Meteorologist Chad Gimmestad described this fall’s weather in a simple phrase: It’s hot.
“We have warm air over the whole southwest that goes over Oregon,” said Gimmestad with the National Weather Service. “There’s some areas where there was recovery from the drought the first half of this year, but that’s fading fast.”
Boulder on Thursday had a record temperature of 72 degrees, trumping the record of 71 degrees in 1926, according to a tweet from local meteorologist Matt Kelsch.
Longmont came close to a record temperature on Wednesday with a high of 76 degrees, which was just two degrees short of the record set in 1939, said meteorologist Greg Byrd.
The warm temperatures and dry soil this year is an effect of La Niña, a climate pattern that occurs in the Central Pacific Ocean when temperatures are colder than normal. The ocean temperatures affect the atmosphere wave patterns and the jet stream moves further north bringing wet weather to the northern part of the country and dry weather to the southern part.
With the jet stream up north, areas such as Washington and British Columbia are feeling the opposite of what Colorado is experiencing.
“They have had tremendous rain,” Gimmestad said. “They are on the other side of this high pressure system. We are missing out on it.”
— Matthew Kelsch (@mattkelsch) December 3, 2021
In November, Boulder experienced its first measurable snow of the season. Even with that small amount of snowfall, Boulder County is still far below what is should be for this time of year, said Jeff Weber, program manager with University Corporation for Atmospheric Research.
“On an average we get about an inch in September, about seven inches in October (and) about 12.7 inches in November,” he said. “We should have received about 20 inches of snow by now.”
Not only is the climate today warmer overall than it was when the last records were set, but the West Coast has been in a drought since the 1990s, Weber said. The warmth is a consequence of the dryness, he said.
The sun emits sensible and latent heat, Weber said. Sensible heat is what we feel. It’s the heat that warms the earth while latent heat is the amount of energy from the sun that is involved in changing the phase of water. The energy converts water into vapor, which rises in the atmosphere.
“When we are in an extremely dry period as we are now, all of the energy comes in as sensible heat,” he said. “There is no moisture around. As we continue to get dryer and dryer, our temperatures are expected to stay warm and all of the sun’s energy goes toward the heating of the earth rather than taking that water from a liquid phase and transferring it into a gas phase.”
Boulder County and the U.S. Forest Service recently enacted Stage 1 fire restrictions because of the dry conditions and recent fires. To lift the restrictions, it would take a heavy amount of perception, Byrd said.
“I have not looked ahead that far, but the patterns don’t seem to be conducive to a heavier precipitation,” he said.
So will the snow come in time for a white Christmas?
Weber thinks so.
“There will be a break in the current pattern around Dec. 8,” he said. “I forecast getting us down into single digits. It’s forecasted to have a low of 8 (degrees) and a high of 30 (degrees). It will finally feel like winter,” he said.