Heavy rain dropped by Hurricane Hanna caused flash floods in South Texas on Sunday. Radar estimates of the rainfall indicated that 10-15 inches (3 to 5 meters) of rain fell on parts of Lower Rio Grande Valley during the passage of former Hurricane Hanna. A weather station in McAllen, Texas measured 8.24 inches (209 mm) of rain. Flash Flood Warnings were in effect for West Central Cameron County, Southern Hidalgo, Southwest Jim Hogg County, and Central Zapata County. The Arroyo Colorado in Harlingen, Texas rose from 5.2 feet (1.6 meters) to 20.72 feet (6.3 meters) and it was still rising.
Rain was still falling over parts of the Lower Rio Grande Valley even though the center of former Hurricane Hanna had moved over northeastern Mexico. At 5:00 p.m. EDT on Sunday the center of Tropical Depression Hanna was located at latitude 25.6°N and longitude 100.6°W which put it about 35 miles (55 km) west-southwest of Monterrey, Mexico. Hanna was moving toward the west-southwest at 9 m.p.h. (15 km/h). The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h). The minimum surface pressure was 1002 mb.
Tropical Depression Five intensified into Tropical Storm Dolly during the overnight hours. An Air Force Reserve Hurricane Hunter reconnaissance aircraft found that the maximum sustained wind speeds around Tropical Depression Five had increased to tropical storm force and the National Hurricane Center upgraded the system to Tropical Storm Dolly. The plane also found that a new center of circulation had developed farther to the north of the previous center and the government of Mexico extended the Tropical Storm Warning northward to Barra El Mezquital.
At 8:00 a.m. EDT on Tuesday the center of Tropical Storm Dolly was located at latitude 23.0°N and longitude 95.7°W which put it about 145 miles east-southeast of La Pesca, Mexico and about 220 miles south-southeast of Brownsville, Texas. Dolly was moving toward the west-northwest at 13 m.p.h. The maximum sustained wind speed was 50 m.p.h. and the minimum surface pressure was 1005 mb. A Tropical Storm Warning is in effect from Tuxpan to Barra El Mezquital, Mexico.
Dolly is expected to continue to move toward the west-northwest and it could make landfall in northern Mexico later today. The Sea Surface Temperatures in the western Gulf of Mexico are very warm and some further intensification is likely. Locally heavy rains are possible after Dolly makes landfall.
A low pressure system over the southern Bay of Campeche has been classified as Tropical Depression Five (TD5). At 5:00 p.m. EDT on Sunday the center of TD5 was located at latitude 20.1°N and longitude 93.6°W which put it about 255 miles east-southeast of Tuxpan, Mexico and about 465 miles south-southeast of Brownsville, Texas. TD5 was moving toward the west-northwest at 13 m.p.h. The maximum sustained wind speed was 30 m.p.h. and the minimum surface pressure was 1009 mb. A Tropical Storm Warning has been issued for the portion of the coast from Tuxpan to La Pesca, Mexico.
TD5 is expected to move toward the west-northwest and intensify into tropical storm Dolly before it makes landfall. The circulation of TD5 is interacting with a small upper level low north of the system, which is creating some northwesterly shear over it. The shear is causing most of the thunderstorms and stronger winds to occur southeast of the center. The shear will also limit intensification over the short term. Heavy rain may be possible to the north of the center when the system makes landfall.
An area of low pressure associated with the northern edge of a tropical wave has moved out over the southern Bay of Campeche. An Air Force Reserve Hurricane Hunter reconnaissance aircraft is flying through the the system and the plane has found southwesterly winds to 35 m.p.h. on the south side of the disturbance. The strongest winds are currently on the southern side of the circulation. If the plane is able to identify a well defined center of circulation at the surface, then the system could be classified as a tropical depression or tropical storm at 5:00 p.m. EDT.
The low pressure system is moving toward the west-northwest at 13 m.p.h. Many models are predicting that the motion will continue and the system will make landfall in Mexico in the 36-48 hours. Some intensification is predicted before the system makes landfall. However, confidence in the model forecasts will increase once a center of circulation is identified and is used to initialize the models.