Midwest Weekly Highlights - February 1-7, 2009

Winter Finally Yields

Cold winter weather continued to make it's presence felt the first week of February, but when all was said and done much of the Midwest had experienced their warmest day since the fall.

There was a large difference in temperature departures first week of February. In western Missouri and Iowa, average daily temperatures were 6°F to 7°F above normal, while in the eastern half of the region temperatures ranged from 4°F to 6°F below normal (Figure 1). The largest departures were found over the Ohio Valley which lie under a deep cover of snow the first half of the week (Figure 2).

This was a mostly dry week for the Midwest, with the greatest precipitation, to 200 percent of normal, falling in the Michigan U. P. (Figure 3). Significant lake-effect snow also fell in northwestern Indiana and Ohio. Snow also fell again in the Ohio Valley adding several inches of snow on top of the ice accumulated from the the storm the last week of January (Figure 4). The heavy precipitation in the Ohio valley wiped out the last traces of any drought in Kentucky on the U.S. Drought Monitor, with the only area of Severe Drought from Minnesota across northern Wisconsin and into northern Michigan (Figure 5).

By the end of this week mild weather had melted much of the snow over the southern Midwest and significant snow cover was confined to the northern third of the Midwest, eastern Indiana, and northern Ohio (Figure 6).
 

First the Cold and Snow

The first half of the week was colder than normal as two successive cold fronts wheeled through the Midwest (Figure 7). Low pressure riding up along the second cold front on February 3 (Figure 8) brought snow to an area from Illinois through Indiana, northern Kentucky, and southern Ohio. Snow accumulated to as much as 4 to 7 inches in many of the same areas that were ravaged by an ice storm the previous week, slowing recovery efforts. Heavy snow in central Indiana caused a 20-car pileup on Interstate 69 in Noblesville, 25 miles northeast of Indianapolis . Three people died and many more were injured in the accident on February 3.

The strong winds streaming down the open waters of Lake Michigan resulted in persistent and heavy lake-effect snow in northwestern Indiana on February 3-4. The snow piled up in northwestern Indiana over a 40-hour period beginning on February 3. Over two feet of snow fell in Porter County as snow bands produced snowfall rates of 3 to 4 inches per hour (Figure 9). Porter County declared a Level 2 State of Emergency, and county schools and many businesses were forced to close for a few days while crews attempted to make roads safe and passable. Valparaiso reported 26 inches of snow, Westville 24 inches, and Kouts 23 inches from this storm alone. The heavy snow caused problems along the Indiana Toll Road in Porter and La Porte Counties, with many crashes and slide-offs reported during the evening of February 3 and the morning of February 4.
 

The Warm up Begins

Sub-zero readings were recorded over snow-covered areas of the Midwest on February 3 and February 4, and in the eastern Midwest on the 5th and 6th. Record lows were recorded in Michigan, Ohio and Kentucky on February 5-6. However, by February 5 southerly winds on the backside of the retreating high pressure system started bringing warm air into the Midwest (Figure 10). Temperatures warmed more each day, and by February 7 highs in the 50s could be found as far north as southern Iowa to southern Michigan, with 60s from Missouri into central Illinois (Figure 11) . Record highs were set in Iowa, Missouri, and western Illinois on February 6-7 on the heels of the cold air retreating from the eastern Midwest.
 

SDH