HARLINGEN, Texas (ValleyCentral) — September is historically the wettest month in the Rio Grande Valley, but it has been nothing of the sort over the last 30 days. Outside a few sea-breeze showers around the Valley this past month, much of the region is in need of rain.
Harlingen has only seen 8% of normal rainfall over the last 30 days, while McAllen has only seen 22% of normal rainfall. In addition to the lack of normal rainfall, the newly updated United States Drought Monitor has D-0 Abnormally Dry conditions in Jim Hogg, Zapata, and parts of northwestern Starr County.
Just in the nick of time, rain chances are on the rise for the weekend and will linger into next week. The other good news is this is looking more likely a long soaking type of rain event instead of an all at once flood event. While isolated flooding issues can not be outruled, this will be mainly beneficial rain.
The system that will bring the rain is currently in the Caribbean. The National Hurricane Center gives this tropical wave a 30% chance of tropical development over the next 5 days. If this were to develop it likely won’t be until it gets in the Bay of Campeche region of the southern Gulf of Mexico. The European model gives this wave a moderate chance of becoming a tropical depression by this weekend.
This tropical wave will meet an area of upper-level low pressure, with the combination of the two reaching South Texas on Saturday into Sunday. This moisture will likely linger into early next week. The exact track and strength still has some question marks, but will likely bring several days of moisture to the region.
Current rainfall projections put the heavier rainfall accumulations in the Lower Valley, where we will likely see 2 to 4 inches of rainfall over a period of several days. Meanwhile, the Upper Valley will be closer to 0.5 to 1 inch of rainfall. That said, isolated spots could see heavier amounts depending on the rainfall rates. Additionally, clouds and moisture will keep temperatures in check with highs in the upper 80s and low 90s across the Valley.