National Weather Service Huntsville, AL -- August 2013 Climate Summary

August 2013 Climate Summary for Huntsville and Muscle Shoals...

Temperatures...

After a relatively cool July, August 2013 likewise ended on the cool side for northern Alabama and surrounding areas. The month was perhaps most memorable, meteorologically speaking, for its relative lack of very hot conditions. At Huntsville, the monthly average temperature finished 2.8 degrees below normal. Temperatures were a little warmer at Muscle Shoals, but still finished 1.7 degrees below normal there. The thermometer at Huntsville didn't officially climb above 90 degrees until the 22nd, and only reached the 90s on five more days after that. However, one only has to go back to 2004 to find an August with less 90 degree days. Ninety degree temperatures were certainly more common at Muscle Shoals, occurring on 15 days during the month, but this is still less than the long-term average. Cloudy conditions and a cooler airmass entered the region during the middle of the month. Daytime high temperatures at Huntsville did not rise above 80 degrees for a period of approximately 4 days and 21 hours...from the afternoon of the 14th through the early afternoon of the 19th. This was the longest such stretch during the month of August since a similar streak occurred from August 17th -22nd, 1981. The high temperature of 71 degrees on the 17th was just one degree warmer than the normal low for the date. Record low maximum temperatures were set at Huntsville on the 17th and at both Huntsville and Muscle Shoals on the 18th.

Daily Temperature Graphs for the month of August for each location (click on the images for a larger version).

Huntsville - Aug 2013 Temperature Graph	Muscle Shoals - Aug 2013 Temperature Graph

Temperature Statistics for the Month of August at Huntsville and Muscle Shoals. All temperatures are in degrees Fahrenheit.

August Statistic	Huntsville	Muscle Shoals
Average Monthly Temperature	77.3	78.1
Normal Temperature*	80.1	79.8
Deviation From Normal	2.8 Below Normal	1.7 Below Normal
Monthly Ranking**	24th Coolest	39th Coolest
Warmest August	85.7 (2007)	85.5 (2007)
Coolest August	73.8 (1967)	74.1 (1967)
Max Temperature	95 (Aug 31st)	96 (Aug 31st)
Min Temperature	58 (Aug 15th)	61 (Aug 15th)
All-Time Max Temperature	108 (Aug 7-8, 1930)	108 (Aug 8, 1930)
All-Time Min Temperature	50 (Aug 26, 1917)	47 (Aug 26, 1917)
Record Highs	None	None
Record Lows	74 on Aug 16 (Low Maximum) 71 on Aug 17 (Low Maximum)	74 on Aug 17 (Low Maximum)

Precipitation...

August precipitation was generally scattered in nature, as is often the pattern this time of year, resulting in a wide range of precipitation totals and anomalies, from around three inches below normal to around four inches above normal. At Huntsville International Airport, rainfall was relatively low, totaling just 1.81 inches. However, some locations within Huntsville city proper received much higher totals...eclipsing eight and nine inches in some instances (CoCoRaHS reports). This demonstrates the scattered nature of showers and thunderstorm activity typical during the month of August. At Muscle Shoals, 5.70 inches was measured during the month, which was 2.55 inches above normal. A new daily record was set there on the 9th, when 2.04 inches of precipitation was recorded. Meanwhile, the official precipitation at Huntsville (airport) did not even reach one half inch on any day during the month. The greatest daily total at Huntsville was only 0.47 inches, which occurred on the 22nd.

Precipitation Estimates and Departures from Normal for August for the Huntsville Forecast Area (amounts are in units of inches).

Precipitation Estimates	Precipitation Departures from Normal

August Precipitation Statistics for Huntsville and Muscle Shoals (amounts are in units of inches).

August Statistic	Huntsville	Muscle Shoals
Monthly Precipitation	1.81	5.70
Normal Precipitation	3.61	3.15
Departure from Normal	1.80 Below Normal	2.55 Above Normal
Monthly Ranking	25th Driest	20th Wettest
Wettest August	12.61 (1901)	10.60 (1916)
Driest August	0.08 (1918)	0.43 (1944)
Wettest Calendar Day (2013)	0.47 (Aug 22nd)	2.04 (Aug 9th)
Record Wettest Day	4.29 (Aug 10, 1986)	4.29 (Aug 1, 1938)
Precipitation Records	None	2.04 (Aug 9th)

The Monthly Outlook for September from the Climate Prediction Center...

The one month temperature outlook indicates equal chances for above, near or below normal temperatures for the Tennessee Valley climatic zones. The 3-tiered probabilities are as follows...

Above Normal....33%
Near Normal......34%
Below Normal....33%

The one month precipitation outlook indicates slightly higher chances for above normal precipitation for the central Tennessee Valley climatic zones. The 3-tiered probabilities are as follows...

Above Normal....35%
Near Normal......33%
Below Normal....32%

What is normal for September? ...Huntsville daily normals and records / Muscle Shoals daily normals and records

* Normal temperatures and precipitation are based on the 1981-2010 climatological period. All temperature data are expressed in degrees Fahrenheit.
** Temperature data for Huntsville go back to 1907, while precipitation data are available since 1894. Any months that contain missing daily temperature or precipitation data are not counted in the rankings.

*** Temperature and precipitation data for Muscle Shoals go back to 1893, however sporadic outages of data occur especially in the 1910s and again from September 1995 through May 1997. Any months that contain missing daily temperature or precipitation data are not counted in the rankings.

Note...all data above are preliminary and have not undergone final quality control by the National Climatic Data Center (NCDC). Therefore, these data are subject to revision. Final and certified data can be accessed at the NCDC at the following location... http://www.ncdc.noaa.gov

One month and seasonal temperature and precipitation outlooks may be obtained from the Climate Prediction Center at the following location...http://www.cpc.ncep.noaa.gov

KDW

National Weather Service Weather Forecast Office