OTTUMWA — Thursday’s low of 18 was well below normal for the first week of November, but it’s going to get colder early next week.
A powerful cold front will leave the Ottumwa area short of the freezing mark on both Monday and Tuesday, according to the National Weather Service. And Wednesday’s high might top out at only 32 degrees.
It’s possible the front could bring record temperatures, but probably not the ones you’re thinking about. Overnight lows for Monday and Tuesday are 10 to 13 degrees. That’s a few degrees higher than the records, set during an unusually cold period in 1986. The daytime is when the records might be set.
Record temperatures aren’t just the day’s high and low. There are also records for the lowest high temperature, and that’s what next week’s weather might challenge.
The lowest high temperature ever recorded in Ottumwa on Nov. 12 is 27 degrees back in 2014. Forecasters with the National Weather Service are only predicting a high of 25, which would set a new mark.
A record is hardly guaranteed. The cold weather is still a few days away, and slight shifts could change the picture. But it’s a reminder that winter is bearing down, and it arrives as the NWS office in Des Moines marks Winter Weather Awareness Week.
Anyone who has lived in Iowa for long knows the risks of snow and freezing rain during the winter and should have a general idea of what weather warnings mean during those months. There’s a new one this year, and it needs some explanation.
Beginning this winter, the NWS will warn of snow squall events. Those are defined as “intense, but limited duration, periods of moderate to heavy snowfall, accompanied by gusty surface winds resulting in reduced visibilities and whiteout conditions.” They may also be accompanied by rapidly falling temperatures.
Both of those ingredients are important for drivers. The limited visibility is an obvious problem. But a quick drop in temperatures can turn slush or melting snow into ice, making roads even more dangerous.
Snow squalls can be unpredictable, so the NWS will not issue watches for them. Iowa residents may well hear a snow squall warning, though, which means a squall is imminent.
People who lived in the area in January 2014 might remember a sudden blizzard warning that was issued seemingly out of nowhere. There was snow in the forecast, but what developed was much more intense than anticipated. At the time Jeff Johnson, a NWS meteorologist, called it an “instant blizzard.”
The squall line formed between 2-3 p.m. between Des Moines and Fort Dodge. It brought Ottumwa brief, heavy snow and wind gusts of 45 mph. Then it was gone. The event resembled a summer severe thunderstorm more than a snowstorm — it even produced some lightning in the Des Moines area.
It is impossible to predict such squalls too far in advance, but there is some encouraging news from the Climate Prediction Center. The center’s one-month outlook expects colder-than-average temperatures for Iowa. But the three-month outlook, which covers the coldest part of the year, expects warmer weather for western Iowa and near normal temperatures for southeast Iowa.