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Dolly's rains continue to inundate Texas and Mexico

By: Dr. Jeff Masters, 2:41 PM GMT on July 24, 2008

Tropical Storm Dolly continues plowing west over South Texas, dumping huge quantities of rain. Radar-estimated rainfall amounts as high as 25 inches (Figure 1) have already been reported, and Dolly will probably rank as one of the the ten rainiest tropical cyclones to affect Texas. At its peak, Dolly delivered five inches of rain per hour to the coast at landfall. AIR Worldwide insurance company estimates that the total insured damage from Dolly will run $300 million - $1.2 billion, mostly due to flooding and wind damage (total damage is typically estimated as double the insured damage, and would thus be $600 million - $2.4 billion). One bright spot to Dolly's rampage--the storm's rains brought an end to the moderate to severe drought gripping extreme South Texas, and will help with drought conditions along coastal Texas northwards to Corpus Christi.

Dolly's total damage is difficult to estimate at this point, because much of it has yet to occur. Dolly is dumping prodigious rains, thanks to its very slow forward speed of about 7 mph. The rains from Dolly may rival those of Hurricane Beulah of 1967. Beulah, a huge and powerful Category 3 hurricane, dumped up to 27 inches of rain inland, triggering major flooding throughout South Texas and Northeast Mexico. Beulah did over $1 billion in damage to Texas, due in part to failure of levees on the Rio Grande River. Considerable damaging flooding will affect South Texas over the next few days, as Dolly's rains continue to pound the state. However, the levees on the Rio Grande River are expected to hold.

Figure 1. Radar estimated rainfall from Dolly.

Figure 2. Rainfall measured during Hurricane Beulah of 1967. Beulah caused over $1 billion in damage to South Texas, mostly due to serious flooding from rains that totaled up to 27 inches. Image credit: NOAA.

Elsewhere in the tropics
The tropical wave (97L) off the coast of Africa, a few hundred miles west of the Cape Verde Islands, is now over cool water of 25°C. The wave still has a large circulation, but has lost all of its heavy thunderstorm activity. Until 97L can find some warmer water (which should happen by Saturday), there is little chance of it developing. Wind shear is expected to be around 15 knots on Saturday, which is marginal for development, and there is plenty of stable, dry air for it to contend with. None of the reliable computer models show development of this system.

The four reliable computer models are not predicting development anywhere else in the Atlantic for the next 7 days.

Last blog until August 6
With the tropics relatively quiet now, I'm going to take some time off and do some hiking in Colorado (I've spent the past 3 days blogging from the back seat of a heavily loaded rental car, driving cross-county!) The peak part of hurricane season is almost a month away, and if the behavior of the tropics in July is any indication, it will be a long and severe hurricane season. So, I'm going to get some R&R in, and let Bryan Woods blog for me while I'm gone. I will be keeping an eye on things, and can jump back in if anything nasty pops up.

Jeff Masters

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.