Thursday, 7 June 2012

Severe Weather

Photo credit   CBC
     It's going to be a bumpy ride in southern Manitoba over the next several days. Thunderstorms are possible everyday from today through to Sunday.
     Today is a hot and humid day in southern Manitoba, with highs near 30°C in the city of Winnipeg and humidex values in the mid thirties. This along with a cold front near the Saskatchewan border and high instability is providing the risk for some strong storms in southwestern Manitoba this afternoon. These storms will have the potential to be severe with the main threats being large hail, damaging winds, excessive rainfall due to the slow motion of the storms and even a small risk of an isolated tornado.
     Rains and storms moving north from North Dakota this evening and overnight will be bringing significant rainfall from the US Border up to the Swan River area. Locally up to 75 mm of rain will be possible in the Riding Mountains area from now to tomorrow morning. As a result of this potential, Environment Canada has issued a rainfall warning in some areas, calling for 40 to 70 mm of rain:
Rainfall warning for tonight. 40 to 70 mm possible.
     These rains and storms will move into the Interlake and eastern areas of Manitoba tomorrow, giving up to 40 mm in areas such as Fisher Branch and Bissett.
     Here in the RRV and southeastern Manitoba, you could say we will likely miss the worst of the storms, however the potential is still there. The best chance will be later in the evening and overnight. Locally heavy rain will be possible, however storms should remain non-severe in this area. A good light show is not out of the question.
     Lingering showers and storms are still possible in the morning and to start the afternoon, before things begin to clear later in the afternoon and evening Friday.

     The real action is Saturday. Uncertainty still exists, so it is recommended you stay tuned for updates as Saturday could feature the first significant severe weather outbreak of the year. High shear is possible Saturday which brings in some concern about the potential for tornadic activity in northern North Dakota and in southern Manitoba. Due to very high instability and moisture, very large hail will be possible as well. SPC in the US has us in a hatched risk already for Saturday, which signifies a 10% + probability of significant severe weather within 25 miles of a point. This risk could be upgraded in the future if needed.
     Sunday is even more uncertain at this point, therefore I wont say much about that day. Some models bring in the potential for more storms, while others don't. Stay tuned..

     A cool down will take place behind this system for next week. Highs in the high teens look possible, which will be quite different from what we've gotten used to the past week.

     A list of things you can do to prepare for a severe weather outbreak here.


  1. Cloud stuck around longer than expected so our highs today were a lot lower than they could have been. Instead of 25 or 26°C, looks like we'll top out at 21 or 22 instead.

  2. Models are finally coming into agreement as of the 00Z runs this evening. The NAM has pretty much completely reversed, now going with pretty much all the other models now.

    That being said, that means the best chance for tornadoes and supercells will be in south/southwest Manitoba, likely west of Winnipeg tomorrow late afternoon and early evening. The storms would likely move east, and possibly evolve into an MCS for southeastern Manitoba later in the evening and overngiht with the potential for significant rain, and possibly large hail and damaging winds.