Today's the third day in a row of 70 or above for temperatures -- we'll probably eek out at least two more days above 70 in the coming week before we begin to see the temperature regime change for the cooler in the second half of October.
The current pattern is transient but mild for the Northeast and Northwest, with the coolest and stormiest weather overall presently over the Rockies and Plains. That storm system will eject northeast into Canada, with a trailing cool front moving through our region on Wednesday night into Thursday. The bigger story with this storm is that it helps set the stage for a temperature cooldown across the northern half of the country late this week and into the weekend.
Modeling in the six to ten day range is in rather strong agreement that the Great Lakes and Northeast will cool off this weekend and early next week. Details, of course, are the part that need to be fine tuned but temperatures will certainly take a dip as we work through the latter half of this week. A secondary shot of chill will pivot around the back side of this first storm, crossing the Great Lakes and Northeast on Friday and Saturday with perhaps a brief shower but a notable shift in temperatures. Parts of Minnesota, Wisconsin, and Michigan may see their first snow flakes by week's end, with our temperatures going from the 70's to perhaps the lower 60's by the time we reach Saturday or Sunday. We won't be dramatically cooler than average (mid 60's) and the coolest of cool will be in the Lakes and Midwest...but it isn't 70 degree weather.
The overall pattern that takes over brings us much closer to mid and late October normalcy -- and could provide us a few more chances at getting wet as weak storm systems shoot northeast in a fast-moving flow aloft around the trough that dominates the Great Lakes. Modeling may struggle at times to fine-tune those details as there will be a pretty robust jet stream over the top of us this weekend and early next week.
October will very likely end above normal on temperatures, perhaps top five to ten warmest, but we will see the mild regime pause later on this week and into next week as this cooler look for the Midwest and Lakes takes over.