January 2000
Temperature and Precipitation Anomalies.
January was very much above normal during the first half of the month (Figure 1a) , and very much below normal in the second half (Figure 1b). Some places in western Ohio suffered from a change of more than 20 Deg F from the first half of the month (10 Deg F above normal) to the latter half (12 Deg F below normal). At about mid-month, the North Atlantic Oscillation pattern became very negative, causing mid-tropospheric troughing to be established over the central and eastern Midwest when combined with the existing upper air forcing of a strong La Niña. This upper air pattern allowed for more frequent incursions of cold air over the Midwest, replacing the warm ridging of the first half of the month (Figure 2). Overall, the Midwest had its 51st warmest January in 106 years, slightly above normal when the two halves of January are combined (Figure 3). No individual states were in the top or bottom 30 ranked months for January temperature.
The Midwest had its 42nd driest January since 1895, with two main areas of moisture corresponding to storm tracks through the Ohio Valley and the upper Midwest (Figure 4). An especially large amount of warm precipitation fell on January 3rd and 4th in the Ohio Valley, with station totals of 1 to 3 inches of rain common in this event (Figure 5). Snow cover was well below normal in the first half of January, but achieved near normal levels and spatial pattern by the end of the month in all states except the dry western portions of the Midwest. All individual states were within 0.34 inches of normal for January, so none ranked in the top or bottom 30 months for January precipitation.
A strong low pressure center and frontal system passed through the Ohio Valley on January 3-4, accompanied by severe thunderstorms that generated dangerous tornadoes. A total of 12 tornadoes were generated by the outbreak through Arkansas and Mississippi and northward into Kentucky (Figure 6). A strong F-3 tornado hit the town of Owensboro, where timely warnings prevented deaths despite the destruction or damage of 750 buildings and homes. In Webster, KY, 12 people were injured by a tornado, most of whom were living in mobile homes. Many more locations in southern Illinois and Indiana and throughout northwestern Kentucky were also damaged by straight-line winds. The President declared a major disaster for 11 counties in northwestern and north central Kentucky (Figure 7). More information can be obtained at the FEMA website.
A major weather-related calamity occurred in northwestern Missouri on January 23 around 1:30 PM. On a busy highway north of Kansas City, 10 people died in a multi-car pile-up triggered by an out-of-control car sliding across a median and hitting oncoming traffic head-on. A total of 17 cars and 5 trucks were involved. Local weather observations indicate that the effects of a light snow were compounded by a freezing fog event that lowered visibilities and further reduced traction on cold icy road surfaces. A total of 430 weather-related accidents were reported in and near Kansas City by evening.