August 2013 Monthly Climate Summary

...AUGUST 2013 MONTHLY CLIMATE SUMMARY...

Despite a mid-month preview of temperatures better related with fall as opposed to late summer, August 2013 in the Mid-South ended with monthly average temperatures that were just below normal. This is due to the fact that the below normal temperatures, with highs as low as 80 in Memphis, only lasted for about a week, and warmer weather returned late in the month. Jackson was the site with the greatest average temperature departure from normal this month, at nearly two degrees below normal. Jonesboro was closest to normal at only a tenth of a degree below normal, while Tupelo and Memphis were both 0.9 degrees below normal for the month of August. At this point in 2013, Jonesboro is the closest to normal at only 0.4 degrees below normal, Tupelo is 0.9 degrees below normal, Memphis is 1.1 degrees below normal, and Jackson is 1.4 degrees below normal.

Both Memphis and Jackson received less than normal amounts of precipitation in August, with 0.71 inches below normal and 1.27 inches below normal, respectively. Jonesboro was the wettest site with 3.72 inches of rainfall during August, 1.18 inches above normal, while Tupelo was 0.42 inches above normal for the month with 3.87 inches. All sites are still above normal for 2013 so far, although Tupelo is now within a degree of normal, at only 0.81 inches above normal for the year. For 2013, Memphis has the highest departure above normal at nearly 11 inches, having received nearly 46 inches of rain. Below are the data for August 2013 across the Mid-South.

TEMPERATURE DATA:

                               Memphis   Jackson   Jonesboro  Tupelo

Average Temperature (AUG)    :   81.1     76.8      79.7      79.9

Normal Avg. Temp (AUG)       :   82.0     78.6      79.8      80.8

Departure from Normal (AUG)  :   -0.9     -1.8      -0.1      -0.9

Average Temperature (YEAR)   :   63.9     60.4      61.7      63.4

Normal Avg. Temp (YEAR)      :   65.0     61.8      62.1      64.3

Departure from Normal (YEAR) :   -1.1     -1.4      -0.4      -0.9

PRECIPITATION DATA:

                                Memphis   Jackson   Jonesboro  Tupelo

Total Precipitation (AUG)    :    2.17      1.73      3.72     3.87

Normal Precipitation (AUG)   :    2.88      3.00      2.54     3.45

Departure from Normal (AUG)  :   -0.71     -1.27      1.18     0.42

Total Precipitation (YEAR)   :   45.95     45.09     37.45    37.28

Normal Precipitation (YEAR)  :   35.38     35.87     31.11    36.47

Departure from Normal (YEAR) :   10.57      9.22      6.34     0.81

Summer 2013 Review:

Now that the warmest months of the year are in the history books, a look back at June, July, and August will show that the Mid-South has had a near normal summer. In fact, when taking the average of the average temperatures for June, July, and August collectively, Jackson is the only site with more than a degree departure from normal, at 1.6 degrees below normal. Jonesboro is the only site that had an above normal average temperature this summer, at only 0.1 degrees above normal. Memphis was only 1.0 degree below normal, while Tupelo was 0.7 degrees below normal. To take this a step further, it appears as though the maximum temperatures had more to do with the slightly below normal average temperatures this summer, as there is more of a departure from normal among the average maximum values than there is with the average minimum values. This means that the daily high temperatures had more of a deviation from normal than the daily low temperatures.

Memphis’ average maximum, or high, this summer was 89.2 degrees, 1.4 degrees cooler than the normal maximum of 90.6 degrees. At the same time, Memphis’ average minimum, or low, temperature this summer was 71.6 degrees, which was only 0.7 degrees cooler than the normal minimum of 72.3 degrees. Jackson’s average high this summer was 86.9 degrees, 2.4 degrees cooler than the normal high of 89.3, while its average low was 66.2 degrees, which was only 0.7 degrees cooler than the normal low of 66.9 degrees. Jonesboro had an average high of 89.9 degrees, which was actually 0.1 degrees warmer than normal, while its average low was 69.4 degrees, 0.2 degrees warmer than normal. Finally, Tupelo’s average high this summer was 89.2 degrees, which was 1.4 degrees cooler than the normal high of 90.6 degrees, while its average low was 69.5 degrees, only 0.1 degrees cooler than normal. In terms of precipitation, only Memphis and Jonesboro saw above normal amounts this summer at 0.27 inches above normal and 1.28 inches above normal, respectively. Jackson and Tupelo both had below normal precipitation amounts at 2.22 inches below normal and 3.02 inches below normal, respectively.

While summer 2013, or at least the warmest parts of it, may have seemed cooler than normal, which technically it was, it really was not that far from normal. Perhaps this is because so many remember well the scorching summer of 2012 which broke many records for high temperatures. In comparison with 2012, we were much cooler this summer. Many days last summer saw temperature values at or in excess of 100 degrees, while none of the four sites used in this summary saw 100 degrees this summer. On average, Memphis reaches 100 degrees for the first time around July 19^th and for the last time around August 10^th. Being that we have been so near normal this summer, it would appear that we are out of the optimal range of dates for reaching 100 degrees. Below are the data that represent the climate of summer 2013 around the Mid-South.

Memphis   Jackson   Jonesboro  Tupelo

Average Temperature (JJA)  :    80.5     76.5      79.6     79.4

Normal Avg. Temp (JJA)     :    81.4     78.1      79.5     80.1

Departure from Normal (JJA):    -1.0     -1.6       0.1     -0.7

Average Maximum (JJA)      :    89.2     86.9      89.9     89.2

Normal Maximum (JJA)       :    90.6     89.3      89.8     90.6

Departure from Normal (JJA):    -1.4     -2.4       0.1     -1.4

Average Minimum (JJA)      :    71.6     66.2      69.4     69.5

Normal Minimum (JJA)       :    72.3     66.9      69.2     69.6

Departure from Normal (JJA):    -0.7     -0.7       0.2     -0.1

Total Precipitation (JJA)  :  11.37    10.11     11.11     8.85

Normal Precipitation (JJA) :  11.10    12.33      9.83     11.87

Departure from Normal (JJA):    0.27    -2.22      1.28     -3.02

Climate Outlook:

We have now completed eight months of the year, and as explained by the August data, for 2013 so far around the Mid-South we have slightly below normal average temperatures and above normal precipitation amounts. This has no doubt caused many to question what the rest of the year, and specifically September, may hold for us here in the Mid-South. The current Climate Prediction Center forecast for the month of September has us at an Equal Chance of experiencing below normal, normal, or above normal temperatures. This really does not give us much of an insight into what our temperatures will be during this new month. However, we do know that the normal average temperature for Memphis during the month of September is 75.2 degrees, while it is 71.4 for Jackson, 71.9 for Jonesboro, and 74.1 for Tupelo. The normal high temperature values are between 80 and 85 degrees around the region for the month of September. Given that our average temperatures have been near normal for the past several months, these normal values may be our best predictor as to what’s in store for September, that is if the trend we have witnessed the majority of this year continues. The Climate Prediction Center also gives the Mid-South an Equal Chance of above normal, normal, or below normal precipitation values for September.

Currently the Climate Prediction Center is giving an Equal Chance for above normal, normal, or below normal temperatures this fall, or September, October, and November, while forecasting normal to above normal precipitation values this fall.

MAYE