Happy Columbus Day! Fall has been in the air over the last week or so, but it will really flex it muscles this weekend as our first big chill of the season will move into the area. Prior to the colder temperatures arriving this week will start off on the warmer side today with temps in the 70's. As we progress towards the weekend those temps will start to fall and bottom out on Saturday night. In fact, we might not see high temps get past 55 degrees for some spots on Saturday. Here is a general idea of the day by day for Northern NJ. Add a few degrees for areas south..
If we breakdown why things are going to cool down, it all comes down to the pattern of the jet stream.
Looking above I highlighted what is going on this weekend. Notice a big ridge of high pressure extending in the west all the way up into Ak. As this ridge pumps, it then allows all the cold air up in Canada to funnel south into the east. This is also aided by more high pressure near Greenland (-NAO) which sharpens the wave in the trough. In fact it just might get cold enough Saturday for snow flurries to the north!
Take a look at low temps Saturday night, many areas will get first frost..
Overall this major cool down won't last long and by early next week temps should moderate back to average. However, this will mark the true end of any lingering warm season weather.
On that note, this week I will start writing my 2016 Winter Outlook. Stay tuned the outlook will be released on Monday!