An upper level disturbance forming across South Texas could bring heavy rainfall and minor flooding to the Rio Grande Valley this week, the National Weather Service in Brownsville reported Sunday.
Rick Hallan, a NWS meteorologist, reports the heaviest rainfall will happen across the northern ranchlands and western brush country Tuesday into Thursday night.
Isolated flash flooding is possible in the Valley.
There’s a 20% chance of thunderstorms Sunday afternoon and a 30% chance of thunderstorms on Monday. That increases to a 50% chance of heavy rain on Tuesday.
The rain chances continue to rise with a 70% chance of heavy rain Tuesday night, a 60% chance of heavy rain on Wednesday, and a 70% chance of heavy rain on Wednesday night and Thursday.
The rain chances begin to decrease on Friday with a 50% chance of rain.
The NWS reports that from Brownsville to Rio Grande City 2 to 3 inches of rain could occur during the week.
A flash flood watch may need to be issued later this week, the NWS said.
Because of the rain, the temperatures during the week will be in the upper 80s to low 90s.
Hall writes that the potential threats and impacts from the upper level disturbance are the following:
>> Rainfall of 3-6″, mainly across the ranchlands, with locally higher amounts through Saturday
>> Flash flooding and minor flooding, especially across low-lying and poor-draining areas
>> Occasional to frequent cloud to ground lightning during thunderstorms
