Midwest Weekly Highlights - February 8-14, 2005

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Quiet Weather Continues through Mid-Month

Only one major weather system moved through the Midwest during the second week of February.  Although it was not an exceptional storm, it did bring bring significant precipitation to most of the region.  For most of the week, though, mild and generally tranquil weather was the rule.

Precipitation for the week was well above normal over almost the entire region (Figure 1).  The exception was northern Minnesota where precipitation was less than 75 percent of average for the week.  In western Iowa and southwestern Minnesota, precipitation for the week was more than 700 percent of normal.  Note, however, that February is climatologically the driest month of the year across most of the Midwest, with precipitation for the month ranging from less than a half in in northwestern Minnesota to 3.50 inches along the Ohio River (Figure 2).  Actual amounts for this week were from 1.00 to 1.80 inches in a broad band from southwestern Iowa across Missouri, central Illinois, Indiana, and the western half of Kentucky (Figure 3).

Temperatures this week were well above normal.  Most of the region experienced temperatures ranging from 7F to 11F above normal (Figure 4).  The exception was an area from southwestern Iowa through the western half of Missouri, where temperatures were only 1F to 5F above normal.
 

One Storm, Lots of Rain

A high pressure system dominated Midwest weather early in the period.   By February 12 high pressure along the Gulf Coast combined with a developing  low pressure system over Colorado produced southwesterly winds across the Midwest, pushing much warmer air into the region.  The warm air reached well into Minnesota and Wisconsin, where highs reached the low to mid 50s (Figure 5, Unisys).  A number of high temperature records were set in Minnesota and Wisconsin.

High Temperature Records Set February 12

Alexandria, MN	48	45 in 1974 and 1976
Glenwood, MN	54	47 in 1990
Benson, MN	54	51 in 1990
Willmar, MN	52	51 in 1987
Little Falls, MN	50(T)	50 in 1976
Cambridge, MN	54	52 in 1990
Fairbault, MN	55	52 in 1977 and 1987
Rice Lake, WI	46	45 in 1976
Eau Claire, WI	50	47 in 1990

By February 13 a well-organized and strong low pressure system was located on the eastern Kansas-Nebraska border (Figure 6).  Precipitation extended from the low east into Indiana and northward into Minnesota and Wisconsin.  Cold air remained entrenched near the surface in southern Michigan which resulted in freezing rain over southern lower Michigan late on February 13 and early February 14.  From 0.25 to 0.50 inches of ice accumulation was reported, and tree branches and power lines were reported down in a number of Michigan counties.  As cold air filtered in behind the storm rain changed to snow over southern Minnesota and west-central Wisconsin, leaving accumulations of 1 to 3 inches.  Further south, heavy showers and even a few thunderstorms dropped from 0.50 to 1.50 inches of rain on an area from Missouri through Indiana.  By the morning of February 14 the storm was located over southern Lake Michigan.  Rain was still occurring in Indiana and Ohio, while some light snow fell across eastern Wisconsin into northern Illinois.  In its wake the storm set a number of new daily precipitation records in Iowa, Minnesota, and Wisconsiin, with amounts in the 0.50 to 0.80 inch range.

Wet Weather Keeps Rivers in Flood

Higher than normal precipitation in February following a very wet January across the central Midwest is keeping many rivers at or above flood stage.  Minor flooding was occurring along the Illinois River as the result of recent rain, and moderate flooding was forecast to occur over the next week.  Other rivers continued in flood in Iowa, Missouri, Indiana, and Ohio, with the most rivers in flood found in Illinois and Indiana (Figure 7, USGS).  Seven-day average streamflows were well above normal across much of the central Midwest (Figure 8, USGS).