August 2009 Climatic Summary

August was a cool month with temperatures averaging 2 to 4 degrees below normal. All locations reported below normal temperatures in August. Gillette 4SE in northeast Wyoming was the warm spot averaging 0.6 degrees below normal. The cold spot was at Colony in northeast Wyoming where temperatures averaged 7.0 degrees below normal.
Precipitation in August averaged 30 to 50 percent above normal. The wettest areas were across the northeast Wyoming plains…the northern Black Hills…northern foothills and over the Bear Lodge Mountains where precipitation averaged 175 to 250 percent of normal. The driest areas were across the plains of western South Dakota south and east of the Black Hills where precipitation was 60 to 80 percent of normal. The wet spot was at Colony in northeast Wyoming, where precipitation was 320 percent of normal. Edgemont was the dry spots with only 47 percent of normal precipitation. The precipitation surplus for the month averaged 0.60 inches.
No snowfall was reported during the month of August.
 

August storm summary...

On August 3…An upper level disturbance brought severe thunderstorms to southern South Dakota and the southern portions of Campbell and Weston counties in northeast Wyoming. There were numerous reports of wind gusts of 60 to 70 mph, with the strongest gust of 83 mph occurring 8 miles southwest of Rochelle in Campbell County.
There was only one hail report, when golf ball size hail was reported 3 miles south of Hamill in Tripp County.
 
On August 4…An upper level disturbance brought severe thunderstorms to northeast Wyoming and far western South Dakota. There were numerous reports of wind gusts of 60 to 65 mph with the strongest gust of 83 mph occurring at Echeta in Campbell County.
 
On August 5…An isolated severe thunderstorm in northeast Wyoming brought golf ball size hail and 60 mph winds to Pine Haven in Crook County.
 
On August 6…An isolated severe thunderstorm in the morning dropped Ping Pong ball size hail in Colony in Crook County and quarter size hail 5 miles north of Newell in Butte County. In the afternoon an isolated severe thunderstorm produced 60 mph winds and quarter size hail 7 miles southeast of Clareton in Weston County.
 
On August 7…A severe thunderstorm moved from Deadwood to Sturgis during the Harley Davidson Rally. This storm produce golf ball size hail 2 miles northeast of Deadwood, and baseball size hail and 70 mph winds in Sturgis. Hundreds of vehicles and motorcycles were damaged. This storm continued east producing large hail and damaging winds across Meade and Haakon counties. As the storm moved through Haakon County it produced 3 inch diameter hail 17 miles northwest of Philip.
 
On August 8…During the morning hours a severe thunderstorm produced quarter size hail and 60 mph winds near Hulett and Moorcroft in Crook County. Another severe thunderstorm produced quarter size hail 5 miles southeast of Clearfied in Tripp County. During the late afternoon a severe thunderstorm produced quarter size hail and 60 mph winds near Belle Fourche and Nisland in Butte County.
 
On August 9…An isolated severe thunderstorm produced 60 mph winds near Sharps Corner and 11 miles north of Porcupine in Shannon County.
 
On August 12…An isolated severe thunderstorm dropped large hail in Mellette and Jackson counties and produced 60 mph winds 6 miles southeast of Ideal in Tripp County. The largest hail reported was the size of golf balls 4 miles south of White River in Mellette County.
 
On August 13…An isolated severe thunderstorm blew down large tree branches 4 miles southeast of Interior in Jackson County.
 
On August 15…An isolated severe thunderstorm produced 60 to 70 mph winds across Shannon and Jackson counties. Wind gusts of 70 mph were reported 1 mile south of Oglala in Shannon County and 11 miles northeast of Wanblee in Jackson County.
 
On August 23…An isolated severe thunderstorm produced 70 mph winds at Buffalo in Harding County.

 LOCAL EXTREMES

Temperature Data

Rapid City

 

Lead

 

Gillette

 

 

Temperature

Date

Temperature

Date

Temperature 

Date

Maximum Temperature

97 degrees

13th

88 degrees

13th, 23rd

96 degees

22nd, 23rd

Minimum Temperature

42 degrees

1st

40 degrees

21st

39 degrees

21st

Precipitation Data

Rapid City

 

Lead

 

Gillette

 

Monthly Data

Amount

Data

Amount

Date

Amount

Date

Precipitation

1.48 inches

 

3.20 inches

 

2.10 inches

 

Snowfall

0.0 inches

 

0.0 inches

 

0.0 inches

 

 

 

 

 

 

 

 

Daily Data

 

 

 

 

 

 

Maximum Precipitation

0.52 inches

9th

1.05 inches

9th

0.61 inches

8th

Maximum Snowfall

0.0 inches

 

0.0 inches

 

0.0 inches

 

 
 REGIONAL EXTREMES

Temperature Data

 

Western South Dakota

 

 

Northeastern Wyoming

 

 

Temperature

Site

Date

Temperature

Site

Date

Maximum Temperature

102 degrees

Cottonwood 2E Edgemont

12th
13th

98 degrees

Dillinger

22nd

Minimum Temperature

33 degrees

Ladner 9SW

21st, 22nd

33 degrees

Upton 14 ENE

16th

Precipitation Data

 

Western South Dakota

 

 

Northeastern Wyoming

 

Monthly Data

Amount

Site

Date

Amount

Site

Date

Maximum Precipitation

5.09 inches

Winner

 

4.02 inches

Sundance

 

Minimum Precipitation

0.73 inches

Edgemont

 

1.83 inches

Wright 12W

 

Maximum Snowfall

0.0 inches

 

 

0.0 inches

 

 

Minimum Snowfall

0.0 inches

 

 

0.0 inches

 

 

 

 

 

 

 

 

 

Daily Data

 

 

 

 

 

 

Maximum Precipitation

2.39 inches

Winner

5th

1.71 inches

Sundance

8th

Maximum Snowfall

0.0 inches

 

 

0.0 inches

 

 


 MONTHLY RECORDS

LOCATION

DATE

NEW RECORD

OLD RECORD

DATE

Colony, Wy.

August

64.6 degree average temperature

65.5 degree average temperature

1927

 

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