As we begin our full transition into the fall season we are starting to notice this rather constant swing of temperatures ranging from 80s early on to highs in the 60s, then going back up again. This is primarily due to the average position of the jet stream. Without going into nitty gritty detail, think of the jet stream as a rough divider between cooler and warmer air. With that, the jet stream will kink due to differences in temperatures. This will cause areas of low and high pressure to form at the surface giving us our weather.
Normally, during the summer months the Northern Hemisphere is warmer, and allows the polar jet to settle further North.
Inversely, during the winter the Northern Hemisphere is cooler and pushes the jet stream further South. So, when we reach the summer or winter we don’t usually see dramatic 20º+ high temperatures very often. This is because the jet stream is further North or South depending on the season. Keeping highs more consistent. During the fall and spring seasons the jet stream starts to move, which just so happens to be very close to overtop of us.
Right now it is slowly making progress to the south, allowing cooler air to settle in more frequently. Because the average position of the jet stream is closer to overtop of us, we are also subject to more frequent temperature swings like we’ve been seeing.
This past week was an excellent example of that as we were in the 80s last weekend, then the 60s by mid week and now were back in the 70s again.
With all of that in mind, we are going to continue to see this up and down trend over the coming weeks. So, lets take a closer look at this week.
Over the past week we saw our highs fall from the 80s to the 60s, but we are on an upward trend.
Monday through Tuesday we are looking to return to the 70s again with lots of sunshine. Quite nice, but seasonably well above normal. Here comes the swing again.
By Wednesday we can expect another kink in the jet stream to bring a surface low pressure system. This will inherently bring out next rain chances and cool us back down again.
Going forward in time, after Wednesday our temperatures fall back to the lower 60s and stay near normal for a bit.
Much like clockwork, we will likely see another swing back up to the upper 60s and lower 70s again by the start of next week.