As summer-like weather lingers, winter outlook remains uncertain
IRON MOUNTAIN — The Iron Mountain-Kingsford area hasn’t experienced freezing temperatures since May and will likely set a record this fall for the latest first frost of the season.
The record for the latest first frost is Oct. 14, set in 2013, according to observations at the Iron Mountain-Kingsford Wastewater Treatment Plant.
Lows are expected to remain above freezing through the end of this week, the National Weather Service says.
Although overnight temperatures have remained mild, September’s weather wasn’t exceptionally warm. Readings for the month averaged 60.2 degrees, which is 1 degree above the mean for this century and 2.8 degrees above the norm since record-keeping began in the early 1900s.
The highest reading was 83 degrees Sept. 20 while the lowest was 39 degrees on Sept. 28. Daily highs were generally in the 70s, dipping only to 62 on the coldest day, which was Sept. 23.
Rainfall totaled 2.69 inches in September, which was about three-quarters of an inch below normal.
Highs this weekend may finally drop into the 50s. The Climate Prediction Center has called for a 70% chance of above-average temperatures in October and a 40% chance of above-average precipitation.
The long-range outlook, however, is neutral on both temperatures and precipitation through January.
CPC forecasters expect La Nina conditions to prevail this winter, which can bring cold and snowy weather to areas around the Great Lakes. La Nina, the flip side of El Nino, is the periodic cooling of the central Pacific Ocean that affects weather patterns around the globe.
Often during La Nina, a greater number of weak storms advance from the west to the Midwest and Great Lakes. This can keep snowfall totals at normal or even above-normal levels with many smaller events occurring, rather than a blockbuster snowstorm or two, according to AccuWeather.
“Not all La Ninas are created equal and there can be variations in weather patterns that develop,” AccuWeather meteorologist Brian Lada said.
Even with the presence of La Nina, there are weak or conflicting signals among long-range temperature forecasting tools, National Weather Service forecaster Scott Handel said.
With modest rainfall this past month, the weekly U.S. Drought Monitor as of Thursday showed abnormally dry conditions in much of the Upper Peninsula, including all but the northern reaches of Iron and Dickinson counties. In Wisconsin, Florence and Marinette counties were also listed as dry.
There was extreme drought in several counties in northeastern Minnesota and at least some level of drought over all of northern Minnesota.