July 2010 Climate Summary

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

Temperature Summary

July 2010 was an active month for the High Plains Region.  In addition to a new United States hail record which was set in South Dakota, numerous daily and monthly precipitation records were set across Colorado, Kansas, Nebraska, and South Dakota (for more details and photos see page 2 of the climate summary).  Temperatures across the Region, on the other hand, were near normal with temperature departures ranging from 2 degrees F (1.1 degrees C) below normal to 2 degrees F (1.1 degrees C) above normal.  Some areas of Colorado and a few other locations scattered through the Region were 2-4 degrees F (1.1-2.2 degrees C) above normal.

While most locations were near normal, one location made it into the top 10 warmest Julys on record.  Crested Butte, Colorado, which is located in the west central part of the state, tied for its 4th warmest July.  The average temperature in Crested Butte was 60.4 degrees F (15.8 degrees C) which was 4.4 degrees F (2.4 degrees C) above normal.  This was close to, but could not beat out the warmest July on record which occurred in 1966 with an average temperature of 61.0 degrees F (16.1 degrees C) (period of record 1910-2010).

Precipitation Summary

July 2010 was a wet month for portions of Colorado, Kansas, Nebraska, and South Dakota.  Southeastern South Dakota and northeastern Nebraska, where precipitation was 200-300 percent of normal, were hit particularly hard and flooding along many rivers continued into August.  The abundance of moisture this month led numerous locations to be ranked in the top 10 wettest Julys on record and at least 5 of these locations recorded their wettest July. 

Within the first week of July locations in Kansas, Colorado, and Nebraska were already ranked in the top 10 wettest Julys on record.  Heavy rain in the panhandle of Nebraska caused flooding and evacuations in the town of Lodgepole.  Dodge City, Kansas set a new record for the greatest 24-hour precipitation when 6.95 inches (176.53 mm) of precipitation fell in less than 24 hours on July 4-5.  Dodge City went on to record its second wettest July with 8.40 inches (213.36 mm) of precipitation.  This total was just shy of the record 9.13 inches (231.90 mm) which fell in 1962 (period of record 1875-2010).  July 23rd was an active day in South Dakota.  Storms produced high winds, flooding, tornadoes and record breaking hail.  According to the National Weather Service in Aberdeen, South Dakota, a record breaking hailstone fell in Vivian, South Dakota that measured 8 inches in diameter, weighed 1.9375 pounds, and had a circumference of 18.62 inches.  The previous record hailstone, by weight, fell in Coffeyville, Kansas September 3, 1970 and weighed 1.67 pounds.  The previous record hailstone, by diameter, was the 7 inch Aurora, Nebraska hailstone which fell June 22, 2003.  The Aurora hailstone retains the record for largest circumference at 18.75 inches.  Later in the month, due abundant monsoonal moisture, the Trinidad Perry Stokes Airport, Colorado recorded its wettest July with 6.84 inches (173.74 mm) of precipitation.  This beat out the old record of 6.55 inches (166.37 mm) received in 1981 (period of record 1948-2010).  Interestingly, earlier this year this location also recorded its wettest February and wettest March.  Through July 31st, the year-to-date precipitation total at the Trinidad Perry Stokes Airport was 16.51 inches (419.35 mm), which makes 2010 already the 10th wettest year on record. 

Climate Outlook

As negative sea surface temperature anomalies continued to strengthen, La Niña conditions were developing across the equatorial Pacific this month.  The temperature outlook indicates a higher probability of above normal temperatures for most of Colorado, the southwest corner of Wyoming, and far northeastern North Dakota.  Equal chances of above, near, or below normal temperatures are predicted elsewhere.  The precipitation outlook indicates a higher probability of above normal precipitation for South Dakota, all but the northwest corner of North Dakota, Nebraska, the eastern half of Colorado, the western half of Kansas, and eastern Wyoming.  Southwestern Wyoming and western Colorado both have a higher probability of below normal precipitation.  Equal chances of above, near, or below normal precipitation are predicted elsewhere in the Region.  The seasonal outlooks combine the effects of long-term trends, soil moisture, and when applicable, the El Niño Southern Oscillation cycle (ENSO).  More information about these forecasts can be found here.

Drought Watch

While some areas of the High Plains Region received record setting precipitation, other areas were still experiencing either abnormally dry or drought conditions.  Abnormally dry conditions (D0) in Colorado were unchanged in the north and trimmed down in the south, while D0 were expanded north from Oklahoma into Kansas.  Large changes occurred this month in western Wyoming as a reassessment of conditions caused the severe drought conditions (D2) to be downgraded to moderate drought conditions (D1).  The remaining D1 areas were downgraded to D0.  North Dakota, South Dakota, and Nebraska remained drought free.  According to the U.S. Seasonal Drought Outlook released July 15th, the drought conditions in western Wyoming were expected to persist through October 2010.