IOWA PRELIMINARY MONTHLY WEATHER SUMMARY – JANUARY 2020
General Summary: Temperatures averaged 23.0 degrees or 3.6 degrees above normal while precipitation averaged 1.27 inches or 0.35 inches more than normal. January 2020 ranks as the 39th wettest and 38th warmest in 148 years of observational records. A warmer and wetter January last occurred in 2017.
Temperatures: Statewide average temperatures in January were unseasonably warm. Eastern Iowa experienced the warmest conditions where positive departures of up to six degrees were reported in the monthly averages. Western Iowa was still warmer than average, though by only a few degrees above the 30-year climatology.
Twenty-two days in January had statewide average temperatures above average beginning with an extended period over the first nine days of the month. The warmest day of the period was January 1st with an average temperature of 33.9 degrees, 13.5 degrees above normal. Daytime highs reached into the mid 50s across southern Iowa. Unseasonable coldness returned to the state from the 15th to the 22nd. During this period, an especially frigid day occurred on the 18th with morning lows at a majority of stations in the negative single digits; the average low was -4 degrees, 14 degrees below normal. Daytime highs averaged at 16 degrees, 12 degrees colder than normal. The statewide average temperature was 1.6 degrees, 17.5 degrees below normal. A second stretch of unseasonable warmth lasted from January 22nd through the 31st. Temperatures averaged above eight degrees for six of those days. The final day of January was the warmest of the period with daytime highs ranging from the mid 30s north to low 40s in the south.
January’s statewide average maximum temperature was 30.1 degrees, 1.9 degrees above normal while the minimum temperature was 15.2 degrees, 5.0 degrees above normal. The month’s high temperature of 63 degrees was reported on the 9th in Bloomfield (Davis County) and Centerville (Appanoose). This reading was on average 31 degrees warmer than normal. Logan (Harrison County) recorded the lowest morning temperature of the month with a -16 degrees reading on the 21st, 26 degrees below average.
Heating Degree Day Totals: Home heating requirements, as estimated by heating degree day totals, averaged 9% below normal and 10% less than seen last year. Heating degree totals thus far this heating season are running 4% below normal and 5% less than at this time last year.
Precipitation: A majority of reporting stations across Iowa reported above average precipitation with the largest positive departures of one to two inches across southern portions of the state. Measurable precipitation fell on 22 days during the month with totals ranging from 0.45 inch in Rock Valley (Sioux County) to 3.03 inches at a station in Bloomfield (Davis County). Above average snowfall also blanketed much of the state, with a statewide preliminary average snowfall of 11.2 inches, 3.5 inches above average. This ties 1905 and 1918 as the 20th snowiest Januaries in 133 years of records; the CoCoRaHS station at Algona 0.7 SE (Kossuth County) reported the highest monthly total of 21.6”.
The first measurable snowfall of 2020 occurred across much of Iowa from January 2nd through the 3rd. Northern Iowa was blanketed with the heaviest totals as anywhere from four to six inches was reported across the first few north-central tiers of counties. Kanawha (Hancock County) reported 6.9 inches.
The most widespread snowfall event occurred on January 17th through the 18th as a strong low pressure system moved through Iowa. Snow totals across much of the state were in the three to six inch range with higher totals in northern Iowa; Ringsted (Emmet County) reported eight inches. The statewide average total was 3.7 inches.
The final widespread event occurred mainly over January 22nd through the 23rd as a stubborn low pressure system moved through northern Missouri. Snowfall occurred in advance of the system as well as on the backside of the low as it propagated east. Measurable snow was reported statewide, though Iowa’s southeastern quadrant observed totals between three to six inches. Stations in Amana (Iowa County) and Bloomfield (Davis County) reported totals of 8.0 inches and 8.4 inches, respectively.
Justin M. Glisan, Ph.D.
State Climatologist of Iowa
Iowa Dept. of Agriculture & Land Stewardship
Wallace State Office Bldg.
Des Moines, IA 50319
Telephone; (515) 281-8981
WEATHER BY DISTRICTS
|TEMPERATURE (F)||HEATING DEGREE DAYS||PRECIPITATION (inches)|
|January 2020||January 2020||Since Jul., 1, 2019||January 2020||Since Nov.1, 2019||Jan 2020|
|* Departures are computed from 1981-2010 normals.|
|The weather data in this report are based upon information collected by the U. S. Dept. of Commerce, NOAA National Weather Service.|