After about 3 days in the Gulf of Mexico, Invest 93 is finally beginning to make landfall in northern Mexico. Most of the shower and thunderstorm activity connected with this tropical low pressure will stay in northern Mexico, but the Rio Grande Valley and south Texas could still see some showers and thunderstorms from the sea-breeze. This morning’s Brownsville sounding, shown below, shows tropical easterly winds from the surface to about 500 mb, with a near saturated boundary layer. It also recorded precipitable water (PW) values at 1.61 inches. This sounding is favorable for shower and thunderstorm development in the afternoon hours. This doesn’t mean it will rain everywhere, unfortunately. If you get rained on, consider it lucky for you.
The Rio Grande Valley is in desperate need of rain. As you can see in the figures below, the National Weather Service in Brownsville, TX keeps rainfall records across the Valley. The top image shows the total amount of rainfall for the month of May, 2011. The bottom image shows total rainfall amount from the period of October 1, 2010 through May 31, 2011. Most sites across the Valley have broken dry records in this time frame.