A tropical disturbance that moved into northern Mexico over the weekend – partly the leftover spin of once-Tropical-Storm Cristina that crossed Central America from the eastern Pacific – will hitch a ride along an unusually strong and slow-moving cold front this week through the Deep South, bringing the threat of prolonged heavy rainfall and flash flooding, starting first along the Texas Gulf Coast and South Texas today and tomorrow, stretching into the Lower Mississippi Valley and central Gulf Coast by late week.
As of Monday morning, flood watches already blanketed most of eastern Texas, Louisiana, and west-central Mississippi as moisture levels soar to record territory.
The abundant tropical air sweeping into the Texas Gulf Coast today will mean downpours that develop will be especially prolific, with incredible rainfall rates as high as 3 to 5 inches per hour posing flooding problems, even for drier soils.
Organized tropical development low but heavy rains regardless
The tropical disturbance itself, which we’ve been tracking for over a week in this newsletter, was inland over northern Mexico Monday morning. Though the advancing front to its north will drag it back eastward and perhaps briefly off the Texas Gulf Coast by Wednesday, the window for development over water – if at all – will be brief.
By early Thursday, the system will be caught in the high-altitude winds of the stalled front over eastern Texas and accelerating toward northern Louisiana, Mississippi, Alabama, and Georgia for Friday. While forecast models suggest the low-pressure area could strengthen over land later this week, it won’t be through tropical processes but rather from strong jet-stream winds.
Nevertheless, the impacts will feel tropical-like in terms of the influx of tropical air and the potential for widespread, heavy rainfall, along with a corridor of gusty winds near the low-pressure center later this week.
As other no-named disturbances of tropical origins in the past have shown – such as the August 2016 Louisiana floods – it doesn’t take a bona fide tropical depression or storm to cause big flooding issues.
We’ll keep an eye on the trends for brief tropical development by mid-week, but either way the upshot will be a wide stretch of real estate impacted by heavy rains and the risk of numerous flash floods through the end of the week.
Elsewhere tropical development isn’t expected in the Atlantic basin this week.
Not looking forward to this. Even half of a Harvey flood is serious business. *sighing* ☔
At least the CAG has been tamped down. This could be a whole lot worse.
Ty Mr. Lowry 🌺