CLEVELAND - Keep the winter coat handy. It looks like we'll be getting cold again during the last week of October. What tells us this? Well, we need to pay attention to the weather in the Western Pacific Ocean.
Right now, there are not one, but two tropical systems off the coast of Japan. As of late Tuesday, Tropical Storm Prapiroon was centered about 300 miles southeast of Kadena Air Base, Okinawa, Japan. The storm has dropped below hurricane strength. Maximum sustained winds have weakened to 70 mph with gusts to 85 mph. The storm is moving to the west-southwest at 5 mph. Tropical Storm Maria is a little farther west. She was centered about 155 miles north of Iwo To, Japan. This system is going to accelerate to the northeast over the next few days, remaining well to the southeast of Japan.
We care about these two systems here in Ohio for one reason: The Western Pacific Recurve Rule. This rule states that when big tropical systems move north along the Japanese Coast, we can expect a surge of Cold air across Eastern Canada and the Great Lakes, and perhaps, the Northeast States in about 10 days.
The recurve rule recognizes that when tropical storms/hurricanes travel northeast out of the Western Pacific toward Alaska, a corresponding cold high pressure forms in Western Canada. This high pressure often leads to a buckling of the northern branch of the jet stream. Cold air then streams southward across Eastern Canada and the Eastern united States.
This actually happened two weeks ago when Typhoon Jelawat struck Japan and moved north. Ten days later, Ohio had its first cold spell and widespread frost event of the season.
Looking at current computer forecast (image above). This is the current EURO computer model. Notice the major cold high pressure setting up over Western Canada. That type of low pressure system is often a major cold weather producer for Northern Ohio and the Great Lakes Region by late next week. Stay tuned!