Outlook for Fall – Warm and Dry

NOAA’s Climate Prediction Center issued new outlooks today for October and beyond. The latest outlook for October shows all of Illinois having increased chances of being both warmer and drier than normal.
BTW, this is the exact opposite of how last October turned out. The statewide precipitation total in October 2009 was 8.40 inches. That was 5.5 inches above normal and the 2nd wettest October on record. The statewide average temperature was 49.6 degrees. That was 4.6 degrees below normal and the 6th coldest on record.
The outlook for October-December shows all of Illinois having an increased chance of warmer than normal conditions. Precipitation has “equal chances” of being above, below, and near-normal, or what I call a neutral forecast.

NOAA CPC forecast for this fall. Click to enlarge.

La Nina Returns

The NOAA Climate Prediction Center (CPC) noted earlier this month that “La Niña conditions are expected to strengthen and last through the Northern Hemisphere winter 2010-11.” A La Niña occurs when abnormally cold waters develop along the equator of the central and eastern Pacific Ocean. These changes in the ocean and atmosphere in turn influence the weather over the United States.
That feature is incorporated into the seasonal outlooks provided by the CPC. Right now they are calling for an increased chance of above normal temperatures this fall (September-November) across Illinois. Precipitation has an increased chance of being below normal in the southern two-thirds of Illinois.

Fall outlook.
Outlook for fall for 2010, NOAA Climate Prediction Center.

For this winter (December-February), they call for an increased chance of above normal temperatures in the southern half of Illinois, with equal chances of above, below and near normal temperatures in the northern half of Illinois.  They do call for an increased chance of above normal precipitation across all of Illinois and much of the Ohio River Valley. Updated official seasonal forecasts are posted mid-month here.