Houston wrapped up five very wet days on Saturday evening, as a weak cold front finally ushered an extremely moist air mass off to the east of the region, and stabilized the atmosphere. Before discussing out more sedate weather ahead, first let’s look back at the five-day rain totals, and whether the flood scale we implemented this month was effective.

This map shows rain totals for the last seven days, and encapsulates the rain event that lasted from last Tuesday through Saturday. The greatest rain totals fell near Sugar Land, in the southwest part of the region, Kingwood, to the northeast, and Beaumont. One area near Sugar Land received 18+ inches, while the bright purple areas indicate 14+ inches. Overall, most of the Houston metro area received 6 to 12 inches of rain. Interestingly, one does not have to go all that far from the metro area to find a region, in this case Brenham, that received less than 2 inches of rain. This gives you some idea of the challenge of forecasting these kinds of precipitation events.

Flood scale

We introduced a flood scale to provide readers with a general expectation about upcoming flood events. Initially, we rated this five-day event as a “Stage 2 flood,” but after the intensity of Tuesday’s storms—which turned out to be the worst of the five days—we bumped these floods up to a Stage 3 event on Wednesday.

This feels about right in hindsight, given the five-day accumulations over some locations, but we’d welcome any comments or thoughts you have about the scale as we continue to refine it. Thursday night’s hail was also notable, and Matt may have some more to say about that the next day or two. Now, on to the forecast.

Monday

After last week’s storms, this week’s weather will be somewhat anti-climatic. Monday should be especially nice, with mostly sunny skies, highs in the low 80s, and for May, fairly dry air. Some clouds, along with southeast winds, return tonight with lows in the mid-60s. This would have been a great weekend day.

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We’re almost there, Houston. Just one more round of showers and heavy rain today, and then we can put the several five days of intermittent heavy rainfall and storms behind us. Fortunately, in comparison to our recent weather, today’s storms do not look too serious beyond their potential to disrupt outdoor activities—and I know there are plenty planned as we’ve been asked about weddings, baseball games, camp-outs and more.

Showers and thunderstorms today will be driven by a disturbance moving up the Texas coast, combined with an extremely moist atmosphere. The best chance for storms today will occur south and east of I-69, near the coast. (Under some scenarios, the heaviest rainfall occurs near Galveston Bay, and under others, it occurs offshore). Generally, I think inland areas—those on the north and west side of I-69 will probably see about 1 inch of rain or less today, while people closer to the coast will see 1-2 inches. Isolated amounts of 3 inches or higher are, unfortunately, possible. The good news is that rainfall rates appear to be more restrained today, so we don’t anticipate any of the crazy 3+ inches per hour we saw over the last four days, which rapidly flooded streets.

Storms will likely develop between 10am and noon across Houston, with a general west to east motion that pushes them out of the metro area between 3pm and 7pm. Good riddance!

After this mess moves out, we should see clearing skies tonight, with rather pleasant weather for Sunday and Monday, with highs in the low 80s and overnight lows in the 60s. It will almost be nice enough for you to forget that June is only a couple of weeks away.

After an ugly round of storms moved through Houston on Thursday night and Friday morning, the region has seen some general clearing today. This is good because several waterways, including Clear Creek in the southeastern part of the metro area, crested above their banks this morning and need some time to recede. Alas, this multi-day rainfall event is not quite over.

Based upon the stability of the atmosphere, we can reasonably expect a mostly quiet evening and probably most of Friday night before storms return to the region on Saturday. There’s not a ton of agreement among the models, but generally we think most of the action will probably be between I-69 and the coast, over Brazoria, southeastern Harris, and Galveston, Chambers, and Liberty counties. (Our concern is that this is where the aforementioned Clear Creek lies). For most of this area, beginning around sunrise or a few hours later, we expect perhaps 1 to 3 inches of rain. That’s not overly concerning, but we can’t rule out a few isolated areas with 4 to 5 inches. For central and northern parts of the region, we expect lesser amounts of rainfall, with perhaps 0.5 to 2 inches of rain. The good news is that none of the forecast models are predicting some of the extreme, 3+ inches per hour rates we’ve seen earlier this week that rapidly led to street flooding.

We will see some thunderstorms with Saturday’s rainfall, but at this time we do not anticipate the kinds of widespread, severe thunderstorms, with hail and rampaging winds, that the region experienced Thursday night. And the storms should mostly develop after sunrise, so hopefully we can all get a good night’s sleep for a change.

Depending on which model you choose, rains should end from west to east, sometime between noon and early Saturday evening. We still expect drier air, with lower dewpoints and sunshine on Sunday, all of which should help begin to dry out the area.

Good morning. We hope everyone is safe and doing well this morning. It has been a rough 12 hours in Houston and the surrounding area. From hail to non-stop lightning to flooding, I think we have all had enough. Numerous schools are closed this morning, including Houston ISD. Total rainfall over the last 24 hours has ranged from anywhere between 1 and about 7 inches across the region. On average, most places did 2 to 5 inches or so.

Flooding update

There are still numerous spots around the city and suburbs dealing with high water and street flooding. An areal flooding warning is in effect for almost the entire metro area through 10:30 AM.

There were still a number of bayous that were either near bankfull or out of their banks. Most were southeast of the city, particularly along Clear Creek which is experiencing minor flooding between Pearland and Clear Lake. Spring Creek to the northwest is still rising a bit and is out of its banks at Hegar Road, as is Little Cypress Creek at Becker Road. Armand and Hunting Bayous have crested and will continue to slowly fall. Halls Bayou has as well, but that I-45 area near Mt. Houston is still a mess.

Trucks going the wrong way on I-45 feeder just trying to get thru the flood. Not sure why? #abc13 https://t.co/9BScHTxDNs pic.twitter.com/ctibnPN3ej

— Courtney Fischer (@CourtneyABC13) May 10, 2019

You can view the latest status of bayous and creeks at the Harris County Flood Control website. On the upper left, just check the dial for “Channel Status.”

In terms of the larger rivers: The West Fork of the San Jacinto is rising at US-59 near Humble.

It will probably crest later today around a foot lower than we saw on Tuesday.

The Brazos will experience moderate to major flooding and is going to crest later this weekend about one foot or so shy of record levels at Rosharon. It will crest sometime today or into the weekend slightly less impressively, but still in solid moderate flood at Richmond. And it is going to stay high for a good time to come.

The bottom line: Be cautious this morning if you are out and about as there are a number of locations still flooding. But in general, conditions should slowly improve through the day.

This morning

Alright, let’s get into the forecast.

Radar as of 5:35 shows that the majority of the rain has shifted well east of the area. We are seeing new showers develop to the west and south of Houston. This isn’t unexpected, but it may mean some additional downpours over the next few hours, particularly along and southeast of US-59 from Victoria through Houston. There has been flash flooding in Galveston

These showers should gradually diminish and shift off to the east through the morning. There is simply very little “energy” left in the atmosphere over us to sustain new storm development. We’re tapped out after last night. So the trend should continue to be toward a drying one this morning.

This afternoon

Other than a handful of scattered showers in parts of the area, the rest of today looks quiet. We will have a chance to dry out a bit and clean up any mess left behind.

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