outlook – Illinois State Climatologist

April 16, 2015

NWS Outlook for the Growing Season in Illinois

The NOAA Climate Prediction Center has released their monthly and seasonal outlooks for the growing season.

In the near-future, the 6-10 and 8-14 day forecast indicate that colder-than-average conditions will prevail for the next two weeks. For precipitation, there is an increased chance of drier-than-average conditions in parts of northern Illinois for the next two weeks.

There is not a lot to report for Illinois at the medium range. We are in equal chances (EC) for above-, below-, and near-average temperature and precipitation for both May and the 3-month period of May-July.

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October 16, 2014

NWS Outlook for November and Winter

Today the NWS Climate Prediction Center has released their latest outlook for November and this winter. Below are the maps for November temperature, November precipitation, December-February temperature, and December-February precipitation.

For Illinois, November temperatures have equal chances (EC) of being above, below, or near-average. November precipitation is rated as EC except for the northeast quarter of the state, which has an increased chance of below-average precipitation. This is part of a larger area with increased chances of below-average precipitation across the Great Lakes region.

The category of EC is a little hard to interpret. Basically, it means that there are no consistent indications that conditions could be too warm/cold/wet/dry. Sometimes I call it a neutral forecast.

For December-February, the traditional winter months, Illinois has equal chances (EC) of above, below, and near-average temperatures. However, Illinois has an increased chance of below-average precipitation.

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October 29, 2012

NOAA Winter Forecast

Back on October 18, NOAA released their winter forecast. There was nothing too exciting for Illinois. Illinois has equal chances of above, below, and near-normal temperatures. The same is true for precipitation, except along the westward edge of Illinois which has a slightly increased risk of below-normal precipitation. See maps below.
If you look at the past dozen years in Illinois, winter-time temperatures have been consistent at being inconsistent (see graph). We have had some really mild winters in 2001-2002 and this last winter. On the other hand, we have had harsh winters including the three before this last winter.
Just to give you an idea of what is “normal” or average about Illinois, here is the link to the monthly and seasonal precipitation, temperature, and snowfall across Illinois.

winter-temp — Winter temperatures in Illinois for past 12 years. The departure is from the 1971-2000 period. The double date represents December of the first year and January and February of the second year.

Outlook_map_Precip_2b — NWS Winter Precipitation Outlook.

September 20, 2012

A Warm Fall for Illinois?

NOAA’s Climate Prediction Center released their latest monthly and seasonal outlooks today (Thursday). In the figure below, the outlook for October in Illinois is for an increased risk of above-normal temperatures and below-normal precipitation. The 3-month outlook for October-December in Illinois is for an increased risk of above-normal temperatures. Their precipitation outlook is neutral at this time.
That’s not the best news for drought recovery but it might make it easier on farmers for fall harvest.
One factor that could come into play this winter is El Niño. In fact, the CPC says an El Niño event is likely to arrive some time in September, according to their latest advisory. However, in the last two winters the Arctic Oscillation has played a major role in our winter weather. Two winters ago it was in the negative phase and dumped lots of cold air into Illinois. Last winter it was in the positive phase and prevented a lot of cold air from reaching us. Unfortunately, we can only forecast the Arctic Oscillation out to 14 days.