If it seemed spring was a lot cooler than normal, that's because it was. And you can again blame it on El Nino and Mount Pinatubo.
The months of March, April and May were the eighth coolest in 46 years in Cape Girardeau, said Al Robertson, climatologist and professor of geo-sciences at Southeast Missouri State University.
The unusually cool spring continues an abnormal weather trend that began two years ago. Last summer was the fifth coolest summer in 46 years in Cape Girardeau; the past winter was also mild.
Robertson said the actual average temperature for the 90-day period was 55.1 degrees, down 2.1 degrees from the long-term average of 57.7. "For that time period, it's a significant decrease from the norm," he said.
Although it seemed like it was also a wet spring, Robertson said it actually was drier than normal. Precipitation for the three-month period was 12.29 inches, 1.29 inches below the long-term average of 13.58.
Robertson said it seemed wetter than it was because of the number of cloudy days. He said the extensive cloud cover hid the sun, which prevented evaporation of surface water that accumulated in low spots during January and February.
"Another reason it seemed like it was wetter than normal was the number of days when we got less than a tenth of an inch of rain," Robertson said.
He said January and February are the wettest months so far this year, with 5.21 inches in January, compared to a long-term 3.52 inches; and 3.54 inches in February, compared to 2.84 inches long-term.
On the other hand, precipitation for March, April and May was at or below normal. During March, 3.55 inches was measured at the airport, compared to the long-term 4.41 inches. In April only 3.68 inches fell, compared to the long-term 4.47 inches. May's total precipitation was 5.06 inches, up .32 of an inch from the long-term average of 4.74 inches.
For the period Jan. 1 through May 31, total precipitation at the airport totals 21.04 inches, up 1.06 inches from the long-term average of 19.98 inches.
Robertson and other climatologists attribute the unusually mild winter and cool spring to the El Nino effect and the eruption of Mount Pinatubo in the Philippines. El Nino is named for the unusual warming of the waters of the Pacific Ocean, which has caused major shifts in the movement of the jet stream. In addition, the millions of tons of volcanic dust and debris that was shot into the stratosphere during the eruption of Pinatubo is also thought to have had a major influence on global weather patterns, including the United States during the past two-and-one-half years.
Robertson said the impact on weather caused by the volcanic eruption is decreasing as the dust slowly settles back to Earth. However, he said there are indications El Nino is strengthening once again in the Pacific. If that happens, he said Southeast Missouri and Southern Illinois could be in for another cool and wet summer.
Robertson said May started warm, then cooled dramatically toward mid-month, only to warm again toward the end of the month. The 10-day averages: May 1-10, 69.4 degrees, 5.6 degrees above the long-term average of 63.8; May 11-20, 62.1 degrees, down 5 degrees from the long-term average of 67.1; and May 21-31, 68.2 degrees, down 2.2 degrees from the long-term 70.4.
The average temperature for May was 66.6 degrees, slightly below the seasonal norm. Robertson said the May average would have been even lower had it not been for a string of 80-degree-plus days that occurred between May 22 and May 31. The high for the month, 91 degrees, occurred May 28; the low was 46 on May 14.
June got off to an unusually cold start. The overnight low on June 1 dropped to 45 degrees, only 3 degrees above the record low for the date. But temperatures were expected to rebound into the upper 80s by the end of the week.
The National Weather Service's 30-day outlook for June for the area calls for near- to slightly-below-normal temperatures and above-normal precipitation. The 90-day outlook for the summer months of June, July and August is for near seasonal temperatures and precipitation.
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