly mild, only dipping down to the mid-teens.

Friday
22°C / 9°C
Chance of morning showers; afternoon clearing

Friday will continue the pleasant weather. A slight chance of showers may persist into the morning from Thursday night, but skies should quickly being to clear out, leaving us with partly cloudy to mixed skies for the remainder of the day. Daytime highs will climb into the low 20’s without too much wind to worry about.

Temperatures will drop just under 10°C on Friday night under mainly clear skies.

The Weekend Ahead

The coming weekend looks great! Mostly sunny skies will dominate through the weekend with daytime highs continuing to sit in the low 20’s and overnight lows in the mid-to-high single digits. It will be a beautiful late-September weekend, so get out and enjoy it!

  1. Normal temperatures in Winnipeg for this time in September are around 18°C for high temperatures and 6°C for low temperatures.  ↩

Near Normal Weather to Start the Week

Brad Leave a comment

The beginning of this week will feature near normal weather which will be more the result of the normal high temperature dropping as opposed to the temperature rising.

Near normal weather is expected in southern Manitoba on Monday
Near normal weather is expected in southern Manitoba on Monday

Monday

Monday
18°C / 6°C
Mainly sunny

Today will feature temperatures in the mid to upper teens, which will actually make it one of the warmer days we’ve had lately. Skies will be mainly sunny and winds will be gusty and from the west. Overall, a cool, but pleasant day.

Tuesday

Tuesday
17°C / 6°C
Mainly cloudy

Tuesday will see the return of cloudier conditions. Temperatures will not decrease significantly from Monday’s values, but the lack of sun will make it feel a bit cooler. High temperatures will remain in the mid to upper teens with light winds.

Wednesday

Wednesday
15°C / 7°C
Mainly cloudy

Mainly cloudy conditions are expected once again on Wednesday. Temperatures will will remain in the mid teens and there will be a slight chance of showers.

Long Range

The long range forecast continues to hint at the return of warmer than normal weather by late this week or next weekend. It’s too early to say for sure, but there might be one more stretch of summer weather in our future before fall really hits.

Elsewhere in Weather News: September 13th, 2014

Matthieu Leave a comment

Severe Flooding in Northern India and Pakistan

Flooding has been the story for both last weekend and this week as heavy monsoonal rains fell across northern India and Pakistan, having its strongest impact in the Kashmir, Jammu provinces and Jhang district. In this case, the heavy monsoonal rains were caused by very moist air advecting in from the Bay of Bengal due to a low pressure system located in northern India. This moist air was then lifted as it interacted with the rugged terrain of northern India and fell as heavy rain. Satellite estimates show that over 350mm fell in the hardest hit areas in a 7 day period, resulting in rivers overflowing their banks and putting residents at risk.

Satellite image of the low pressure system over northern India; combined with orographic lift, it made for heavy rain in the region. Taken on September 5th. (Source: NASA via Wunderground)
Satellite image of the low pressure system over northern India; combined with orographic lift, it made for heavy rain in the region. Taken on September 5th. (Source: NASA via Wunderground)

According to news outlets, 5,000 rescues had to be executed in the flooded region as people scrambled to higher ground. When floodwaters will have receded damages will be significant; about 980 villages in the region have seen flooding problems. On Friday night it was reported that 461 people have died due to the flooding with 600 more injured. Some 60,000 residents continue to evacuate to higher ground, not only in concern of flooding waters but also infrastructure being washed out leading to significant transportation problems for food and clean water. In developing countries the residents are typically affected by not only the initial disaster, but also the aftermath of the disaster. This is the case here as water borne diseases are of great concern to officials and will be a true threat to some residents as floodwaters recede. It’s estimated that over one million people have already been affected by this disaster.

In other news several tropical disturbances have formed in the Atlantic, including a tropical storm in the mid-Atlantic. These should be watched in the next few days, however, there is fairly strong shear in the region currently which is causing problems for these storms to develop further.

Cool Weekend, Warming Next Week

Brad Leave a comment

Cool weather will persist across Southern Manitoba this weekend as the region remains under the influence of an unseasonably cold outbreak of Arctic air. Temperatures will continue to slowly moderate, however things will be generally mixed through the weekend with a fair amount of cloud and slight chance of precipitation. The real warm-up will build into the region next week, returning us to summer-like weather.

Friday
13°C / 4°C
Mainly sunny

Saturday
14°C / 5°C
Mainly cloudy

Sunday
14°C / 5°C
Mixed skies

Today will be the nicest day that the area has seen in a while thanks to a westerly wind which will help dry out the low-levels and clear out the cloud that has been so persistent over the past week. Thanks to that, mainly sunny skies will be seen in Winnipeg and throughout much of the Red River Valley with westerly to southwesterly winds up to around 20km/h. Temperatures will remain cool, however, as the wind will be outflow from the colder air mass slumping to our south; highs through the Red River Valley will sit near the 13°C mark.

Tonight will see mainly clear skies with a little bit of cloud working in from the northwest late in the overnight period and a low near 4°C.

Cool, Mixed Weekend

Saturday will be a mainly cloudy day as a weak trough of low pressure swings through the Red River Valley. While no precipitation looks likely, there will be a slight chance of some isolated, light shower activity. The temperature will climb to around 14°C for a high temperature in the valley.

Skies will begin to clear overnight as the trough slides off into Ontario and winds back to northwesterly, although another slightly cool shot of air will be moving in behind the trough so some cloud with a chance of showers or drizzle in the lee of the lakes is likely. Lows will be near 4 or 5°C in Winnipeg & through the Red River Valley.

Sunday will bring mixed skies with a chance of drizzle or showers in the lee of the lakes. The high will once again be near 14 or 15°C while the overnight low drops to a repeat 5°C.

Warmer Weather Next Week

The NAEFS is forecasting above-normal temperatures across Southern Manitoba in the 8-14 day outlook.
The NAEFS is forecasting above-normal temperatures across Southern Manitoba in the 8–14 day outlook.

Manitobans will be repaid for their patience with the cold weather – if medium-to-long-range enesemble models are to be believed – with a hurried return to summer-like conditions. Both Canadian and American models show an upper-level ridge building eastwards across the Prairies next week brining significantly warmer air with it.

850mb temperatures will climb early next week from the –2°C or so they sit at this morning over Winnipeg to around 10°C. This warming aloft will translate to significantly warmer temperatures down here where we live, with daytime highs moving from low-to-mid teens up to the low 20’s.

The weather also looks fairly dry through the warm-up, although by week’s end there looks to be a chance of showers or thunderstorms as a low pressure complex tracks eastwards through the Prairies & Northern Plains of the United States.