February 8-14, 2003
The week of February 8-14 proved to be the quiet before the storm, as most of the period was inactive until a very strong low pressure system entered the region on the 14th. The weekly precipitation totals reflect this late arrival, bringing moderate to heavy rain to southern portions of the Midwest (Figure 1) . While Missouri and some of the lake effect belts were the only locations receiving above normal amounts of precipitation for the period (Figure 1a), there was more rain that fell on the 14th that will be seen in the next totaling period due to the substantial morning bias in daily cooperative network observation times. During the period, there was a strong but fairly dry cold front that passed through the region on February 11-12, with considerable lake effect snow measured on the downwind side of Lake Michigan (Figure 2). The cold front kept temperatures well below normal in most of the Midwest, especially in the north (14-16°F below normal), although the southwestern portion of the region was raised to just above normal for the week by the warm advection ahead of the late-period storm (Figure 3). Unfortunately, most of the precipitation fell away from problem drought areas, and the intensity and distribution of drought conditions in the region did not change much (Figure 4, National Drought Mitigation Center).
<p>Interestingly, the strong but dry cold front on the 11th resulted
in the formation of a very weak line of small convective cells (Figure 5, National Weather Service). The first Midwest severe weather warnings of the year were issued in response to 60 mph winds accompanying the front (Figure 6, Storm Prediction Center). Radar velocity imagery from the College of DuPage NexLab displayed the intense winds associated with the frontal convection (Figure 7). Some power lines and trees were knocked down in the Peoria, IL, area. The sustained winds of 30-40 mph following the frontal passage produced the fascinating phenomenon known as snow rollers across much of central Illinois. A staff member of the MRCC documented local snow rollers in Champaign, IL. For more on the snow roller event, please see the NWS-Lincoln web page on the phenomenon. However, the main feature of the week was the intense storm starting on the 14th; this multi-day storm and its Midwestern impacts will be discussed in the next weekly summary.