Midwest Weekly Highlights - January 9-16, 2006
The second week of January picked up where the first weekended...with anomalously warm weather and record high temperatures. This is reflected in averagetemperature departures across the region for the second week of January (Figure 1). Average daily mean temperatures this week rangedfrom 22°F to 24°F above normal in extreme north centralMinnesota to 10°F above normal across Missouri and Kentucky. The remainder of the Midwest saw average daily temperaturedepartures between 12°F and 18°F above normal. In partsof central Iowa, January 13 marked the 24th day in a rowwith above average temperatures, which has increased the demand foroutdoor supplies, such as mulch and rocks at local hardware stores. In Chicago, IL, the warm weather forced the postponement of FranVolz's popular Snow Visions ice sculpting contest. In other partsof Illinois, the warm weather was to blame for the cancellation ofcross-country skiing and snowshoeing events at the regional SpecialOlympics.
Southwesterly flow aloft during the second week of January, indicated by above normal heights in the upper atmosphere (Figure 5,Climate Diagnostics Center), brought precipitation chances to theMidwest about every two or three days, resulting in lower surfacepressures than normal for this time of year (Figure 6,Climate Diagnostics Center). Generally, surface pressures arehigher in January, and are typically associated with arctic highpressure and cold weather...something we haven't yet seen so far thismonth.
On Tuesday, January 10, a storm system rolled out of the southern Plains and into theMidwest, bringing with it widespread rains andsome snow (Figure 7). Heavy snow fell across portions of centralMissouri where some locales picked up five inches of the white stuff(Figure 8, NWS Springfield, MO). Farther east, rain and thunderstorms occurred in thewarm sector of the storm system (Figure 9), with nearly two inches of rain fallingin parts of westernKentucky, southeastern Illinois, and southwestern Indiana. At the Paducah Regional Airport, 1.89" of rain fell in 24 hours,breaking the previous record for January 10 of 1.37" set back in 1950. Further north, across the drought stricken areas of northernIllinois and Indiana, only light precipitation fell, doing little toalleviate the dry conditions (Figure 10).
Despite low temperatures in the 30's across much of eastern Iowa on themorning of January 12, Scott County officials reported that black ice was responsible for more than sevenaccidents, including rollovers, in a 45-minute span starting around7am. Fortunately, none of the accidents produced any life-threateninginjuries.
Above average temperatures continued from January 11-13 acrossthe Midwest before a cold front swept across the region on January 13. The frontal system brought some additional rains to the southernportions of the Midwest, and some light snows further north (Figure 11). Rain changed to snow across much of Illinois, Indiana, Kentucky, southern Wisconsin, and parts of lower Michigan on Friday and Saturday, January 13-14, as the storm system pulled colder air in from the northern Plains (Figure 12). The snow fell heavily at times, reducing visibilities to around a quarter-mile across parts of northern and central Illinois. Radar images from the mid-morning hours indicate where the snow was falling as the system was moving towards the northeast (Figure 13). Along the cold front, a line of strong thunderstorms, some becoming severe, raced across southern Missouri dropping hail to the size of nickels on vehicles and covering area roadways (Figure 14). Nickel sized hail was also reported across eastern Indiana and western Ohio, were some damage to vehicles occurred. Windy conditions were also common across the Midwest on Friday, with gusts exceeding 25mph common along with snow and drizzle making for a rather unpleasant January day, albeit much closer to normal conditions for this time of year. Snowfall totals from the storm system varied from 1-2" across much of central Illinois, eastern Indiana, lower Michigan, and eastern Ohio, to as much as 5" across extreme eastern Kentucky (Figure 15). This snowfall had melted by week's end, leaving only a few inches across the northern Midwest (Figure 16).
Record Breaking Warmth Engulfs the Midwest
The second week ofJanuary continued the trend of the first week of January in havingtemperatures remarkably well above average for this time of year. Part of the reason that the average temperatures across theMidwest have been so warm since the first of the year is that the NorthAtlantic Oscillation, or NAO, is currently positive which generallycorresponds to warmer than average conditions in the Midwest (Figure 17, Climate Prediction Center). Other reasons include the jet stream pattern favoring ageneral west-east flow with small day to day variations, and thepossibility that a weak La Nina event may be brewing in the PacificOcean. Whatever the reason, the warm weather has resulted in anumberof record high maximums and high minimums this week, and aresummarized in the table below:
Despite only one record high temperature on January 13, alarge portion of the Midwest was at or above 55°F,illustrating just how expansive the warmth has been during this secondweek of January (Figure 18). Indeed, locationsall across the Midwest are seeing temperatures thatare extraordinarily above average for this time of year. InSpringfield, MO, the average temperature for the first 11 days of themonth is 44.5°F, which puts them on track for the warmestJanuary on record. In LaCrosse, WI, January 16, 2006 marked the26th consecutive day with maximum temperatures at or above30°F. This ties for the sixth longest stretch of consecutivedays with maximum temperatures at or above 30°Ffor meteorological winter (Dec. 1 to Feb 28/29). The longeststretch is 33 days set in the winter of 1987-1988. In St. Louis,MO, through the 15th of January, temperatures have averaged a balmy42.9°F, which is 13.3°Fabove average for this time of year, and currently ranks as the secondwarmest January on record, behind only 1880 with an average temperatureof 46.8°F. A similar situation exists in Columbia, MO, wherethe average temperature through January 15 was 42.0°F, some14.2°Fabove average. Currently, this also ranks second all-time, behindthat of the January of 1933 which had an average temperature of42.1°F. In Chicago, IL, January 16 was the 25th consecutive day aboveaverage, signaling the warmest such period since 1939. Inaddition, the minimum temperature in Chicago has failed to dip below20°F so far this month when nearly eight days below 20°Fare normal for January. As if these are not enough, both Madison,WI and Milwaukee, WI are recording their warmest first two weeks ofJanuary on record, both averaging 15.3 and 14.0°F above averagerespectfully.
Will this warmweather linger into the third week of January, or will cold airfrom Canada dump into the region and end these streaks? Findout innext week's edition of the Midwest Climate Watch.