Terry’s Take: The Typhoon Rule…it’s “really” pretty cool!
A well established atmospheric connection looks like it will come into play over the next several days. Whenever a strong Typhoon nears Japan and re-curves in the Autumn, about 8-10 days later a cold snap shows up in the central and eastern United States. Wednesday’s cool-down signifies the first in a series of these fronts that will bring temperatures down to late November levels the last half of October.
This whole trend to colder weather has already been set in motion by multiple typhoons off the coast of eastern Asia. The latest storm Wipha, (once a super typhoon with 170mph winds) will make the curve and head into the Bearing Sea. The injection of heat from the storm into the upper atmosphere should enhance a “buckle” in the jet stream that will travel all the way around the globe and show up as a big dip in the jet over the eastern US. This atmospheric connection tied to re-curving typhoons off Japan is known as the “Bearing Sea rule”. The rule states that in 6-10 days the downstream effects will be progressively colder temperatures east of the Rockies and that is what we’re expecting over the next 2 weeks. You can see the chilly flow aloft on the GFS 500mb chart. You can also see temperature anomalies that are running 20-40 degrees below normal October 30th.
To make a long story short, the Typhoon rule is now in effect and it looks like a prolonged period of below normal temperatures are in our future. It’s even possible that the first snowflakes of the year will make an appearance but that’s not something I can guarantee!