It was 42 days, six weeks, between January 8 and February 20 since a temperature of 40 degrees or higher was reported in the Wisconsin River valley from Wausau to the river's Lac Vieux Desert source according to Wisconsin Valley Improvement Company (WVIC), Wausau. The National Weather Service (NWS) forecast all headwater basin counties to reach or surpass 40 degrees Feb. 20. With a January thaw not having been unusual during recent winters, 40 degrees instead of 32 degrees has become a winter weather benchmark.

WVIC observes Wisconsin basin hydrology to guide its operation of 21 headwater storage reservoirs to regulate a uniform flow in the state's largest river. Reservoir operation is regulated by the Federal Energy Regulatory Commission.

Because the high altitude jet stream steering winds were split to the north and south, precipitation was absent from the Wisconsin Valley Feb. 14-20. Aided by some moderate air from the Pacific Ocean, temperatures, however, rose from the depths of double digit below zero cold and felt relatively "balmy" to some. Rising temperatures and lengthening amounts of daylight stirred yearnings for spring in others.

From WVIC and NWS sources, high temperatures Jan. 8 were 44 degrees at Willow reservoir in western Oneida County, 48 degrees at Rhinelander and 46 degrees at Wausau. There was little or no snow on the ground.

The coldest high temperatures by location in degrees and date thereafter were Willow three Jan. 23, Rhinelander minus one Jan. 26, and Wausau four Jan. 22 and Feb. 12.

The coldest low temperatures all occurred on Feb. 7 when there were eight to 10 inches of snow from a storm Feb. 3-4. By location in degrees they were Willow minus 26, Rhinelander minus 25, and Wausau minus 17.

For the period Feb. 14-20, low temperatures at Willow were minus 16 Feb. 16 and minus 17 Feb. 17. The coldest low at Wausau was minus seven degrees Feb. 16. Temperatures at both Willow and Wausau broke the freezing mark Feb. 17. The high Feb. 18 was 36 degrees at Wausau. Resulting weekly average temperatures were below normal by four degrees at Willow and two degrees at Wausau.

The warm up was to be short lived. Cold temperatures were forecast to return. The NWS Climate Prediction Center said very cold Arctic air for this time of the year - temperatures could be 30 degrees below normal - would pour down over the Wisconsin Valley Feb. 23-26.

Wisconsin Valley weather has not been normal since mid-October. Precipitation has been below normal and temperatures have been both above and below normal. Snowfall has been below normal. Looking ahead, the Climate Prediction Center said its forecasts indicate that El Nino conditions would continue to weaken through April, and that thereafter, its consensus forecast was for near-normal conditions during May-October. The Center also said that areas of the world usually affected by El Nino may continue to experience related impacts during the next 2-3 months.

In the Wisconsin Valley, normal precipitation would be two inches in March, two and a half inches in April, three and a half inches in May, and four to four and a half inches in June.

Due to the decline in natural, or base flow in the Wisconsin River, WVIC has set target flows as 1,900 cubic feet per second (cfs) at Merrill and 2,600 cfs at Wisconsin Rapids. Deep cold had penetrated soil not covered by snow earlier in the winter and locked soil moisture as ice. Weekly average regulated flow Feb. 14-20 ran 60-80 percent of normal.

Temperatures over the Wisconsin Valley at 1:00 p.m. Feb. 20 were in the mid-40s and over 50 degrees. Low temperatures Feb. 23-26 were forecast to range from the single digits to double digits below zero. A day or two of mild temperatures cannot unlock the Wisconsin River basin from both the deep penetration of frost or the lag between increasing solar energy and warming taking hold. Spring break up along the 430-mile long river begins to creep northward from Boscobel and Muscoda in the lower valley to Stevens Point and Mosinee by mid to late March. It may not fully extend into the Northwoods headwaters until mid-April.

Reservoir operation will continue in winter release mode. Reservoir storage was 31 percent of capacity Feb. 16. Release from reservoirs of 719 cfs in flow contributed 41 percent to the regulated flow of 1,775 cfs Feb. 10-16.

-End of Report-