After a summer better called the “monsoon season” the transition into Autumn seems to have the same rain, and more rain we have seen since mid May. 2016 was the 2nd most active since 2005 with 59 thunderstorms as of Sept 8, so a few more are likely before the end of the year so I could see a tie for the most active. 2016 also made news with it’s severity being the first in a decade to see 10 or more tornadoes and was closer to pre-2002 activity, also a populated area was impacted(Ponoka) by one of these tornadoes(EF-1). I recorded a total of 16 severe thunderstorms in my single local area which is the highest number I’ve logged since i started keeping track in 2005. We are currently entering the autumn with moisture levels not seen in years so we may see thunderstorm outbreaks and heavy rainfall events into October. Unless the fall is much cooler than average 2016 will run in the top 3 warmest years on record. Much of this headroom was made during the winter which was incredibly warm.
Overall The Autumn should be near normal for temperatures and precipitation. Cooler and very wet weather in September is likely to change to a warmer and slightly drier pattern as early as Late September. With possible warm and dry periods before that. The fall could be a little of the cool and wet side for southwestern Alberta while the northwest warms up and dries out into October.
September:Slightly cooler than normal and very wet in the western part of the province, near normal temperatures and near normal- wet over the remainder of the province.
Sept 1-15: Mild and very humid for the time of year. Very wet. Some days might be reach 25C. High thunderstorm activity
Sept 15-30: Becoming drier and warmer overall. Severe thunderstorm still a likelihood.
Oct: Warmer than normal with slightly below normal rainfall/snowfall. Severe thunderstorms possible as late as thanksgiving. Unusual warmth around Halloween.
November: Closer to normal overall, drier. Very warm and drier to start the month, At some point Mid to late month strong cold and snow should move in, the onset could be very rapid.