Firsthand Weather is keeping a very close eye on the convection located over the southeastern Gulf of Mexico and northwestern Caribbean (see Fig. 1). This area of convection will persist over the next 48 hours and should begin to organize by 48-72 hours into Tropical Depression/Storm Joyce. Right now, the upper-level winds are not conducive for organization but these winds will become more favorable by late week. The majority of the European ensemble members are showing development with a northwest movement into southern Texas by Friday (see Fig. 2) and the GFS and Canadian show a decent area of pressure falls (hinting at a Tropical Depression/Storm) in the same vicinity. This is why the National Hurricane Center (NHC) has given this area a 50% chance of development over the next two days and a 70% chance of development by day five (see Fig. 2).
Fig. 1: Convection that may develop into Joyce later this week
Fig. 2: European ensembles
Fig. 3: Area being monitored by the NHC
By late week, what could be Tropical Storm Joyce should be in the western Gulf. This will lead to copious amounts of moisture moving into south and coastal parts of Texas. Widespread 4-8″ of rainfall are possible with the possibility of amounts exceeding 10″ in areas (see Fig. 4). This part of Texas has received above average precipitation as of late, thus, the grounds are saturated; leading to an enhanced flash flood threat for the region from Thursday through the upcoming weekend.
Fig. 4: 7-day rainfall forecast
While a general WNW to NW motion is what is depicted by numerical guidance, much uncertainty does exist with the track of this system. Generally, the consensus of guidance has a landfall between Corpus Christi and South Padre Island. This could deviate further south or further north depending on the strength of the system. A stronger Tropical Storm/Hurricane would likely force a more WNW motion due to the 500mb ridge possibly intensifying to the north whereas a weaker Tropical Depression/Tropical Storm would likely track more to the NW.
Regardless of development into Tropical Storm Joyce, this system will lead to an influx of moisture into parts of southern Texas, which will increase the flood threat. Other hazards associated with this area of disturbed weather for Texas are: rough seas, rip currents and gusty winds. Keep checking back for updates because the waters are warm in this area so if organization occurs faster than expected, it is possible this system could ramp up quickly.