Next week residents of the upper Midwest will blanketed with a pool of unseasonably chilly air that's likely to set records across the region.
Poor man’s polar vortex to make shocking summer return in eastern U.S. next week
BY JASON SAMENOW
Bearing a haunting resemblance to January’s brutally cold weather pattern, a deep pool of cool air from the Gulf of Alaska will plunge into the Great Lakes early next week and then ooze towards the East Coast.
Of course, this is July, not January, so temperatures forecast to be roughly 10 to as much as 30 degrees below average won’t have quite the same effect.
The heart of the chilly airmass will probably just skirt the East Coast, but temperatures are likely to be about 10 degrees below normal.
One of the factors in creating this midsummer extreme weather event is
Typhoon Neoguri now unleashing its fury over Japan.
What amazes me most about the pattern is not so much the forecast temperatures, but the uncanny similarities in the weather patterns over North America seen in both the heart of winter and heart of summer. All of the same features (refer to the map at the top of this post) apparent in January are on the map in mid-July: low pressure over the Aleutians (blue shading), a large hot ridge (yellow and red shading) over the western U.S., the huge cold low or vortex over the Great Lakes (blue and green shading), and then the ridge over northeast Canada (yellow and red shading).
Map
It’s not at all clear what this means or what, if anything, it portends. Weather patterns cycling through a certain circulation regime can repeat (and we’ve seen this pattern multiple times since November-December), but with El Nino forecast to develop, the global configuration of weather systems is likely to change.