PLEASANT WEATHER?: PHENOMENON CALLED EL NINO HAS GIVEN MILD TEMPERATURES

If you've enjoyed the relatively mild weather so far this winter in the Cape Girardeau area, give thanks to El Nino.

El Nino is a weather phenomenon affecting not only our local weather but weather worldwide, said Dr. Al Robertson, professor of earth science and climatologist at Southeast Missouri State University.

"El Nino is a local name for a change in the circulation and temperature of the waters of the Pacific Ocean off the west coast of South America," Robertson explained. "El Nino occurs every few years, and when it does it has a major impact on global weather.

"During the past several months, the warming trend in the ocean water has raised the air temperature in the atmosphere above the ocean, The change in air temperature has caused major shifts in the polar and sub-tropical jet streams, which help create and steer weather systems and air masses in the United States."

Robertson said the impact of El Nino this winter has caused the polar jet stream, which usually dips deep into the United States at this time of the year, to stay well to the north, along the Canadian border.

Robertson said the polar jet stream triggers the frequent and sometimes prolonged outbreaks of frigid arctic air that plunge deep into the middle United States in January and early February.

Instead, the warming of the atmosphere by El Nino has allowed the sub-tropical jet stream that normally remains over the Gulf of Mexico at this time of year to push farther northward, at times over Missouri and Illinois. Areas near to and south of the sub-tropical jet stream have enjoyed generally mild weather and temperatures.

An example of this was Monday, when the afternoon high soared to 69 degrees, 1 degree short of tying the record high for the date, set in 1962, and nearly 30 degrees above normal. Temperatures are now back to just slightly above early February normals.

How long El Nino will last is a question that has puzzled climatologists since it was first discovered. However, the National Weather Service's 30- and 90-day weather outlooks indicate no significant shifts in local weather patterns through the end of April.

Both the 30- and 90-day outlooks indicate near normal temperatures and normal amounts of precipitation are expected through the end of April.

Meanwhile, El Nino's impact is seen in the January temperature average, Robertson said. "The actual January temperature average was 37.4 degrees," he said. "That was up nearly 5 (4.7) degrees from the long-term average of 32.7 degrees."

The high last month was 62 on Jan. 30. There were six days when the afternoon high was in the 50s, and only four days when it was below freezing, Robertson said.

"There were only 18 mornings when the low was below 32 degrees, which is a little unusual considering January is the coldest month of the year here," Robertson said.

January started out warm. It turned cold during the middle of the month and warmed up again during the final third of the month, said Robertson.

The January 10-day averages were:

Jan. 1-10, average of 41.7 degrees, up 9 degrees from the long-term average of 32.7.

Jan. 11-20, average of 30.7, down 1.7 degrees from the long-term average of 32.4 degrees.

Jan. 21-31, average of 39.7 degrees, up 6.4 degrees from the long-term average of 33.3 degrees.

"We only had two real bad days last month, on the 15th, when the morning low was 13 degrees, and on the 16th, when it was 10 degrees," said Robertson. "That was the coldest day of the month," he said.

Precipitation last month was also below normal, but Robertson said the lack of moisture is not disturbing. "Everywhere you look there is water standing in farm fields and ditches north and south of Cape Girardeau," he said. "We don't need any more precipitation right now."

Robertson said actual precipitation at the airport last month was 2.37 inches, down 1.15 inches from the long-term average of 3.52 inches.

"There were only seven rainy days last month, and nearly all of them came during the first half of the month," Robertson said. "The only precipitation after Jan. 16 was .10 of an inch that fell on Jan. 22."

Two inches of snow was recorded last month. The airport normally receives 3.5 inches in January.

The long-term average temperature for February is 37.4 degrees. Last year it was 41.2 degrees, up 3.8 degrees.

Long-term average precipitation for February is 2.84 inches. Last year the average was 2.69 inches.

Average snowfall in February is 3.4 inches. February will always be remembered in Cape Girardeau County as the anniversary of the 1979 blizzard that buried parts of Southeast Missouri and Southern Illinois under 24 inches of snow during the last week of the month.