Seasonal week ahead, increasing threat for storms midweek?!

 Much of our region has experienced seasonal to slightly above normal temperatures over the past few days, this trend looks to continue as a persistent zonal flow sits over the region. A trough will sit over our region which will inhibit our temperatures from rising into the 20’s. 

Monday Night: An area of showers and weak thunderstorms are expected to rumble through the southeastern half of Manitoba , with some spotty thunderstorms in the southwestern half of Manitoba by Melita east into the Killarney regions. The cold front looks to exit the province overnight, there is a chance of a stray shower or 2 before it leaves our region. Clearing skies are expected for the evening into the overnight period. Temperatures will drop well into the high single digits, (8 to 10C) in areas of southwestern Manitoba and low teens (11 to 14C) in the southeastern Manitoba region. Winnipeg: Partly cloudy 30% chance of showers early this evening. Then clearing. Low 10C. Brandon: Clearing, low 6C. Dauphin: Clear. Low 9C. 

Tuesday: Will end up being one of the nicest days to come this week, sunny skies thanks to high pressure in the northern plains will contribute to this. There’s a good chance at seeing the 20-25C mark for a large section of the south, the only exception is the interlakes north of Teulon where highs will be in the high teens (17-20C). Manitoba lakes might manage to reach the 20C mark or slightly warmer. Winnipeg: Sunny, high 23C. Brandon: Sunny, high 22C. Dauphin: Sunny, high 21C. 

Tuesday Night: Clear skies are likely as a high pressure system to our south keeps the weather stable, alongside with a southerly flow if we were in the middle of the summer we would be talking about lows in the teens or 20’s. However because we are approaching fall even with a southerly flow in place our temperatures will not sit in the teens overnight instead they’ll be much cooler than what we are used to. Lows into the mid to high single digits are likely (6 to 10C), with the exception of the Manitoba lakes and eastern Manitoba seeing lows a degree or 2 above 10C. Winnipeg: Clear, increasing clouds before morning. Low 9C. Brandon: Clear, increasing clouds before morning. Low 6C. Dauphin: Clear, increasing clouds by morning. Low 11C. 

Wednesday: A low pressure system will be coming into Manitoba with the warm front hovering over the red river valley area by late afternoon and this will be a difficult forecast, a lot of uncertainty with the timing and impact of precipitation expected. However, it appears possibly that cloudy skies with a chance for showers will come through in the morning. However the NAM appears to be the outlier on this, the RDPS and the GDPS show a chance for mostly cloudy skies to patches of sun in areas of the south. Regardless, there will be a chance for showers in the morning. Then partly cloudy to mostly cloudy skies in the afternoon, increasing amounts of instability will be present 1000J/Kg or Joules per kilogram (amount of energy per kilogram in the atmosphere) Moisture won’t be lacking either with the dewpoints, sitting at 13C increasing to 15-16C by early evening. Also there will be adequate shear, with around 40-50knots of bulk shear, enough to support storm Organization. Once the warm front and attendant cold front come through in the evening an increasing risk for thunderstorms may occur if enough daytime heating can occur. The risk for thunderstorms will be in the red river valley and eastern Manitoba during the late afternoon. We should know more about the severity of storms possible by Tuesday evening. My best weatherman’s guess is the risk for large hail, damaging wind gusts over 90km/h because of the shear present as well as torrential rainfall. There also is a chance the best dynamics could move into Ontario. We will keep you updated. Winnipeg: Mainly cloudy, with 30% chance of showers in the morning and near noon. Becoming partly cloudy in the afternoon. 60% chance of showers with the risk of thunderstorms late in the afternoon. High 25C. Brandon: Cloudy with 30% chance of showers in the morning, then partly cloudy. High 26C. Dauphin: Mainly cloudy, with 60% chance of showers in the morning. Becoming partly cloudy in the afternoon. High 26C. 

Wednesday Night: Showers and or thunderstorms will likely occur in the early evening in the red river valley into Ontario, will probably exit the province by evening. Forecast may change if the timing of the system changes. Temperatures will of course drop into the low teens (10 to 15C) for areas of southeastern Manitoba, the parklands and the Manitoba lakes. Areas in the red river valley, southwestern Manitoba, and the interlakes will once again drop into the mid to high single digits (6 to 10C). Winnipeg: 60% chance of showers in the evening with the risk of thunderstorms, some may be severe. Clearing in the evening. Low 10C. Brandon: Partly cloudy 30% chance of showers early in the evening with the risk of a thunderstorm. Clearing in the evening. Dauphin: Partly cloudy low 13C.

Second half of the week: Sunny skies are likely on Thursday and Friday , with increasing cloud possible on Friday night. I’m also seeing a large swath of precipitation develop on Friday night into Saturday on the GDPS, the NAM hasn’t caught on to it yet. There may be a possibility that we could see a batch of thunderstorms on Friday night ahead of a warm front. Other than that our day time highs will vary from sitting in the high teens and low 20’s, (16 to 22C) with our overnight lows in the high single digits and the low teens.