With all-time high or near-record temperatures expected in the low 70s today in parts of southern Iowa, December is starting with a very warm start to the season.
State climatologist Justin Glisan said November was also slightly warmer than normal, as well as drier. âThe average temperature was around 39 degrees and it’s just over two degrees above average,â says Glisan. âOn the precipitation front, we were drier than average across the state. We had pockets of precipitation that were slightly above average, but overall slightly less than an inch below average. “
Although winter does not officially start until December 21, snowfall is not unusual for this time of year, although there weren’t many flakes in November.
âWe were below average for snowfall across the state, two to three inches, and some resorts didn’t have snowfall in November,â says Glisan, âwhich is not extreme but also remarkable â.
The forecast models for the month of December show a trend towards more spring temperatures compared to fall or winter. âWe have seen a persistent signal in which we are seeing above average behavior for warmer temperatures,â Glisan said. “We’ve certainly seen this over the past week with temperatures in the 50’s and 60’s, ranging from 15 to 25 degrees above average, depending on your location.”
La Nina’s weather regime is expected to start influencing our region’s climate soon, but Iowa is at the center of two converging fronts – so it’s a blow to what we might get for snow or rain.
âIf we look at the precipitation forecast for December, it shows us that classic signing from La Nina in which we have an above-average chance of wetter conditions in the Ohio Valley, the Great Lakes and up north. âWest Pacific, drier probabilities south of us and Iowa sits right in the middle, âhe said. Glisan notes that December and January are generally the driest months of the year in Iowa.
The national meteorological service will not make its forecasts on the probability of a White Christmas until around December 15, or ten days from the 25.
(Pat Powers, KQWC, Webster City contributed to this story.)