September 2009 Climate Summary

For a printable version of the climate summary which includes more figures, data tables, and state summaries, click here. 

Region Breakdown

Temperature departures varied widely this September as average temperatures generally ranged from 8˚F (4.4˚C) below normal in the southern portions of the Region to 10˚F (5.5˚C) above normal in the northern portions of the Region.  The warm temperatures in the north helped farmers in their harvesting efforts.  According to the USDA, the warm temperatures in the north aided small grain harvest and also helped the maturity of late season crops.  

Many locations in North Dakota had average temperatures which ranked in the top 10 warmest Septembers on record.  The warm temperatures broke two longstanding records, one of which had been in place in Grand Forks, ND since 1906.  The average temperature this month for Grand Forks was 64.2˚F (17.9˚C) which broke the old record of 62.8˚F (17.1˚C).  Williston, ND also had its warmest September on record.  The old record of 64.0˚F (17.8˚C) was just barely edged out by the new record of 64.3˚F (17.9˚C).  A more thorough list of records is located on page 2.

Precipitation Summary

September 2009 was drier than normal for most of the Region as precipitation departures of 1.50 inches (38.10 mm) below normal were common.  Areas of the Region that received more than 200% of normal were isolated to a swath of Kansas and pockets of North Dakota, South Dakota, and Colorado.  The rain that fell in North Dakota helped alleviate drought conditions in the east central portion of the state as moderate drought conditions have been downgraded to abnormally dry conditions.

This month’s wet spot was Oakley 4 W, KS which received 7.81 inches (198.37 mm) of precipitation.  This record breaking amount was 6.47 inches (164.34 mm) above normal, or 583% of normal.  The old record of 6.20 inches (157.48 mm) was recorded in 1976.  On September 8th, 4.81 inches (122.17 mm) fell breaking the previous record of 2.83 inches (71.88 mm), which occurred in 1935.  This rainfall was part of a heavy rain event that occurred in western Kansas and eastern Colorado on the 7th and 8th of September.  The heavy rains in the area resulted in rises on creeks and streams and, according to the NWS in Goodland, KS several homes were inundated along the south fork of the Saline River, just north of Oakley.

Climate Outlook

El Niño conditions are present and will intensify and continue through winter 2009-10 based on current observations and forecasts.  The temperature outlook indicates a higher probability of above normal temperatures for the whole region except for the eastern half of Kansas where equal chances of above, near, or below normal temperatures are predicted.  The precipitation outlook indicates that there are equal chances of above, near, or below normal precipitation for the entire region.  The seasonal outlooks combine the effects of long-term trends, soil moisture, and, when applicable the El Niño Southern Oscillation (ENSO) cycle.  More information about these forecasts can be found here: http://www.cpc.ncep.noaa.gov/.

Drought Watch

Despite lower than normal precipitation in many locations, much of the Region remained drought free this September.  Moderate rains in the middle of the month allowed for the elimination of moderate drought conditions (D1) in east central North Dakota.  Abnormally dry conditions (D0) are present in a small portion of south central Nebraska, eastern South Dakota, and east central and western North Dakota.  However, in southwest Colorado, the Animas and Los Pinos Rivers are flowing below normal and the Lemon Reservoir is 25% full, which places that area into D1.  According to the U.S. Seasonal Drought Outlook released September 17, the drought conditions in east central North Dakota are expected to improve through December 2009.