Widespread rain was the weather story today in the Rio Grande Valley. A low level disturbance from the northeast combined with daytime heating and the sea breeze to produce showers and thunderstorms in the Valley. There is still a chance at an afternoon shower or storm tomorrow. Unfortunately, drier air will be filtering in by Saturday. This will make for a very hot weekend. Afternoon high temperatures could reach record breaking values due to subsidence air from Hurricane Irene which will bring a dry, northerly flow aloft. The good news is, the Valley did see some good rain today. The bad news is, it wasn’t nearly enough to lift the drought.
Like I said above, it is very possible that records can be broken and even shattered across the Valley this weekend. Surface dewpoint temperatures in the afternoon will be in the 50s in most areas of the upper Valley. Low dewpoint temperatures means drier air and drier air means more heat absorbed by the air.
Here are the forecast temperatures for Saturday and Sunday across the Valley according to the NWS in Brownsville: