Texas and Louisiana Tropical System Impacts This Week

Invest 93 discussion

The National Hurricane Center (NHC) is still keeping a close eye on the broad surface low (Invest 93) that has developed in the western Caribbean. The pressure continues to slowly drop and confidence is high that this low will become a tropical system in the Gulf of Mexico by Monday or Tuesday. The NHC is keeping a close eye on this system and has given the low an 90% chance of development into a tropical cyclone over the next five days and a 70% chance of development within 48 hours.

Invest 93 being watched as it moves into the Gulf of Mexico

Confidence increasing in Texas and Louisiana impacts

A more northwestern movement, followed by a westward movement, is beginning to emerge within much of the numerical guidance. This is similar to what the European model and 12km NAM have been showing. The GFS and Canadian are beginning to trend westward towards this solution. While the track of this low is very complicated, it does appear this low will drift northwestward due to an upper-level trough, then begin a westward movement towards the Texas coast as a mid-level ridge (across the southwest) and the Bermuda high build in and create a barrier across the northern Gulf of Mexico, which is why the numerical guidance is trending in this direction.

Tropical system off of the Louisiana coast Tuesday afternoon (12km NAM; simulated radar)

Tropical system off of the Louisiana coast Tuesday afternoon (12km NAM; near-surface wind map)

Tropical system off of the Texas coast Wednesday morning (12km NAM; simulated radar)

Tropical system off of the Texas coast Wednesday morning (12km NAM; near-surface wind map)

Potential rainfall map through next week (NCEP)
http://firsthandweather.com/?p=2800&preview=true

This solution would cause impacts for parts of Texas and Louisiana from Tuesday through Thursday. Very heavy rainfall is possible near the coast of Texas and Louisiana (and showers are storms are possible much further inland across these states), and coastal flooding is possible due to the onshore flow from this low. The cyclonic flow around the low would allow for sea water to ‘pileup’ causing flooding for areas just above sea-level. Secondary threats are wind (depending on the strength of the system) and isolated tornadoes. The metros (and surrounding suburbs) of New Orleans and Houston could see large impacts from this system depending on the exact track.

There is high confidence in the development of this low into a tropical system, but the confidence level is much lower in regards to the movement. All residents along the Gulf Coast (from Texas to Florida) need to keep a close eye on this system. Regardless of the movement, this system will rotate in rich moisture which could cause heavy rainfall for areas further east as well (the coast of Mississippi, Alabama, southern Georgia, and Florida). Keep checking back for updates!