Snow and weather: Snowpack totals vary throughout the state, El Niño patterns expected to weakenWritten by Natasha Wheeler
Considering the statewide average for precipitation in Wyoming over the last three-month period from November 2015 through January 2016, this year falls right at average.
“Over 121 years of record, we are in the 60th wettest year, basically dead middle of the road,” notes meteorologist Chris Jones with the National Oceanic and Atmospheric Administration (NOAA).
But, this statistic is misleading for those taking a closer look at specific regions within the state.
“It just depends on where we’re at. At times, we’ve had a favorable westerly flow, which has kept snowfall in our far western basins. We’ve also had storms that have emerged on the plains of Colorado and really provided some snow in southeast Wyoming,” Jones explains.
In those two regions, snowpack currently ranges from about 90 percent of median to 115 percent of median. Above median snowpack is greatest from Laramie to Casper in the basins fed by the Laramie Range.
The Wind River, Upper Green River and Yellowstone Basins range between 75 and 85 percent of median, and areas of the Bighorn Basin have snowpack as low as 57 percent of median.
“This is playing out similar to what we thought might happen with an El Niño type year, which favors precipitation across the southern tier of the state, while the north is more likely to be dry,” he continues.
Snow has been scarce in the Big Horn Mountains, as well as at the southern end of the Wind River Range, where the prevailing weather patterns have not been favorable for precipitation.
“It’s been a very active year across the desert southwest of the United States, the four corners region and heading out onto the Central Plains. That just doesn’t favor the areas east of the divide that are in the central and northern parts of the state,” he remarks.
One exception has been Casper, where a number of recent storms have passed through, bringing in snowfall.
Fortunately, it is still early in the year relative to precipitation totals, as April, May and June have historically been the wettest months in Wyoming, Jones says.
“Obviously, we hope some precipitation might come in the form of rain by the time we get to June, but those wet snows starting in April and keeping that pattern into June make a difference, and we certainly saw that last year,” Jones says.
Last year, Wyoming experienced a near-record dry year through March, but within a few weeks in May and June, the whole season turned around. For this year, it is still too early to tell how spring snows and rains will affect precipitation totals.
“Right now, the outlook is still that the spring months across the southern third of the state could stay wet, according to the most recent outlook from January 21, from the Climate Prediction Center,” Jones notes.
In the next six to eight weeks, the El Niño weather pattern impacting the region is expected to weaken, possibly creating a more favorable pattern for Wyoming precipitation in the spring months, although it remains to be seen how that might play out.
As for temperatures, statewide averages are again somewhat misleading related to specific map dots within Wyoming. For example, on Feb. 10, midday temperatures were as low as 10 degrees Fahrenheit in Afton while Buffalo experienced 59 degrees at the same time.
“There can be a stark difference across the state,” Jones remarks.
Statewide, the average temperature in Wyoming for the three-month period of November, December and January is 22.7 degrees. The warmest record for the same time period occurred in November 1980 to January 1981, with an average of 29.7 degrees.
“This year, we tied with another El Niño year in 1982-83, at 24.5 degrees, which is significantly cooler than the record,” he stated.
Last year was warmer as well, at an average of 26.0 degrees between Nov. 1 and Jan. 31.
“As we head toward the spring months, there is a fairly good chance of temperatures staying above normal,” predicted Jones.