Pattern Change To Usher In Big Temperature Changes By This Weekend

Many in the East are getting their first big taste of autumn, but that will change heading into the weekend as the pattern flips and the colder and snowier weather heads west.

The pattern in the first half of this week features a strong ridge of high pressure in the West and Plains with the jet stream nosing up into central Canada, then plunging southward across the East.

By the end of the week, high pressure will be entrenched across the East while a cut-off low-pressure system barrels through the West.

Temperatures in the East will warm from the 50s and 60s into the 70s by this weekend. A few areas near the Gulf Coast and Florida will soar back into the 80s.

By late Friday, the reversal will be complete after a bowling ball upper-level low-pressure system slides into the Four Corners region with colder temperatures and snow in some places.

(​Meteorological Mark: The Line Between Rain And Snow)

Temperatures will tumble by 20 to 30 degrees across much of the West during this transition.

For instance, Salt Lake City and Rapid City, South Dakota, will see high temperatures fall from the low 80s into the 50s in just over 48 hours. Many in the Intermountain West will see freezes this weekend.

Even Phoenix, which is about to finish its incredible run of three straight weeks of daily record high temperatures, will see lows plunge into the 50s this weekend.

Jonathan Belles has been a graphics meteorologist and writer for weather.com for 8 years and also assists in the production of videos for The Weather Channel en español. His favorite weather is tropical weather, but also enjoys covering high-impact weather and news stories and winter storms. He's a two-time graduate of Florida State University and a proud graduate of St. Petersburg College.