FALL: FOLIAGE PROSPECTS PROMISING

Autumn arrived Tuesday, bringing an end to the fifth coolest summer here in 47 years and the prospects of a colorful fall.

According to the Old Farmer's Almanac, the autumnal equinox occurred at 2:43 p.m. That's when the sun crossed Earth's equator, from the northern hemisphere to the southern hemisphere. It also marked the first day of spring in the southern hemisphere.

It's called the autumnal equinox because the number of hours of daylight and darkness for several days before and after Sept. 22 are nearly equal at 12 hours.

Charles Korns, professor of horticulture at Southeast Missouri State University, said the leaves of most trees in the area are healthy because of the unseasonably cool, wet summer.

"What's needed now are bright, sunny days, and cool, clear nights to start the coloring process," Korns said.

That could be right around the corner. The National Weather Service's short- and long-range outlooks call for cooler than normal temperatures in Southeast Missouri and Southern Illinois.

The 6-10 day outlook indicates cooler than normal temperatures in the area and much cooler weather east of the Mississippi River.

The 90-day outlook calls for below normal temperatures through most of the Midwest. Precipitation during the same period is expected to average near to above normal.

Korns said some leaves north of Cape Girardeau are already starting to turn colors. "I've read that in the upper part of the country, in northern Illinois, Wisconsin, Minnesota and Michigan, the trees started turning colors in mid-August because of the very cool weather this summer," he said.

The first day of fall ends what Southeast Missouri State University climatologist Al Robertson classified as the fifth coolest summer in 47 years at Cape Girardeau. Robertson said last month was also the third coolest August on record in the same time period.

Robertson explained for purposes of statistical record-keeping climatologists and meteorologists have divided the four seasons into quarters of about 90-days each.

"It was certainly a very unusual summer," he said. "The average temperature for the 92-day period (June 1-Aug. 31) was 75.7 degrees, compared to the long-term average of 77.6 degrees, or a decline of 1.9 degrees from the long-term average."

By comparison, the coolest summer here was in 1967, with an average of 74.6 degrees. The hottest summer here was in 1980, with an average of 80.9 degrees

Robertson said there were only 24 days this past summer when the daily high was between 90 and 95 degrees. It did not reach 100 degrees this summer. The hottest day of summer was only 95, on June 17.

"That's also very unusual," Robertson said. "For example, in the summer of 1967, which included the coolest June on record, we still had 26 days when the temperature was above 90. This year we had 24. In contrast, our hottest summer on record was in 1980, when there were 55 days when the temperature was above 90 degrees, plus 10 days when the daily high was in the 100s."

Robertson said last month was the third coolest August on record, with an average temperature of 73.6 degrees, down 3.8 degrees from the long-term average of 77.4. August weather was highlighted by two record low temperatures on Aug. 16-17. The low of 52 on Aug. 16 broke the record of 53, set in 1963. The following morning, the low of 57 broke the record of 59 set in 1962, and tied in 1964 and 1979.

Robertson attributed the unusually cool summer to the eruption last year of Mount Pinatubo in the Philippines and erratic movement of the jet stream that guides air masses and weather-making storms in the upper stratosphere.

"The eruption of the volcano has put a lot of ash and dust in the upper stratosphere that's cut down on the amount of sunlight filtering down onto the ocean and the land surface. That has a direct impact on our weather," he explained.

During most of the summer, the polar jet was not as far north as it usually is, and that allowed cooler air from Canada to come down more frequently during the summer months, said Robertson. On the other hand, the sub-tropical jet stream remained farther south along the lower Gulf Coast states, holding back the normal advances of warm, humid Gulf air expected in mid- and late-summer, he said.

"As a result, we spent most of the summer situated between the split jet streams," he said. "It was an unusual summer, but I didn't hear many complaints from people about the absence of hot, humid weather. There were some concerns about crops maturing in time before the first freeze, but the warmer weather this month should have them ready in time."

Rain this summer was slightly below average, 9.58 inches, compared to the long-term of 10.74 inches.

For the year through Aug. 31, precipitation at the airport totaled 23.17 inches compared to the long-term average of 30.79 inches, or a decline of 7.6 inches. But Robertson said 4.88 inches fell at the airport during the first 20 days of September. That compares with the total long-term monthly average of 3.62 inches.