Pesky pattern to keep West cool, dreary in the coming days
Mother Nature flipped the seasons switch shortly after May began, plunging much of the western United States into a cool and dreary pattern more akin to March. AccuWeather forecasters say more of the same is on the way in the coming days, but a weather curveball late this week could usher in good news for fans of warm weather.
Places like Seattle and Portland, Oregon, had a single chilly day to welcome May, but quickly rebounded and experienced two days with high temperatures above the historical average. The warmup was short-lived as temperatures came crashing down at midweek to levels 10-15 degrees Fahrenheit below what is typical.
Farther south, Las Vegas has only had one day so far this month where the mercury soared above the historical average temperature of 84 degrees. The city hit 89 back on May 1 and hasn't been able to reach the 80s since.
Forecasters say the cool weather culprit is a persistent, pronounced southward dip in the jet stream in place over the West.
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High temperatures into the middle of the new week will remain below the historical average for places like Reno, Nevada, and San Francisco.
In addition to the persistent chill, the dip in the jet stream also left the region open to a train of smaller storms. These storms began to track through the area late in the week. Reports of between 1-2 inches of rain south of Portland on Monday evening led to flooding in some spots.
Last week on Friday alone, Seattle recorded 0.70 of an inch of rainfall. This dreary day accounted for about 37 percent of the rainfall the Emerald City typically records for the entire month of May.
Forecasters say storms and rounds of wet weather will continue to chug through the West through at least early this week.
"While most spots are unlikely to see torrential rain and should receive more intermittent showers instead, it will be enough to keep conditions dreary and abnormally cool for several days," AccuWeather Meteorologist Andrew Johnson-Levine said.
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A bit of snow may also fall as chilly air remains firmly in place.
"Given the time of year, any snow that falls will be confined to the highest mountain peaks," Johnson-Levine added. "However, this rain may accelerate the snowmelt in the Cascades and northern Rockies, which could lead to high water levels on some rivers and streams."
As the pesky pattern in the upper levels of the atmosphere begins to break down this week, warm-weather lovers should prepare to rejoice.
"An expansive area of high pressure is expected to build along the West coast late this week and continue into Mother's Day weekend, promoting drier and much warmer weather," AccuWeather Meteorologist Reneé Duff said.
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High temperatures will jump as much as 20-30 degrees in a week's time for many locations.
"This will translate to high temperatures climbing into the 80s F along the Interstate-5 corridor of the Pacific Northwest, which is about 10-15 degrees Fahrenheit above the historical average," Duff explained.
In addition, the weather is looking excellent for any planned outdoor gatherings or activities over Mother's Day weekend, Duff added.
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