With record or near-record temperatures expected in the low 70s today in parts of southern Iowa, December is getting off to a very unseasonably warm start.
State climatologist Justin Glisan says November wrapped up slightly warmer than normal, too, as well as drier. “The average temperature was about 39 degrees and that’s a little over two degrees above average,” Glisan says. “On the precipitation front, we were drier than average across the state. We did have pockets of slightly-above-average precipitation but overall slightly under an inch below-average precipitation.”
While winter doesn’t officially start until December 21st, snowfall isn’t out of the ordinary for this time of year, though there weren’t many flakes flying during November.
“We were below-average on snowfall across the state, anywhere from two to three inches, and there were some stations that didn’t get any snowfall in November,” Glisan says, “which is not extreme but also remarkable.”
The forecast models for the month of December are showing a trend toward more spring-like temperatures versus fall or winter. “We have seen a persistent signal in which we’re seeing above-average behavior for warmer temperatures,” Glisan says. “We’ve definitely seen that over the last week with temperatures in the 50s and 60s, anywhere from 15 to 25 degrees above average, depending on your location.”
The La Nina weather pattern is expected to start influencing our region’s climate soon, but Iowa is in the center of two converging fronts — so it’s a toss-up as to what we might get for snow or rain.
“If we look at the precipitation outlook for December, it’s showing us that classic La Nina signature in which we have above-average chances of wetter conditions in the Ohio Valley, Great Lakes and up to the Pacific Northwest, drier probabilities south of us and Iowa happens to be right in the middle,” he says. Glisan notes, December and January are typically Iowa’s driest months of the year.
The National Weather Service won’t be making its forecast for the likelihood of a White Christmas until around the 15th of December, or some ten days out from the 25th.
(Pat Powers, KQWC, Webster City contributed to this story.)