In an earlier post we examined the NWS Climate Prediction Center forecasts through next summer that included the statement, “Illinois has a higher risk of being both warmer and drier than average through mid-summer. There is an increased risk of being warmer than average in late summer and in fall.”
Taken at face value, the NWS forecast would suggest that we have an increased risk of drought this year. Six months of warmer and drier weather can certainly do that.
However, the key factors in this forecast will be how the El Niño winds down and if La Niña shows up. The chart below is the forecast showing the odds for how things may play out in 2016. The red bar represents the odds of El Niño. The odds are now at 100% and slowly decreased for the next several 3-month time frames. By May-June-July (MJJ), there is only a 40 percent that El Niño will still be around. At that same time, there is an almost 50 percent chance that we will return to average or “neutral” conditions (green bar).
In the meantime, there is a small, but increasing chance that La Niña could appear (blue bar) and the odds reach 40 percent in August-September-October. Take my word for it, you don’t want La Niña showing up. In Illinois we have a pattern of warmer and drier conditions in the critical July-August time frame during La Niña. A return to neutral conditions is more favorable with near-average conditions in July and August.
Another thing to consider is that El Niño and La Niña are not the only two players in town. Indeed, other weather patterns can overwhelm the influence of these two. For example, we have had several springs in recent years with short periods of a very active storm pattern, resulting in very wet conditions.