Published: March 14,2017
Last week's spring-like temperatures have become a distant memory in the East, and this return back to winter will last through midweek.
A pattern change has caused a temperature shift that allowed arctic cold to return to parts of the Midwest and Northeast and is bringing warmer temperatures to the West.
This change is due to the jet stream. A southward dip in the jet stream, or upper-level trough, has developed over parts of the East. This has allowed colder temperatures and Winter Storm Stella to slide southward into portions of the Midwest and East.
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Farther west, the result is a northward bulge in the jet stream, or upper-level ridge. This upper-level ridge of high pressure will bring dry conditions to the region and above-average temperatures.
The midweek pattern behind Winter Storm Stella will feature a southward dip in the jet stream in the East, with an upper-level ridge in the West.The chilly conditions that arrived during the weekend originated in the Arctic, and this air mass brought record-cold temperatures to parts of Canada and Alaska. An all-time record low of 66 degrees Fahrenheit below zero was set on March 4 in Mould Bay, located at a latitude of 76°N and is the westernmost area of Canada's Queen Elizabeth Islands.
In Alaska last Tuesday, Fairbanks and Bettles tied daily record lows with temperatures plunging to 38 degrees below zero and 44 degrees below zero, respectively.
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This record-setting cold pushed southeastward, bringing cold temperatures to parts of the Midwest and Northeast.
Arctic Chill ReturnsCooler temperatures began to invade the northern tier last Thursday, with below-average highs stretching from Montana and North Dakota into northern Minnesota. The cold conditions pushed farther east and south on Friday and will encompass most of the Plains, Midwest and East through much of this week.
Several Northeast cities saw their coldest high temperatures on record for March 11 on Saturday, including Bangor, Maine (13 degrees), Providence, Rhode Island (23 degrees), and Watertown, New York (17 degrees).
Sunday morning, Portland, Maine, set a new daily record low for March 12 of 1 degree, while Boston (9 degrees) and Providence, Rhode Island (11 degrees), both came very close to their daily records.
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The below-average temperatures will last into midweek as another surge of much-colder-than-average temperatures arrives behind Winter Storm Stella, leading to temperatures plunging into the 20s in portions of the Southeast.
Lows could drop below freezing as far south as north Florida, including Jacksonville, Thursday morning, with 20s stretching into Atlanta, Nashville and Charlotte, North Carolina.
Forecast Morning Lows
This blast of cold and below-freezing temperatures is bad news for areas where leaves and flowers are already blooming and there are agricultural concerns, especially in the Southeast midweek. The expected hard freeze could cause serious damage to fruit trees in the region.
Temperatures will begin to moderate in the Plains and parts of the Midwest by Thursday and for much of the East by the weekend.
Southwest Heats UpAfter a wetter-than-average winter, much of the West will experience a dry stretch of weather this week, with the exception of the Pacific Northwest. Along with the dry conditions, warmer temperatures are expected to take hold of the Southwest, California, the Great Basin and much of the Rockies.
These conditions are due to a strong area of high pressure that will dominate the Southwest, pushing temperatures well above average.
Five Day Forecast
Temperatures will climb into the 80s and 90s in portions of Southern California into the Desert Southwest, while 60s and 70s are expected as far north as Denver, Salt Lake City and Boise, Idaho.
Death Valley, California, set a new daily record high of 98 degrees on Sunday, while Las Vegas tied its daily record high of 86 degrees.
Monday, Phoenix tied its daily record high of 92 degrees, which was the first 90-degree temperature of the year there. This was earlier than average, as the average date for first 90-degree day is March 31.
Record-high temperatures were set in Flagstaff and Prescott, Arizona, Tuesday afternoon, with highs of 71 degrees and 80 degrees, respectively.
Several more record highs are possible this week, including (current record in parentheses):
- Wednesday: Phoenix (92 degrees); Las Vegas (87 degrees); Albuquerque, New Mexico (77 degrees); Colorado Springs, Colorado (74 degrees); Salt Lake City (73 degrees); and Grand Junction, Colorado (72 degrees)
(MAPS: 10-Day Forecast)
Tucson, Arizona, saw its first 90-degree high on Friday, which is earlier than the average of April 4. Los Angeles finally reached 85 degrees this year last Wednesday, as the average date of first 85-degree day is Feb. 14.
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