Up to a foot (or more) of mountain snow in store for Rockies
Friday, September 22, 2017, 11:40 - A 'dichotomy of air masses', as the National Weather Service puts it, will exist across the nation through the end the week, with a deep trough parked over the Intermountain West and a large upper level ridge over the eastern U.S. This is what has been, and will continue to bring, below normal temperatures and snow for the higher elevations of the Rockies and Great Basin, and summer-like heat and noticeable levels of humidity from the Plains to the East Coast.
Be sure to watch the video that leads this article for full forecast details.
Below shows what the general pattern is expected to be across the U.S. through the remainder of the month.
The cool and wet pattern gripping the interior West will continue through the weekend as the upper trough stalls over the region. Temperatures are expected to consistently range between 10 degree to 16 degrees below normal through the remainder of the month.
Below shows what can roughly be expected with temperatures with respect to normal for this time of year.
FALL IS HERE: After a summer that varied from coast to coast, what can Americans expect from fall? Find out with The Weather Network’s 2017 Fall Forecast | FORECAST & MAPS HERE
An amplified upper-level trough will drift slowly east across the Great Basin and Rockies through the weekend, keeping temperatures well-below normal across the interior West (negative anomlies of 12-16 degrees F). Meanwhile, a stalled out boundary will continue to hammer the region with rain (and some embedded thunderstorms) and high elevation snow through the weekend.
The area expected to receive the heaviest amounts of snow is northern portions of Wyoming, where totals could exceed a foot by Monday (see graphic below).
Let it SNOW let it SNOW let it SNOW! 1st day of Fall or WINTER? NW continues to be flooded with below seasonal air pic.twitter.com/sag4AmbwUb— Weather Network US (@TheWeatherNetUS) September 22, 2017
Conditions will continue to be cool into the work week, before a pattern reversal evolves late this month into October.
Click play to watch below: Temperature pattern
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For lower elevations, rainfall amounts of up to 2 inches can be expected for the interior West by Monday (see below).
"With a more persistent trough setting up in the west and a high amplitude ridge in the east this will allow the jet stream to roughly park itself across the central portions of the country," says Brad Rousseau, a meteorologist at The Weather Network. "As a result, an increase in severe weather is likely across the Central High Plains as well as across the Midwest. This will likely mark what is referred to as the 'second severe weather season'".
The cool and wet conditions will bring firefighters some relief as they continue to battle several wildfires across the west. The rain could also help bring some drought relief to the northern Plains and Montana, though much more will be needed before it is entirely in the clear.