It’s May, it’s cold, it’s normal
May 10, 2013
EAGLE COUNTY — The jet stream is to bless and/or blame for our cool, wet weather.
Chris Tomer, meteorologist with Denver's Fox 31 television, explained that the jet stream is bringing cold, wet weather from Canada.
The jet stream is a river of air high in the atmosphere that guides weather systems. You need to know that. There'll be a quiz.
"We've had the same jet stream pattern for the past two and a half months," Tomer said. "We've picked up half of our snow for the winter during that time."
Thursday, Tomer forecast rain in Denver and snow in the foothills, and both showed up. Viewers send pictures for him to put on the air, and Thursday's pictures seemed to indicate a certain winter weariness.
"I could tell when people sent me pictures this morning that they'd had enough. There were lawn furniture and bird feeders covered in show," Tomer said Thursday afternoon.
On the other hand, the folks at Arapahoe Basin are positively aglow. They're not closing the ski season until someone pulls the plug on the life support system.
Arapahoe Basin was hammered with 12 inches overnight Thursday. The Eisenhower Tunnel got 16 inches — heavy, wet snow that's good for making snowballs to throw at your kids.
"That snow report you saw this morning was accurate — 12 inches of fresh snow, just in time for another weekend of live music and the best skiing in Colorado," said Adrienne Saia Isaac, marketing and communications manager with Arapahoe Basin. "We're still 100 percent open. We're not scheduled to close until June 2, and we'll see how long we can keep the season rolling."
Warmth is on the way, Tomer said. This weekend or early next week it should warm up and the jet stream could move back north. There's a big high pressure coming in and Tomer is forecasting 80s in Denver and 60s in Vail.
After months of below average snowfall, those April storms brought the moisture Coloradans had been hoping for all winter. The heavy, wet snow pushed snowpack totals to near normal in the northern river basins, said the Natural Resource Conservation Service.
And because the new snow is bright white, nothing has even started melting above 10,000 feet, Tomer said.
The snowpack has two dust layers. As the weather warms and the snow melts down to those dust layers, the dust will help it melt faster, Tomer said.
April's cool, wet weather delayed the expected increase in reservoir storage volumes. It'll get better, the conservation service said.
Reservoir storage across the state is at 74 percent of average. The late season snowfall and additional runoff should extend water supplies further into the summer season. Streamflow forecasts improved 20 percent from last month. The Colorado and its headwaters should see near average flows, the conservation service said.
Lingering chill suppressing tornadoes
And there's more good news. Cool weather from the Rockies to the East Coast is keeping a lid on the number of tornadoes for 2013.
Generally, cooler temperatures and drier air mean fewer thunderstorms, said Harold Brooks, research meteorologist with NOAA's Severe Storms Laboratory.
The cool air forces the base of thunderstorm clouds higher off the ground. That limits both the number of tornadoes and the wind gusts, Brooks said.
"The 12-month period from May 2012 to April 2013 was remarkable for the absence of tornado activity in the U.S.," Brooks said.
Tornado Alley saw 197 tornadoes over those 12 months, Brooks said. Since 1954, the previous low was 247 tornadoes in the 12 months before May 1992.
Staff Writer Randy Wyrick can be reached at 970-748-2935, and firstname.lastname@example.org