Drought Expands in Illinois

The U.S. Drought Monitor released the latest drought map, showing that the “severe” D2 drought has expanded across much of northern Illinois. Only an area in the northeast part of the state remains in moderate drought (first figure).
The Climate Prediction Center also released their drought outlook today. They expect the drought in the central U.S. to persist over the next 3 months (second figure).

U.S. Drought Monitor map for Illinois, released on July 19, 2012. Click to enlarge.

Climate Prediction Center drought outlook, released on July 19, 2012. Click to enlarge.

Monthly Temperature and Precipitation Departures Since 2011 in Illinois

Here are the statewide Illinois monthly temperature and precipitation departures from the 1981-2010 average for both 2011 and 2012. We have had a run of above-average temperatures since October 2011 and a run of below-average precipitation since January of 2012. The latest outlooks published on June 30 by the National Weather Service shows that the odds of this pattern of warmer and drier conditions to prevail through July (bottom figure).

Statewide temperature departures (F) from the 1981-2010 average in Illinois for 2011 and 2012. Red is warmer than average. Blue is cooler than average. Click to enlarge.

Statewide precipitation departures (F) from the 1981-2010 average in Illinois for 2011 and 2012. Blue is wetter than average. Yellow is drier than average. Click to enlarge.

Outlooks for July and July-September as provided by the National Weather Service. Click to enlarge.

Latest Seasonal Outlook

NOAA’s Climate Prediction Center released their June and June-August outlook yesterday (figure below). On the left hand side of the figure, they have far southern Illinois with an increased chance of above normal temperatures for June. For June-August, that area of increased chances expands and covers an area roughly south of I-70.  The rest of the state has “EC” or equal chances of above, below, or near-normal temperatures. In other words, they don’t see anything to push temperatures one way or another.
It’s the same story with precipitation – equal chances of above, below, or near-normal precipitation across the state for June and June-August. I think its fair to say that our current skill is pretty low in forecasting summer-time precipitation months in advance.

NOAA’s Climate Prediction Center outlook for this summer. Click to enlarge.

Forecast for This Summer in Illinois

The Climate Prediction Center (NOAA) just released their outlook for July as well as July-August-September. In their own words, Illinois has equal chances (EC) of above-, below-, or near-average temperatures and precipitation for this summer. It’s what I would call a “neutral forecast” for us.
On the other hand, the Northern Plains are expected to be cooler and wetter than average for both July and July-September. Meanwhile, much of the South is expected to be warmer than average this summer.
One factor that will not dominate this summer is La Nina. Sea surface temperatures in the Pacific along the equator have returned to neutral conditions and will remain so at least through this summer.

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The July and July-September outlooks from the Climate Prediction Center, NOAA. Click to enlarge.