Discussion: An area of low pressure in the west-central Gulf of Mexico is evolving (Fig. 1) and will drift west as a strengthening tropical wave early-to-mid week bringing heavy rain to the Texas Coast tonight, Monday and Tuesday and southern Texas/northeast Mexico Tuesday/Wednesday (Fig. 2-5). The evolution of this system takes place across warmer-than-normal sea surface temperatures capable of forcing tropical cyclone development (Fig. 6). However, forecast models are doubting a tropical cyclone due to the axis of upper shear across the convection zone and proximity of this event to the Texas Coast tomorrow and Tuesday. Nevertheless several in. of rain are likely on the Texas Coast tomorrow centered on the central coast with higher amount (up to 4 in.) from Corpus Christi to Brownsville Tuesday. Excessive rains continue midweek in northeast Mexico. The 7-day rainfall forecast indicates potential for nearly 10 in. of rain on the south Texas Coast (Fig. 7).
Fig. 2-5: Evolution of a heavy rainfall episode in Texas as indicated by NOAA/WPC for Sunday/Monday (top) and Tuesday/WED & THU (bottom).
Fig. 6: The Gulf of Mexico is warmer-than-normal. Threshold for North Atlantic tropical cyclone development is 82F. Current SSTA are indicated.
Fig. 7: The NOAA/WPC 7-day rainfall forecast indicates 10+ in. of rain on the Texas Coast.