March 2000
Temperature and Precipitation Anomalies.
After a brief seasonably wet period in February, the Midwest returned to the pattern of well below normal precipitation that started in July 1999 (Figure 1). Each of the nine states in the region averaged below normal in precipitation. Only a narrow band at the northern edge of Minnesota, Wisconsin, and Michigan had normal to above normal precipitation levels; most of this precipitation fell between March 8 and 10. On the other hand, a wide axis through Iowa, northern Illinois, and lower Michigan recorded less than 50% of normal precipitation. This was the 23rd driest March in 106 years in the Midwest. The Corn Belt experienced no relief from intensifying drought conditions.
Temperatures were above normal throughout the entire Midwest, with Minnesota, Wisconsin, and Iowa temperatures ranking 4th or 5th warmest in March observational history (Figure 2). All three states averaged more than 8F above normal, with some border regions near Canada averaging 10-12F above normal. Temperatures were strongly above normal during the first and last 10 days of the month, with only mid-March temperatures bracketing the normal range. The Midwest average temperature in March ranked 6th highest in 106 years. Starting with the first drought month, July 1999 to March 2000 is the second warmest July to March period on record.
The month of March was very quiet from a winter weather or severe weather perspective in the Midwest. Only one notable snow storm affected the area on March 11-12 (Figure 3). An intense low pressure center moving through the northern Gulf states produced a large precipitation shield in below freezing air over southern Illinois, Indiana, and Ohio. One location in southeastern Illinois reported 13 inches of snow, while a number of places in Illinois and Indiana had 8-10 inches of snow. Besides disrupting travel for a day, impacts were minimal, as the snow melted quickly afterward.
On March 26 there was an appreciable outbreak of severe weather in Missouri, extending into extreme southern Illinois (Figure 4, from the Storm Prediction Center). About 67 severe hail reports and 29 severe wind reports were received by the Storm Prediction Center, but no tornadoes were noted. Local power outages resulted from downed power lines; however, no injuries were reported.
Agricultural concerns intensified as precipitation totals fell well below normal over most of the Corn Belt. Much of Kentucky, Illinois and Iowa would require 3-5 inches of excess precipitation above normal in the next month or two to bring Palmer drought indices into the low end of the normal range, while much of central and northern Indiana and Ohio would require 5-6 inches. In addition, drought seems to be spreading into all of Lower Michigan. The total precipitation deficit since July 1, 1999, reaches 6 to 12 inches throughout the Corn Belt (Figure 5).
In Illinois, where direct measurements of soil moisture are available, the topsoil is beginning to dry again following its recharge during the wet month of February. The subsoil layers remain in an extremely dry state, with central Illinois soil moisture levels less than 50% of normal from 20 to 72 inches below the surface. The SC of Illinois, Jim Angel, calculates that there is less than a 50% chance of any recovery of soil moisture to more normal levels, based on the statistics of years with similarly dry late summer to spring periods. In addition, long term forecasts from NOAA are also pessimistic. The MRCC will be monitoring the developing drought and its impacts closely.