August 2009 Climate Summary

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

Region Breakdown

A persistent upper air pattern continued to keep the High Plains Region cool this August.  Most locations had average monthly temperatures that were 2˚F to 4˚F (1.1˚C to 2.2˚C) below normal and isolated areas of the Region were 4˚F to 8˚F (2.2˚C to 4.4˚C) below normal.  Monte Vista, CO recorded its coolest August with an average temperature of 57.8˚F (14.3˚C), which broke the old record of 58.2˚F (14.6˚C) recorded in 1956.  Interestingly, many locations recorded average temperatures that were nearly identical to those recorded in July.  For instance, Lincoln, NE had an average temperature of 72.6 (22.6˚C) in July and 72.3 (22.4˚C) in August.  Lincoln’s normals for July and August are 77.8 (25.4˚C) and 75.4 (24.1˚C), respectively. 

For the summer, temperature departures of 2˚F to 5˚F (1.1˚C to 2.8˚C) below normal dominated the Region and many locations ranked in the top 15 coolest summers on record.  The only exceptions to the mild weather were isolated pockets of Wyoming, Colorado, and Kansas.  Casper, WY recorded its coolest summer with an average temperature of 63.9˚F (17.7˚C).  The previous record of 64.3˚F (17.9˚C) occurred in 2004.  More information about summer 2009 temperature rankings is located on page 5 of the climate summary.

Precipitation Summary

This August, some areas of the Region received ample precipitation, while other areas were dry and saw either the development of abnormally dry conditions or little relief to ongoing drought.  Precipitation totals exceeding 200% of normal were confined to pockets of Wyoming, South Dakota, Nebraska, and Kansas.  Within these regions of heavy precipitation, many locations recorded the wettest August on record (see table below).  The driest areas in the region were Colorado and North Dakota where precipitation totals less than 50% of normal were common.

This month’s wet spot is Columbia, SD.  Not only did this location record its wettest August, it also recorded its wettest summer.  Columbia received 7.22 inches (183.4 mm) of precipitation, or 313% of normal, this month which smashed the old record of 5.84 inches (148.3 mm) recorded in 1957.  For the summer, Columbia received 17.90 inches (454.7 mm) of precipitation which is 9.45 inches (240.0 mm) above normal and 212% above normal.  The old record of 14.45 inches (367.0 mm) was recorded in 1993.

Climate Outlook

El Niño conditions continued this month and, based on observations and forecasts, will strengthen and continue through winter 2009-10.  The temperature outlook indicates a higher probability of above normal temperatures for the majority of Colorado, a small portion of southern Wyoming, and far eastern Kansas.  Elsewhere in the region, equal chances of above, near, or below normal temperatures are predicted.  The precipitation outlook indicates a higher probability of above normal precipitation for a broad area that includes the western halves of South Dakota, Nebraska, and Kansas, eastern Wyoming, and the eastern half of Colorado.  Elsewhere in the region, equal chances of above, near, or below normal precipitation is predicted.  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.

Drought Watch

The two areas of moderate drought (D1) remain largely unchanged this month as drought persists in eastern North Dakota and southeastern Nebraska.  Both areas have seen crop stress however, impacts should be only short term as streamflows are above normal and the long term outlook is good.  Due to a weak monsoon season, abnormally dry conditions (D0) have developed in southwest Colorado.  Elsewhere in the Region, only minor changes were observed in the U.S. Drought Monitor.  According to the U.S. Seasonal Drought Outlook, the drought conditions in south central Nebraska and east central North Dakota are expected to improve through November 2009.