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An incredible temperature contrast across
the state of Texas on April 9, 2013. |
While snowstorms in April are not uncommon the latest winter storm that hit the week of April 7th, 2013 certainly produced its share of odd weather.
The driving distance from Dalhart, Texas, in the northern Texas Panhandle, to Laredo along the Rio Grande River, is roughly 750 miles, or just over 11 hours.
That said, an incredible temperature contrast set up on April 9.
Just before midnight, Dalhart bottomed out at 22 degrees behind a plunging cold front. For perspective, the all-time April record low, there, is 17 degrees.
In Laredo, the daytime high was 108 degrees. Last year, Laredo didn't warm to 108 degrees or warmer until June 10.
That makes an 86 degree temperature contrast across the state of Texas on April 9.
The epicenter for the heaviest snowfall from Winter Storm Walda was in the Black Hills of South Dakota. Not unusual for an April storm.
In this case, it was the snowfall rate that was very impressive.
At the Rapid City, S.D. airport, 20 inches of snow fell on April 9. That set a new calendar-day snowfall record for that location, topping April 18, 1970 (15.6"). Records at the airport only date to 1942, however.
The final snowstorm total at the airport site was 28.2 inches, which also blew away the record heaviest snowstorm at that site (previously 18" on Apr. 22, 2001).
A much longer period of record is in place for Downtown Rapid City. There, the storm total of 22.4 inches was the second heaviest snowstorm on record, there, topped only by a 32.1 inch snowstorm from April 12-15, 1927.
If you melt down the snow, the 1.21 inches of "liquid equivalent" precipitation on April 9 was the single "wettest" calendar day in Rapid City since May 19, 2011. Certainly desperately needed for drought relief.
Due to the heavy snow in the west, and ice to the east, a roughly 350-mile stretch of Interstate 90 was shut down from Rapid City to Sioux Falls.
The ice storm photo at right is not unusual, for, say, January or February.
A more "typical" April storm might have a sliver of heavy, wet snow on the northwest or western periphery of the storm's precipitation shield. So, precipitation types are most often either rain or wet snow.
The above right photo was taken in Sioux Falls, S.D., where significant icing downed tree limbs on April 9. That would be unusual enough.
Then, on April 10, freezing rain broke out from northwest Texas into Oklahoma and points north. One quarter inch of ice in trees was observed in Weatherford and Enid, Okla.
Light icing was even reported by KFDX in Wichita Falls, Texas early on April 10.
According to Rick Smith, Warning Coordination Meteorologist at the National Weather Service
Forecast Office in Norman, Oklahoma, the April 10, 2013 freezing rain event in Oklahoma City was the second latest freezing rain/freezing drizzle event in the spring in records dating to 1930. The only later event, there, was Apr. 17-18, 1953.
In this case, the polar cold front was so strong, and the upper-level trough remained anchored over the southern Rockies, such that precipitation that would more typically be rain, was occurring behind the front as freezing rain.
We're all used to severe thunderstorms on days with warm and humid air in place.
It's not unusual for severe thunderstorms with large hail north of a warm front, as elevated instability can support the growth of large hailstones even if the surface air is "relatively cool".
What we saw with this storm, however, was amazing.
- Grand Island, Neb. and Hays, Kan. reported hail up to nickel-size with surface temperatures around 28 degrees.
- There were several reports of tornadoes near Akron, Colo. the evening of April 8. Following a peak wind gust to 79 mph, surface temperatures crashed through the 40s into the 30s on the eastern Plains of Colorado that evening.
- One location in central Nebraska reported hail with a surface temperature of 18 degrees!
At those temperatures, you would expect to shovel snow, not hail!
The Wyoming state capital of Cheyenne had a high temperature of only 12 degrees on Tuesday during the early morning hours. This is the
third lowest April high temperature in Cheyenne weather records dating back to 1871. Late on Tuesday night, the low temperature dipped to a daily record low for April 9th of 6 degrees.
Cheyenne set a third temperature record early Wednesday morning with a daily record low for April 10 of 5 degrees. On top of these three temperature records, Cheyenne also picked up 9 inches of snow and had wind gusts up to 42 mph.
Temperatures fell below zero in the southeast Wyoming town of Laramie right before midnight on Tuesday.
By early Wednesday morning, Laramie had bottomed out at 5 degrees below zero, setting a new daily record low for April 10. This also ties as the
seventh coldest April low temperature in Laramie weather records dating back to 1948.
A bit farther south, the Mile-High City illustrated its reputation for big temperature swings.
Denver is known for its wild temperature.
After a high of 71 degrees on Monday at 2 p.m. EDT, the temperature had fallen to 22 degrees by midnight Tuesday. That 22-degree temperature reading at midnight ended up being the high temperature for Tuesday, which ties as the
sixth coldest April high temperature on record. The low on Tuesday fell all the way to 9 degrees late in the evening, which set a
new daily record low for April 9.
The Mile-High City set yet another temperature record on Wednesday morning with a daily record low of 6 degrees for April 10. In addition, this 6 degree temperature reading
ties as the fourth coldest April low temperature in Denver weather records dating back to 1872.
Very large hail in the Plains is not uncommon during the spring. What is unusual in this case is that Omaha, Nebraska,saw very large hailstones up to two inches in diameter with temperatures in the middle 30s on Tuesday evening! Not the kind of temperatures you would expect to see with hail this large.
The hail caused damage to roofs, cars and windshields according to this
article from the Omaha World-Herald.
Ahead of the cold front associated with this storm., Abilene, Texas saw temperatures rise all the way to 93 degrees around 4 p.m. CDT Tuesday. Just eight hours later near midnight, the temperature had plummeted to 37 degrees. By Wednesday morning, Abilne was reporting freezing rain and thunder.
Late Wednesday morning, the National Weather Service in San Angelo, Texas, mentioned reports of light sleet and freezing rain accumulations on elevated or grassy surfaces, "but the roads seem to be in pretty good order thanks to yesterday's 90s."
We've touched on the cold in a couple of other Wyoming cities earlier.
In Casper, Wyo., April 9, 2013, the "high" temperature topped out at a mere 13 degrees. This set a new
record coldest daily high temperature for April, dating to 1939. The old record coldest April high, there, was 16 degrees on April 11, 1997 and April 2, 1945.
During the winter of 2012-2013, only three January days in Casper had high temperatures colder than April 9. In fact, no February 2013 day in Casper featured a colder high temperature than what was observed on April 9.
Still not impressed? Casper's high temperature matched that of Fairbanks, Alaska on April 9. And Fairbanks was in a cold snap itself! Their high of 13 degrees was three degrees colder than their average
low for the day!
