WEST LAFAYETTE, Ind. – Weather spring has arrived, with forecasts from the Climate Prediction Center (CPC) covering March, April and May. The vernal equinox, traditionally celebrated as the start of the season, will take place on March 20. There are currently strong La Nina conditions prevailing with a below average temperature of more than one degree Celsius in the equatorial region of the Pacific. These conditions have some impact on the outlook.
The Nina currently affecting Indiana is relatively strong, but is expected to weaken in the spring with El Nino – Southern Oscillation (ENSO) neutral conditions prevailing by summer. The model predicts a chance to return to La Nina by fall. A traditional winter / early spring La Nina puts Indiana at risk for above average precipitation. The CPC predicts that Indiana has a greater than 40% chance of experiencing wetter than average conditions (compared to drier than normal or normal conditions).
Beth Hall, a state of Indiana climatologist, said, “This winter has started off fairly mild, which is not unusual for La Nina winters. We expected the winter to end with more wintry conditions – especially regarding unusually cold and snowy conditions. It’s always a relief when these predictions seem to come true as we saw last February!
The forecast indicates that most will receive about half an inch of above average precipitation over the next three months. This would be welcome news for the north and northeast of the state, where abnormally dry and moderate drought conditions have persisted since last fall.
Sources from La Nina tend to have a warming signal in the southern United States, while a lesser signal exists for the northern parts of the continent. Meanwhile, the general trend towards warm springs in recent years has been moderately predictable. The CPC has listed most countries with above normal temperature probabilities, including all of Indiana. On average over the period, however, temperatures in Indiana are only expected to be 0.5 degrees Fahrenheit higher than average.
Spring brings back humidity, warmer temperatures and a greater likelihood of severe weather. The conditions of La Nina were studied with correlations to hailstorms and tornadoes. Spring conditions in La Nina increase the likelihood of hailstorms throughout the state of Indiana. The probability of a tornado is only slightly increased in southern Indiana. The odds increase in the Oklahoma / Arkansas area, but decrease more from this epicenter.
To analyze the spring forecast, most of the information in this article resides here. Severe weather reference is available here or in the Journal Nature Geoscience, published in April 2015 and written by Allen, Tippett and Sobel.
For more information on the seasonal outlook, contact Hans Schmitz at the Purdue Extension Posey County office via [email protected] or 812-838-1331, or the Indiana State Climate Office at 765-494-8060.
Sources: Beth Room, 765-494-8060, [email protected]
Hans Schmitz, 812-838-1331, [email protected]
Agricultural communications: 765-494-8415;
Maureen Manier, Head of Department, [email protected]