How a typhoon so many miles away can create impacts in weather across North America….

It may seem hard to believe, but Typhoon Bolaven, now caught up in the westerlies and tracking well east of Japan, could be a major influence on weather in the medium range and longer term. Bolaven will merge with a formative cold vortex below the Aleutian Islands. That system, in turn, will spread warm advection aloft across the western half of the continent. As the combinant disturbance becomes anchored over the western Gulf of Alaska, the stable warmth and ridging will spread above the Arctic Circle form AK through northern Canada and Greenland.

All of that ridging will act to keep the mean storm track suppressed into the lower 48 states. While the current cyclone spreads its thunderstorms and rain shield into the East Coast this weekend, the next such feature will have higher impacts in regard to heavy precipitation in Appalachia and the Mid-Atlantic during the medium range. October 21 – 23 could see strong winds in the Ohio Valley, Great Lakes, and Northeast as this system deepens and slows down under a -NAO styled blocking signature.

I suspect that this will form the basic template for national weather after Thanksgiving. Much of November is bound to be mild as the atmosphere relaxes and “takes a break”. But other tropical cyclones in the western Pacific Basin seem likely with an increasingly Modoki-oriented El Nino (warmest equatorial waters sectors 4 and 3.4). It is too early to tell the particulars. But my suspicion is that with the ridges at high latitudes and not in a lateral display across southern Canada, cold air will start to expand its presence in the lower 48 states.

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