For most of September, it seemed like the very hot summer was never going to end. Triple digit daytime heat, rain-free weather and frequent breezes continued to allow drought conditions to deteriorate across the Rio Grande Valley. A persistent upper level ridge of high pressure continued to spread from the SW U.S. into the eastern half of the nation through the first half of the month.
Occasional showers developed along the sea breeze and showers and thunderstorms developed along a weak cold front that pushed through the early in the month. By the middle of the month, a piece of a diving trough finally displaced the upper ridge, also referred to as La Canicula (from the occurrence of mid July through late August hot weather with the location of Sirius in the night sky).  The ridge began to retrograde west towards Baja California. Despite the necessary ingredients being in place (lifting of warm and humid low and mid level air, a favorable upper level jet pattern, and an area of surface low  pressure) widespread rain did not occur.
Only splotchy heavy rainfall fell, with the heaviest rain falling on Friday September 14th across the Valley. Another weak frontal boundary and more seabreeze activity on the 18th and 19th provided spotty, but much needed, rainfall across the Lower and Mid Valley.  Tropical cyclones were non existent for the Texas coast through September, held off by very dry air associated with the ridge and its frequent extension into the southern and central Plains states. The only help - though slight - from the tropics occurred from the Eastern Pacific.  Remnant moisture from Hurricane Miriam and offspring Tropical Storm Norman (near Baja) provided pockets of heavy rainfall on the 28th and 29th, which would briefly improve conditions across the Rio Grande Plains to begin October.

Drought in KENEDY, TEXAS
From 01-SEP-12 00:00:00 to 30-SEP-12 23:59:00 (CST-6)
Property damage: 0.00K
Reported by: Drought Monitor

Isolated showers and thunderstorms allowed Sarita to receive 2.33 inches of rain through the 19th of the month. Despite spotty rainfall across the county, Extreme D3 drought conditions dominated the month. A stripe of Exceptional (D4) Drought would begin the month across the northern third of Kenedy County.  By the third week of the month, isolated rainfall allowed for a slight improvement in drought conditions across the northern third of the county (down to D3), while lesser rains along the Brooks County line nudged D4 conditions to a sliver along the western county border.

Drought in BROOKS, TEXAS
From 01-SEP-12 00:00:00 to 10-SEP-12 23:59:00 (CST-6)
Property damage: 0.00K
Reported by: Drought Monitor

Isolated showers and thunderstorms dropped over just over an inche of rain across northern Brooks County from the 31st of August through the 10th of September. However, continued hot days with low to moderate humidity did little to maintain good soil moisture. A stripe of Exceptional (D4) Drought across the northern quarter of the county, with Extreme (D3) Drought elsewhere, prevailed through the 10th.

Drought in STARR, TEXAS
From 04-SEP-12 00:00:00 to 30-SEP-12 23:59:00 (CST-6)
Property damage: 0.00K
Reported by: Drought Monitor

Despite isolated showers and thunderstorms dropping around 0.75 inches of rain in pockets of the county, during early September, more intense drought conditions began to spread west across the eastern half of the county. The far eastern quarter of the county deteriorated from Severe D2 drought conditions to Extreme D3 drought conditions, while the center eastern quarter of the county entered D2 drought conditions from D1 drought conditions. The western half of the county remained in D1 and D0 drought conditions.

Drought in JIM HOGG, TEXAS
From 01-SEP-12 00:00:00 to 30-SEP-12 23:59:00 (CST-6)
Property damage: 0.00K
Reported by: Drought Monitor

Isolated showers and thunderstorms dropped 1.76 inches of rain at Hebbronville through the 19th of the month. Despite this rainfall, Exceptional, D4, drought conditions continued to spread south across the county, encompassing the far eastern third of the county. By the third quarter of the month, Extreme, D3, drought conditions spread over the remainder of the county.

Drought in HIDALGO, TEXAS
From 01-SEP-12 00:00:00 to 24-SEP-12 23:59:00 (CST-6)
Property damage: 0.00K
Reported by: Drought Monitor

Despite isolated showers across the county, dropping .5 to over 3 inches through the 19th of the month, there was no improvement in drought conditions in Hidalgo County. The county remained completely entrenched in Extreme, D3, drought conditions.  By the third quarter of the month, drought conditions deteriorated further across the NE corner of the county, where Extreme, D3, drought conditions slipped into Exceptional, D4, drought conditions.

Drought in COASTAL CAMERON, TEXAS
From 04-SEP-12 00:00:00 to 30-SEP-12 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Drought Monitor

Despite isolated showers during the first three quarters of the month, coastal Cameron County remained firmly entrenched in Extreme, D3, drought conditions from September 4th through 30th.

Drought in COASTAL WILLACY, TEXAS
From 04-SEP-12 00:00:00 to 30-SEP-12 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Drought Monitor

Isolated pockets of rain fell across coastal Willacy County during the first three weeks of the month. Some areas received greater than 1.75 inches of rain, but the area remained firmly entrenched in Extreme, D3, drought conditions, from the 4th through the 30th.

Drought in CAMERON, TEXAS
From 04-SEP-12 00:00:00 to 30-SEP-12 23:59:00 (CST-6)
Property damage: 0.00K
Reported by: Drought Monitor

Despite spotty rainfall of half an inch to over an inch across the county, drought conditions intensified and Extreme D3 drought conditions spread further east and south across the county, firmly entrenching the entire county into Extreme D3 drought conditions which continued through the end of the month.  Despite some welcome rainfall along the river near Brownsville during the final three days of the month (2.75 inches total), the monthly total (3.76 inches) ended more than 2 inches below long term averages (5.92 inches).

Drought in WILLACY, TEXAS
From 04-SEP-12 00:00:00 to 30-SEP-12 23:59:00 (CST-6)
Property damage: 0.00K
Reported by: Drought Monitor

Despite spotty rainfall of less than half an inch across the county, drought conditions intensified and Extreme, D3, drought conditions engulfed the entire county from the 4th through the 30th.