It has been pretty evident for weeks that September was going to end up in the state record books for precipitation, the only question was the final total.
State climatologist Justin Glisan says the preliminary numbers show a statewide average of about 8 inches. “And that’s over double what we expect –it’s about three and a half inches is the expectation across the state, so 4.5 inches above normal,” he says. That puts the month in the top five for records. “This is around the 4th wettest September on record, and that’s rivaling the September of 2018, which was also together the second wettest year on record for the state of Iowa,” Glisan says.
Glisan says it takes a little time to collect all the local rainfall records, but he says it is certain that the capital city was very close to breaking the record. “So Des Moines, with a period of record going back into the mid 1800s, 14 and a half inches,” he says, so this is the second wettest September on record behind 1914, which was 14.81 inches. So we were about 32 one hundredths off of the record total for September.” Glisan says is was the third wettest month ever for Des Moines with the wettest month on record back in June 1881 at 15.79 inches.
Glisan says the weather patterns aligned so there was plenty of moisture in the air, and conditions were right for it to fall. “It hasn’t been really windy out there. So these thunderstorms will pop up and they’ll just drain over the same part of the state. So you’re thinking west central into central Iowa and then over into eastern Iowa is where we’ve seen pockets of well above average two to three times in fact, what we would expect as a monthly total for September,”Glisan says.
All the rain overshadowed the temperatures in September, which averaged 69 degrees. “The normal 30-year climatology average temperature is about 64 degrees, so about five degrees above average. So, preliminarily about the seventh warmest September in 154 years of records,” he says. Glisan says previous strong El Nino events like the one we are in now did have warmer temperatures through fall alon with near normal to slightly wetter conditions.
