The month of September started off as a dry, and somewhat mild month as our temperatures were near 90 on the first day of the month. Somewhat cooler, yet dry weather, continued from the early part of the month through about the mid-way point until "whammo", here comes a "cut off low pressure system".
You may be asking, what exactly is this and what does it mean? Well, have a quick read below and get caught up on it. :)
Cut off low pressure systems happen when they develop in either extremely weak upper level wind conditions (jet stream, around 40,000 feet in the air) or away from the jet stream altogether (most common). Without some kind of steering mechanism, such as the wind from the jet stream, they basically just drift from day to day with little, if any movement. This is exactly what happened from September 20 through September 27, which is why we had so much cloud cover and occasional rain during this time. In addition, factors such as a northeast wind, thick cloud cover and rain, pushed temperatures well below normal with most highs getting stuck in the 40's on September 22, the day before fall started.
You can view this animating by visiting:
Designed by Gray Digital Media