WEST LAFAYETTE, Ind. — The lack of a developing, dominant
weather system coupled with erratic changes over the past year indicate that
Indiana could be in for wide swings in weather in the early weeks of autumn, the
State Climate Office said.
The October outlook is for above-normal temperatures with
equal chances for above-normal, normal and below-normal precipitation.
Weather beyond October is more difficult to assess because
climatological systems such as El Niño and La Niña that would drive Indiana
weather into November still are evolving.
“This is a time when we should be cautious about looking too
far into the future, especially when we don’t have a dominant driver,” said Dev
Niyogi, state climatologist based at Purdue University.
“There are some years when we have very strong indicators.
When El Niño and La Niña are active, they tend to dictate the weather of our
upcoming season, and we can project with higher confidence whether it will be
warmer or drier.”
The fall season will be influenced by multiple air masses,
any of which could dominate at any time, Niyogi said.
“If we have a tropical atmosphere becoming more active, then
we can expect more warmer and humid weather conditions, with more storm
activity,” he said. “On the other hand, if that is not the dominant factor, then
we might have the potential for a colder, drier air mass coming to Indiana more
Which pattern might develop as the stronger of the two is in
question at this time.
“And therein lies our dilemma at this point in drawing one
strong, singular conclusion as to what will dominate,” Niyogi said. “But one
thing that we can say for certain is in the absence of one strong driver and
that we will be influenced by multiple air masses, it is very likely that
Indiana will witness wide swings in its week-by-week weather as we go into the
Adding to the difficulty in forecasting is the unusual
weather Indiana has experienced in the past couple of years, especially since
last year when drought was so severe that it led to fire and watering bans and
drastically lowered crop yields.
Indiana emerged from drought over the winter with frequent
precipitation, which was followed by an abundance of spring rain that delayed
many farmers in planting their crops.
Then, in another turnabout, Indiana this summer again fell
into an extended dry period that brought back drought to some areas and lowered
high expectations for excellent crop yields.
The U.S. Drought Monitor update of Sept. 26 showed that
heavy rains the previous week brought some relief to Indiana.
Several counties in the state’s midsection that had been in
moderate drought — the lowest level of drought — improved to abnormally dry.
Some other counties got enough rain to eliminate dry conditions.
Niyogi said the climate office will continue to monitor the
situation to determine whether any particular weather driver seems to become
dominant. The office will provide an updated outlook later in the fall.
Ken Scheeringa, associate state climatologist, said autumn
typically is a difficult time for forecasting because the state is transitioning
from the summer to weather patterns that will establish themselves for the
“Sometimes there is a very sharp cutoff between seasons, but
that’s not happening,” he said.
One thing about the fall that Scheeringa could say with
absolute certainty — and with tongue in cheek: “Autumn arrived at 4:44 p.m. EDT
on Sept. 22, exactly as predicted well in advance.”