Penn State University E-Wall
The huge storm which has slammed California is what could be termed a “game-breaker” not that there is sufficient evidence that this system will create a major shift in the 500MB longwave pattern across North America.
This disturbance will take a track close to “Panhandle Hooker A” climatology, perhaps just to the west of a typical path for this kind of cyclone. This is purely a rain scenario for much of the Midwest, old South, and Eastern Seaboard. Severe thunderstorms may accompany the frontal structure over and near the middle/lower Mississippi Valley, while a miserable steady rain with drizzle and fog affects the Corn Belt and Northeast.
What makes this system interesting is its resemblance to the two other blizzards which struck the Great Plains and Midwest this season. A deepening broad trough will follow the low, sending much colder air into the Gulf Coast and eventually the Eastern Seaboard. Highs winds and lingering snows will create travel hazards from the northern High Plains through the Dakotas, northern Minnesota, and a good chunk of the Prairie Provinces into western Ontario. I expect the primary low to be replaced by secondary cyclogenesis over northern New York state by Monday, which may create a window for sleet and freezing rain in the St. Lawrence Valley and the interior of New England.
As was the case earlier in the winter, a Panhandle Hooker A cyclone will lead to colder air flooding the eastern two-thirds of the U.S. With a small but important blocking ridge in the Yukon Territory aiding the process, the deep low pressure will phase with a bitter cold motherlode moving into Hudson Bay. I doubt that the extent of the cAk domain will be much below 35 N Latitude, since the flat subtropical high centered over Haiti will minimize southward expansion of the cold. But subsequent storms and Arctic vortices will not have that problem.
Notice the very impressive equatorial moisture and energy connection near the International dateline. It is this flaring of the Madden-Julian Oscillation that will help to create a long-lived Rex signature over Alaska and British Columbia, fueling the return of a sub-Aleutian mAk vortex. So the next big disturbance to impact California and the Southwest (by January 31) is likely to take a far more southern trajectory, and a much longer period of cold weather is likely to the right of the Continental Divide.