November 1-9, 2004
Midwest Weekly Highlights - November 1-9, 2004
A Wet Start to November in the Southern Midwest
A strong low pressure center moved from the southern Plains into the Midwest on November 1st, starting the month with heavy rain in Missouri, southern Illinois, and southern parts of the Ohio Valley. Many locations in the southern Midwest received 2-4 inches of rain during the November 1-9 period (Figure 1), but dry areas of the Midwest were only grazed with modest amounts of precipitation. Most of Minnesota and Wisconsin received less than 25% of normal rain amounts for the period (Figure 2). With the strong low pressure dominance in the first half of the period, warm air intruded far northward into the Midwest, although the region cooled after a final strong cold frontal passage on the 4th. The wetter areas were also the cooler and cloudier zones, sticking close to normal temperatures, while the dry areas in the northwestern Midwest were 5-8°F above normal for the nine day period (Figure 3). The previous drought and abnormal dryness in southern Missouri was removed during the period, along with some of the southern edges of the zone of abnormal dryness stretching from southwestern Iowa to eastern Michigan (Figure 4, National Drought Mitigation Center). The period ended with a reinforcing shot of cold air that brought almost all of the Midwest well below freezing simultaneously for the first time this year (Figure 5).
Some Heavy Rain and Violent Weather
As November began, a very deep mid-level trough (Figure 6, College of DuPage - COD) was steering a strong surface low center northeastward through the Midwest. Rain totals of 2.97 inches and 3.51 inches were measured in Joplin and Springfield Missouri, respectively. Embedded in the heavy precipitation were a few severe storms that developed quickly and spun-up short-lived tornadoes in Missouri and Illinois (red dots on (Figure 7, Storm Prediction Center). The second tornado was on the ground in east central Illinois during mid-evening on the 1st; the storm associated with the tornado was visible on the regional composite radar at the time (furthest east red returns on Figure 8, U.S. Weather Research Program Image Archive). No injuries were reported in either case, but 100-200 yard wide damage paths more than a mile long resulted in the destruction of a barn and damage to other out buildings. Heavy rains led to widespread record (black) and near record (dark blue) river flows in Missouri, Illinois, Indiana, and Kentucky (Figure 9, U.S. Geological Survey), with some minor flooding in places.
The eastern Midwest experienced several days of light rain and showers as several impulses moved northward along the upper level wave that was slowly shifting across the region. The rain was not heavy enough to disrupt federal elections on the 2nd, but probably reduced the comfort level considerably for people who stood in line outdoors. The most significant impact of the rain was to keep farmers out of the field who were still waiting to finish the fall harvest or prepare fields for spring. The second surface low pressure center finally pulled away on the 4th (Figure 10, COD), leaving behind cooler and very windy conditions (Figure 11, COD).
Solar Flares Bring Colorful Northern Lights to the Midwest
On the 4th, a major solar flare erupted towards the Earth (Figure 12, NOAA), spewing radiation and large numbers of charged particles which were intercepted by the upper atmosphere. A major aurora display reached to the southernmost edge of the Midwest in Missouri and Kentucky (Figure 13, NOAA). All locations that were cloud free were able to observe the northern lights in a multitude of colors and shapes. In the northern Great Lakes, though, it was cloudy, as the cold air and northerly flow brought on an outbreak of lake effect snow in the eastern UP of Michigan and northern Lower Michigan. Snow fall totals of up to 3 inches were noted in the region. The lake effect continued very lightly on and off for several days. Finally, a strong cold front followed by a Canadian high settled into the region on the 8th, bring some of the coldest temperatures of the fall so far across the entire Midwest during the following morning (Figure 5). While the minimum temperatures on the 9th were only 5-10°F below normal, it is apparent that winter cannot be too far away.