Harvey late night: Water levels rising across Houston metro area

Monday, 12:30am CT—Nearly every bayou, river, stream, and waterway in and around Harris County has reached the top of its banks, or exceeded them. Flooding is occurring in multiple neighborhoods across the region, and worse is still to come. It is anything but hyperbole to say this is the most catastrophic flooding event in the city of Houston’s history. Tropical Storm Allison, a 500-year-flood, held the title for just 16 years.

This radar image (below) from around midnight shows what the region is up against tonight, and in the coming days. As the center of Tropical Storm Harvey drifts toward Matagorda Bay, it is producing a huge, 400-mile arc of showers that stretches all the way from south of the Texas-Mexico border into The Woodlands. This is an awesome, terrifying feat of nature—a freight train laden with moisture bound for the upper Texas coast.

Radar image at midnight, Sunday. (Intellicast)

Truthfully, we don’t really know what will happen next. Some drier air has moved into the southern half of the region from the west tonight, and this has led to some drying behind the line of showers, from El Campo to Galveston. Some of the short-term, high resolution models suggest the heavier activity will now slowly move off to the northeast of Houston tonight, toward Beaumont and Western Louisiana. (Beaumont is having an historic rain event too, by the way). This may offer a short reprieve for parts of Houston, and truthfully anything is welcome.

But with Harvey’s center so close by, we can almost certainly expect more to come. Tonight, western areas of Houston, including Katy, Cinco Ranch and other communities along the Sam Houston Tollway, picked up 7 to 10 inches of rain in just six hours. Who will be hit so hard next? We probably will have to worry about these mega-rain-bombs for another two or three days, perhaps into Wednesday, or Wednesday night. And what will that mean for Houston, its bayous, and its increasingly beleaguered citizenry?

Truly, we don’t know what happens next. This is uncharted territory for Houston in terms of flooding and potential disruption to our communities. Certainly, some help is on the way from the state and federal government. But in the meantime, be kind to your neighbors. We have seen incredible acts of valor and bravery and heroism during these last 36 hours from common, ordinary people. We have saved lives, and made the lives of others just that tiniest bit easier. We will need much more of this to make it out the other side.

Posted by Eric at 12:30am CT on Monday by Eric

Another very wet night on tap for Houston

Sunday, 8:40pm CT—As darkness descends upon Houston, another very wet night has already begun for the region. So far this evening, the heaviest rains have fallen across the western part of the region, including the Katy area. As much as 6.5 inches of rain have fallen near Cinco Ranch from 5pm to 8pm. A flash flood emergency is continuing for pretty much the entire Houston area tonight.

Tropical Storm Harvey, at sunset over Houston. Sunday. (NOAA)

Addicks and Barker

These rains have occurred near, and over the massive Addicks and Barker reservoirs on the west side of the city. Earlier today, the US Army Corps of Engineers said it would have to make controlled releases into Buffalo Bayou (which already is beyond flood stage) in order to prevent a more catastrophic release later next week. “This flood event will exceed the 2016 Tax Day Flood elevations,” said Col. Lars Zetterstrom, Galveston District commander.

It seems probable that some homes near Clay Road and Eldridge, and in the vicinity of the Westpark Toll Road and Highway 99 will see water remain in homes for up to two months. That is not a misprint.

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Addressing the Zombie Hurricane Harvey scenario

Today, there has been a lot of chatter on social media about the potential for the remnants of Harvey to move offshore into the Gulf of Mexico by around Monday, whereupon it might strengthen into a hurricane again and make a second landfall over Houston. This is obviously a scary scenario, but frankly it’s not one we’re losing too much sleep about here. The main threat for Houston remains heavy rains and inland flooding. But let’s discuss this anyway, because we’ve had a lot of questions regarding it.

For readers who been with us a few days, you’ll recall that we’ve been discussing the “Euro special” scenario since Thursday. The idea is that a drifting Harvey would wander southeast this weekend, and move back over the Gulf of Mexico. That seems increasingly likely to occur, although it’s far from locked in. Even with the European model, which has most consistently held to this solution, only about two-thirds of the ensemble members have the storm offshore on Tuesday.

European ensemble members for Harvey’s location on Tuesday evening. (Weather Bell)

While the center may move offshore for a day or two, the fact remains that Harvey no longer has an inner core, and what remains of it will deteriorate further while it is over land Sunday and at least part of Monday. This, along with its proximity to land, should limit intensification. In the official National Hurricane Center forecast released Sunday afternoon, hurricane scientists predicted that it may attain 45 mph winds offshore, but was not likely to strengthen further.


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Late Sunday afternoon Harvey forecast update

Good afternoon. Rain rates today have been more manageable in the area. We’ve even had reports of sunshine in spots. Over the next few hours, the weather is going to likely deteriorate once more. Current problems will continue and new ones will crop up, but we feel that we will probably see less rain overall tonight than we did last night in the Houston area. That being said, tonight’s rains come with a bit more uncertainty than last night’s. Let’s explain.

Now

Harvey is centered about 25 miles from Victoria. This is further east than Harvey was at this time yesterday. The setup has changed a bit, with a weak boundary along I-10 and flow that’s directed more southeast to northwest from the Gulf.

What does this mean? It means that varying intensities of rainfall are likely tonight south of I-10. Again, this isn’t optimal, but my hope is that the rains will remain manageable south and southeast of Houston. Folks in those areas will need to stay alert and keep the guard up overnight, but rain totals (and the hope is VERY importantly, the rain rates) should be less than last night.

Overnight HRRR model projects the heaviest rains near Beaumont/Port Arthur and north of I-10 in Houston. (Weather Bell)

North of I-10,it’s similar, but with more rain and fewer breaks. Expect occasional 1-3″ per hour rain rates in those areas. This will exacerbate already near-record levels of flooding on Cypress Creek and other bodies of water north of Houston.

On average, I would expect 3-7″ south and 4-8″ north, but there is most certainly a risk of higher amounts in spots. The heavy rains near Port Arthur and Beaumont should add up to 5-10″ or more.

Tomorrow & Tuesday

Looking ahead, no new news to report. After tonight, rainfall will continue sporadically and heavily at times through tomorrow, similar to what we saw today, perhaps with a few less breaks though unfortunately. Harvey will emerge back out over the Gulf near Matagorda, and a Tropical Storm Watch was reissued from Sargent to San Luis Pass with the National Hurricane Center’s 4 PM advisory. Eric will have a post shortly on that aspect of the storm, but please, use your bandwidth to deal with the rain and flooding around Houston right now. That’s the issue we have to focus on.

We’ll have another post on the forecast this evening. Stay safe.

Posted at 4:25 PM Sunday by Matt