If you’re heading to Denver Labor Day weekend into early next week, great luck packing. You’ll desire shorts, sun block, flip flops, a hat, gloves and a winter season jacket. Get ready for three seasons in 3 days.
The holiday weekend looks downright hot, with highs in the mid- to upper 90 s in the majority of places throughout the Colorado Front Range. On Labor Day itself, temperatures need to hover near 90– before crashing into the 30 s by Tuesday afternoon or night.
For some, building up snow is possible Tuesday into Wednesday, just a week into September.
A temperature change of 60 degrees in 36 hours is possible, the heat of summertime suddenly generating a flash winter.
” This will be an interesting potential weather event,” said David Barjenbruch, a meteorologist at the National Weather condition Service office in Stone. “Monday we could be 100 in a couple of areas. We might go from record hot to near-record cold.”
The abrupt seasonal turnaround would be severe practically anywhere else, but in Denver, strong cold fronts aren’t extremely uncommon. On October 9, 2019, Denver struck a high of 83 degrees. Eight hours later on, it was snowing.
Temperature levels that day dropped some 40 degrees in four hours, the meteorological caprice wrangling both a record high and low for the date.
In Denver, Sunday is forecasted to approach the century mark, with lower 90 s on Monday. Tuesday might peak in the lower 50 s before toppling into the 30 s. Some accumulating snow can not be dismissed during Tuesday’s second half.
To the northwest in Stone, highs near 90 are likely on Monday, with over night showers and thunderstorms along the cold front. Tuesday will feel like late fall or winter season, with temperature levels ultimately falling below freezing and even a greater chance of snow than Denver.
In Cheyenne, Wyo., the shift might be squeezed totally into Labor Day, with highs in the 80 s and lows near freezing.
” Cold Arctic airmass in the wake of the low will turn the location thermostat down rather substantially with record low temperatures possible Wednesday morning and extensive frost possible,” composed the National Weather Service in Cheyenne.
Temperatures Wednesday early morning in Cheyenne might drop into the teenagers.
High Plains temperature level magic
The terrain of the High Plains and Front Variety is the secret to its temperature swings. Fixed fronts can get caught up in the mountains, causing big temperature level modifications over very little distances. Other times, the forcing of air up or down slopes can compress or broaden pockets of air, their temperature levels warming or cooling, respectively.
” Right along the front variety, one main reason is that, before the front can be found in, you get downslope warming and compressional heating,” stated Barjenbruch. Downsloping, which happens when air moves down a hill or mountain, can lead to warming as its atmospheric pressure increases near the earth’s surface. For every single 1,000 feet a pocket of air sinks, it warms 5.5 degrees Fahrenheit.
” Then we switch to this big upslope and cooling … it’s a double whammy,” Barjenbruch stated. “There’s very little small amounts with these air masses. That’s the huge distinction from something that moves into the eastern U.S.”
The start of fall in the High Plains
The modification of the seasons doesn’t come like a progressive downhill slope in Denver; it’s more like being lowered a flight of stairs. In a lot of years, the greatest cold fronts come between October and December, though it’s not unusual to see them as early as September.
” It’s typically early to mid-September we’ll have our very first strong cold front move through for the season,” Barjenbruch said. “But this one is really packing a big punch.”
An analysis of same-day temperature level variations in Denver shows that temperature swings in September and October are typical, in addition to in the spring as the seasons shift.
The best calendar day temperature change in Denver came on January 25, 1872, when an early morning high of 46 degrees crashed to minus-20 at night.
It’s not uncommon for the Denver area to have a 40- plus degree temperature level change throughout it as the winds modification and scour out one air mass for another.
” Components of west side of Denver may be 60 degrees with downslope warming, yet the east side of Denver might be 10 or 20 degrees,” stated Barjenbruch, referring to air that puts down the lip of the Rockies and warms. “We call that the Chinook wind.”
Pacific tropical cyclones playing a function?
As crazy as it may sound, part of the meteorological roller coaster over the High Plains can be partially traced back to a set of tropical storms in the northwest Pacific.
As the tropical cyclones, named Maysak and Haishen, move northward to the midlatitudes, they modify and supercharge the jet stream by hitting it. That affects locations downstream, realigning where the crests and troughs in the serpentine river of air end up being established. Warm air southern builds in underneath the ridges, while the troughs are inhabited by cool air and storminess.
Image the ripples that form downwind of a stone in a river. If you move that stone or include another atop it, the shape and position of those downstream ripples changes accordingly.
Whatever lies in shop early next week is bound to keep Coloradans on their toes.
Wild temperature level swings of the past decade in Denver
- Feb. 24, 2014: In two hours, the temperature leapt from 26 degrees to 57 degrees in the midafternoon. The temperature remained at 63 degrees up until 10: 30 p.m. By midnight, it had actually fallen to 29.
- Jan. 5, 2015: 27.9- degree jump, from 12 degrees to almost 40 degrees in one hour. The same day featured a 15- degree drop in one hour, thanks to a stalled stationary front. After a morning low of minus-4, the thermometer stood at 55 degrees right before midnight, marking the biggest one-day temperature swing of past years. Wednesday’s cold front simply fizzled.
- Dec. 9, 2016: 11 degrees at 3 p.m., 53 degrees at 8 p.m.
- Dec. 27, 2017: 2 degrees at 2 p.m., 45 degrees by 6 p.m. 2 days later, on Dec. 29, the temperature level swung from 63 at 8 p.m. to 30 degrees by midnight. The next early morning’s low was 9 degrees.
- October 9-10, 2019: 82 degrees at 3 p.m., 32 degrees at 10 p.m. Winds gusted to 55 miles per hour as the cold front rushed through, with snow falling shortly thereafter.
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