National Weather Service United States Department of Commerce

 

Drought Dented in Lower RGV
Days of Locally Heavy Rain Greens Things Up
Preliminary Rainfall, September 8 through 11
Location County Rainfall
Brownsville 2.2 W
Cameron
8.16
Falcon Dam
Zapata/Starr
7.70
Rancho Viejo 3.0 SE
Cameron
7.27
Brownsville 4.9 NW
Cameron
7.08
Brownsville/SPI International Arpt.
Cameron
6.17
Brownsville 6.4 SE
Cameron
6.09
Brownsville 4.1 E
Cameron
5.62
Rancho Viejo
Cameron
5.52
Brownsville 4.5 NNW
Cameron
5.17
Brownsville 3.5 N
Cameron
5.12
Sarita
Kenedy
5.02
Brownsville 4.4 NE
Cameron
4.96
Brownsville 4.6 NNW
Cameron
4.76
Bayview/Cameron County Airport
Cameron
4.72
Los Fresnos
Cameron
4.68
Santa Ana/Lower RGV NWR
Hidalgo
4.55
Brownsville 4.1 ENE
Cameron
3.84
Armstrong
Kenedy
2.83
McAllen/Water Plant Co-op
Hidalgo
2.81
Rio Grande City
Starr
2.65
Falfurrias
Brooks
2.63
Brownsville 4.1 NNE
Cameron
2.56
Falcon Lake
Zapata
2.49
Weslaco
Hidalgo
2.39
Harlingen/Valley Int'l Airport
Cameron
2.36
San Benito 5 SSE
Cameron
2.14
Edinburg
Hidalgo
1.78
Lyford
Willacy
1.78
Port Mansfield
Willacy
1.77
Laguna Atascosa NWR
Cameron
1.74
McAllen/Miller Int'l Airport
Hidalgo
1.72
La Joya 11.1 N
Hidalgo
1.37
Linn San Manuel/Lower RGV NWR
Hidalgo/Willacy
1.33
Harlingen 4.7 WSW
Cameron
1.28
Raymondville
Willacy
1.22
La Joya
Hidalgo
1.14
Harlingen 4.3 WSW
Cameron
1.08
Mission 1.5 ENE
Hidalgo
0.99
Hebbronville
Jim Hogg
0.86
Rio Hondo 9.4 NE
Cameron
0.48

Quick Review
Persistent weak upper level disturbances combined with abundant and deep tropical moisture to produce scattered to numerous torrential showers and thunderstorms for the first work week following Labor Day 2009, which fell on September 7th. Heavy rains developed in banded showers which formed near and along the Lower Texas and Tamaulipas (Mexico) coast late each night, moving onshore into Cameron and Willacy County from early morning through mid morning, and sometimes advancing or developing into eastern Hidalgo, Brooks, and Kenedy County before noon. Pulse–type storms developed in a more scattered, "popcorn" pattern, across Starr, Jim Hogg and Zapata County. A very small but intense thunderstorm complex unleashed more than 7 inches of rain near Falcon Dam along the Starr/Zapata County line during the evening of September 9th; nearly 8 inches of rain fell at Falcon Dam, doubling the average monthly total in just a few hours!

Impacts
For most, the parched ground readily soaked up much of the rainfall. By Thursday, however, locations which had received more than 6 inches were seeing standing water and nuisance, non life or structural flooding. These locations included extreme southern Cameron and extreme southeast Hidalgo County, as well as the Roma through Falcon Heights and Lopeño area along the Starr/Zapata County line. Poor drainage flooding was common along and near Highway 281 through Highway 77 in Brownsville and points west by the evening of September 10th, as measured and estimated rainfall of 3 to 5 inches fell near the River Bend and Quail Hollow communities.

An additional 1 to 2 inches fell across Cameron, extreme eastern Hidalgo, and Kenedy County on September 11th. By late afternoon, the trough and associated moisture began pulling away, and dry air returned for the weekend of September 12th and 13th.

A map of measured and estimated rainfall for September 8th through 11th can be found here.