Last week’s forecast quickly fell apart as two small but significant upper lows travelled across our region. The second of these upper lows moved through last Wednesday and brought with it some very cool temperatures. By Thursday morning temperatures in some localities dropped very close to the freezing point, giving us the first taste of fall. We did see the expected weak system move through on Saturday, but it wasn’t followed by cooler temperatures as warm high pressure moved in to begin the week.
This area of warm high pressure will slowly drift off to the east as the week progresses, keeping us in mainly sunny skies with warm daytime highs and cool overnight lows. Expect daytime highs to continue to be in the upper 20s, with overnight lows in the high single digits to low teens. By Thursday we will see an increase in winds from the west or southwest as an area of low pressure begins to bump up against the high. This low will bring some clouds along with the odd shower or thundershower late Friday. Things should clear out fairly quickly on Saturday as weak high pressure builds in.
The overall flow over our region for the long weekend will be out of the northwest. This will help to drop the temperatures down a bit, with daytime highs on Saturday and Sunday expected to be in the low to mid-20s and overnight lows in the 5 to 10 C range. The only fly in the ointment over the long weekend looks to be on Monday, as the weather models show a small system tracking along the international border. Confidence in this system is low, but if it does materialize, expect clouds along with the odd light shower during the day on Monday.
High pressure is then forecast to build back in next Tuesday and Wednesday, bringing a return to sunshine and light winds. Temperatures will start off on the cool side but will slowly warm up as the week progresses. Some of the weather models show a return of very warm temperatures late next week and into the weekend, but as usual, we will have to wait and see if they are correct.
Usual temperature range for this period: Highs, 17 to 27 C; lows, 5 to 14 C.