The improved, near to above normal rainfall for much of the HSA in October increased the flows in the rivers and streams during the month. However due to the moderate to extreme drought in progress across the HSA during the month, the heavier rain events on the 13th/14th and 24th/25th did little more than produce minor and brief within-bank rises on the streams and rivers.
October 2012 rainfall ranged from near and below normal across the northwest quarter of the HSA, to much above normal from portions of far northeast IA into central WI, and from north of La Crosse into the Neillsville WI area. The bulk of all the rain during October fell on the 13th into the 14th and on the 24th into the 25th. The first week of the month was dry. A passing low and cold front brought light to locally moderate rains to the HSA on the 8th into the 9th. A strong and slow moving low brought showers and thunderstorms with widespread moderate to heavy rains to mainly the southeast two-thirds of the HSA on the 13th and 14th. Another slow moving low brought mainly light rains to most of the HSA on the 18th to the 20th. A strong low and cold front brought showers and thunderstorms with widespread moderate to heavy rains to the northwest two-thirds of the HSA on the 24th and 25th. The month ended dry from the 26th to the 31st.
Normal October rainfall ranges from around 2.25 inches over the central third of the HSA, to around 2.50 inches across the northern and southern thirds. Totals for this month ranged from 60 to 80 percent of normal in the far west and northwest end of the HSA, to 150 to 250 percent of normal in parts of far northeast IA into central WI and north of La Crosse into the Neillsville WI area. Most totals for October were 100 to 150 percent of normal. Extreme totals recorded for the month ranged from 1.43 inches at Austin MN in Mower Co. MN and 1.77 inches at Dodge Center in Dodge Co. MN, to 5.32 inches at Friendship in Adams Co. WI and 6.30 inches at Postville IA, on the Allamakee-Clayton Co. line.
Temperatures for October 2012 averaged 45 to 49 degrees. This was near to 2 degrees below the normals. Temperatures were above normal on the 1st to the 3rd, near normal on the 4th then much below normal on the 5th to the 7th. Temperatures cycled above and below normal from the 8th to the 25th, with some much above normal readings on the 21st to the 24th. The month finished with below normal temperatures from the 26th to the 31st. Extremes for the month ranged from lows in the middle teens to middle 20s on the mornings of the 12th and 29th, to highs in the 70s on the 3rd.
Due to the two larger rain events in October, flows in the rivers and streams of the HSA improved a bit, with flows below to near normal during the month. Crops matured early and harvesting activities remained around 3 weeks ahead of normal during the month. Harvest reports indicated minor to major yield reductions across the southeast half of the HSA due to the season long dryness and drought. Reports from the northwest third of the HSA, where rains were closer to normal during the first half of the growing season, indicate production fared better with minor yield reductions to near normal yields.