Climate Summary for September 2013

Precipitation for September was well-above normal across most of the southern half of west-central Texas, and across parts of the northern half of the region (Figure 1).  The monthly rainfall was more than 4.5 inches across these areas.  The highest September rainfall (between 6.5 and 8.5 inches) occurred at scattered locations across the Northern Edwards Plateau, Northwest Hill Country, and southern Heartland.  The only part of west-central Texas to receive slightly below normal monthly precipitation was in Sterling, parts of Throckmorton, and extreme northwestern Crockett Counties. 

Figure 1: Percent of Normal Precipitation for September, 2013.

Temperatures averaged above normal for the month.

At Abilene Regional Airport, the average temperature for September was 78.6 degrees.  This was 3.1 degrees above the normal average temperature of 75.5 degrees. Total precipitation for Abilene in September was 3.18 inches. This was 0.94 inches above the normal of 2.24 inches.

At San Angelo Regional Airport, the average temperature for September was 77.7 degrees. This was 2.1 degrees above the normal average temperature of 75.6 degrees.  Total precipitation for San Angelo was 4.62 inches. This was 2.16 inches above the normal of 2.46 inches.  

The number of days in September with high temperatures of 100 degrees or more  include:
1 at San Angelo, 1 at Abilene, and zero at Junction. 

Two noteable rain events occurred in September. 

A significant rainfall event (with some flooding) occurred on September 19-20.  With this event, widespread and heavy rainfall affected west-central Texas, most notably across central and southern sections of the region.  

A very moist airmass was pulled north into west-central Texas, along with the remnants of a tropical system in Mexico. With this setup, showers (with a few thunderstorms) with moderate to heavy rain developed north across the Northern Edwards Plateau during the post-Midnight hours of the 19th. The showers expanded in coverage and verspread west-central Texas through the rest of the day and into the nighttime hours.  Additional moderate to heavy rain showers (and a few thunderstorms) occurred  across west-central Texas on the 20th, as a cold front moved south into the area. The showers gradually tapered off during the evening and early nighttime hours.

Figure 2 (below) shows rainfall amounts across west-central Texas, for the September 19-20 rain event.  

Figure 2: West-Central Texas Rainfall for the 7-day period ending at 7 AM, September 21.

The highest rainfall amounts (between 5 and 7 inches) occurred in scattered areas of the Northern Edwards Plateau and western Menard County.  Rainfall totals of 3-5 inches were common across the southern Concho Valley, the Northwest Hill Country, much of the Heartland and southeastern Big Country areas. Lesser rainfall amounts (between 1 and 2.5 inches) occurred across much of the Big Country and northern Concho Valley.  A new daily rainfall record (2.43 inches) was set at San Angelo on the 19th.  

While the rainfall was beneficial for west-central Texas, where moderate to severe drought conditions were occurring prior to this event, the rain intensity and duration led to some flash flooding in the Northern Edwards Plateau, Northwest Hill Country, and parts of the Concho Valley. In all, a total of 12 flash flooding reports were received for this event.

With cloud cover and rainfall, daytime temperatures were much cooler on the 19th and 20th.  On the 20th, highs were only in the upper 60s to lower 70s.  

Another rain event occurred on the 28th.  With a moist airmass in place, numerous showers and thunderstorms occurred as a cold front entered west-central Texas. Rainfall totals for this event are shown in Figure 3 (below). 

Figure 3: West-Central Texas Rainfall for the 24-hour period ending at 7 AM, September 29.

The heaviest rainfall occurred across the area northwest of a line from  Cross Plains to Christoval to south of Ozona. Much of the Big Country received 1 to 3 inches, with isolated higher amounts. Rainfall amounts of 1-3 inches also occurred at scattered locations across the Concho Valley and western Crockett County, and at a few locations in southeastern sections of west-central Texas.     

Cloud cover, rainfall, and passage of a cold front brought a change to much cooler temperatures on the 28th.  Temperatures dropped into the 60s to lower 70s.