Matt Lanza

In brief: There will be some showers this morning south and east of US-59 to the coast. Some thunder is possible. No severe weather is expected. The rest of the forecast through Monday and Tuesday is quiet and turning hotter.

We have a few showers southwest of Houston that will push in this morning. The steadiest rain will be south and southeast of the city, areas that saw a bit less action yesterday. We then clear out and dry out for later and tomorrow, Sunday, and Monday. Highs will nudge into the 90s with lows slowly increasing through the 70s into next week.

Trying to make sense of Thursday

This will be a different post than typical. I want to walk through what happened yesterday from a forecaster’s perspective. About 750,000 customers remain without power this morning, and because of the extensive, widespread damage, this number will very slowly decrease today and tomorrow. Some may be without power until next week.

So how did we get here? As a refresh, here is Eric’s post from yesterday morning. We were all really focused on the threat for heavy rain, and with the high risk in place yesterday to our north, that shouldn’t be a surprise. In fact, 4 to 5 inches of rain did fall as expected, basically north of highway 105 through Conroe.

Eric did note the severe weather and correctly underscored the chances of wind and an isolated tornado. The Storm Prediction Center had the right idea on severe weather yesterday too. But again, I think most of us the significant messaging was heavily focused on the rain.

Through most of yesterday morning, not a whole lot seemed to change. Eric, Dwight, and I met up for lunch at a Pappas BBQ but not the one we originally planned on, which, thanks Apple Maps. Or Google Maps. Who’s to say? Anyway, we touched briefly on the day’s weather but were not particularly concerned about anything else happening. We checked radar while leaving and all looked good.

I got back to my desk and noticed a few people pinging me about a Reed Timmer tweet discussing rain-wrapped tornado potential in southeast Texas. Reed’s a good guy and a very smart meteorologist, but he also has tons of enthusiasm. His brand is to dominate and never stop chasing. My first reaction admittedly was to roll my eyes, but then I checked out the HRRR model, one of our hourly updating high-resolution weather models. Indeed, it lit up with supercells by 2 PM. But it was 2 PM. And there were no supercells.

So clearly it was overdoing it, and it would be necessary to watch subsequent runs to see what changes, as well as radar to observe the evolution of the storms. I decided to look at some other data, and I was surprised to see that despite clouds, haze, and mist (or even a heavy drizzle at times), the atmosphere was extremely unstable over the area.

And when you would dig deeper into the models, everything pointed to severe potential. But we also just went through this a few days ago with a major hail threat that basically failed to materialize with any consequence in Houston. In that case, we had the same situation in theory: Impressive instability and an atmosphere primed to rock. As a meteorologist, you look at this two ways: We just came off a semi-bust and you need to make sure you are more confident in something than normal before pushing it, and secondly you also can’t deny that the ingredients were there. A tornado watch was issued, which was a little surprising, though given the parameters there was no good reason to argue much against it.

When I looked at model data, it appeared that any supercell risk would track from the southwest to northeast. I even highlighted a cell around Spring at about 4:25 that I thought was showing signs of trending toward something more meaningful. I went to pick up my oldest from school and came back intending to help him do some homework. Even by about 5:10 or so, it seemed pretty straightforward: A line of severe storms with gusty, maybe localized damaging winds was moving through Brenham and toward Waller County, and we’d probably get it through by 7 or 8 PM and that would be that.

Things began to change quickly about 15 minutes later. It was evident that rotation had begun to develop on the leading edge of the bowing line near Bellville. And it seems likely that a tornado may have been put down just east of there shortly thereafter. That is not necessarily uncommon. It’s often how we get our tornadoes locally, but it’s usually brief and disappears after 5 to 10 minutes. And indeed, the rotation weakened some, but at 5:35, it flared back up again, just west of FM 359 to the east of Bellville. Thereafter, it absolutely exploded near Pine Island and just south of 290 in Prairie View. By 5:40 to 5:45, we clearly had a problem.

I have been in Houston for about 12 years as of this week, and I cannot recall seeing this type of velocity signature (the right-hand panel) show up in this area. When you see this as a meteorologist, it either means a violent tornado is underway, or destructive winds are probable. At times, it looked like you could pick out a debris signature on radar that would essentially confirm a tornado, but it never took off, which led me to believe that this was becoming a major straight line wind event.

I had been texting a bit with Justin Ballard, the Houston Chronicle’s fine meteorologist earlier about the tornado watch. We both expressed some skepticism it would produce. He texted me at 6:07 in the middle of this saying, “Yeah, that doesn’t look like a bad decision after all.” Yes, many of us talk to one another. Yes, we occasionally have opinions on things.

Anyway, this continued to march east-southeast and slowly expand. At this point, it becomes straightforward: Monitor it and warn and clear. I had posted to Twitter in a tone I very, very rarely ever use. I don’t throw around language like “Treat this like a tornado” very often. We had gotten very few damage reports up to that point, but the radar was indicating 110 mph winds down to about 2,500 feet. By 6:23 PM, radar showed 120 mph winds down below 2,000 feet approaching Oak Forest. Does all that reach the ground? No. But a lot of it can. It also made me gravely concerned for the downtown high rises.

We’ll find out more today and tomorrow about specifics on damage and what was a tornado or straight line winds. Whatever the case, this was one of the most ferocious storms I’ve ever seen. This was a smaller scale version of what occurred in Iowa a few years back, when they had 140 mph winds down to about 1,000 feet but over a wider area. Whether or not this gets classified as a derecho will remain to be seen. I think it probably falls just short of that metric because of some discontinuity in the damage report path, but honestly, does it matter? It will take time to pick up from this one, and we hope our readers are safe. A major kudos goes out to the many media meteorologists and NWS meteorologists that assisted in keeping as many people safe and informed as possible. Saving lives is rarely a literal thing for a meteorologist. I am thinking that it was for many last night.

I’ll close with a bit of a sobering note: Hurricane season begins in about 2 weeks. What many of you witnessed last night would be experienced not over a few minutes but over several hours over a large area if a truly potent hurricane found its way into the Houston area. By living in this region, you have to accept the risks associated with that. We know a lot about flooding. Most of us know about surge. Very few knew about wind and what it’s really like. Many do now. Use this experience to inform your preparation for hurricane season just in case. Houston has been through an absolute meat grinder of weather disasters in the last 10 years. Candidly, it sucks, but we should know enough now to prepare for the next one.

In brief: If you have clear skies and minimal light pollution, look to the north for a chance that you may see the aurora borealis (or northern lights) here in Southeast Texas (Friday night, the 10th).

We’ll keep this brief. A massive, if not historic solar storm has unleashed a barrage of solar flares toward Earth. Those arrived today, the strongest solar storm in at least 20 years to impact us. We have seen reports all over Europe of the aurora being visible. Not just visible…VISIBLE. Those reports have spread into the U.S. now, with much of Georgia, parts of Mississippi, Mobile, AL, and now Pinehurst and The Woodlands and Lake Conroe reporting the aurora.

The aurora can be fickle, so there is no guarantee you will see it everywhere tonight, certainly not in the city of Houston where light pollution is likely too much to overcome. However, if you have the means and time to get out and look north, this may be a once in a lifetime opportunity here in Southeast Texas. Please send us pictures as you’re able.

In brief: Quiet weather, (hopefully) less haze and smoke, and lower humidity will welcome us today and most of Saturday. Scattered to numerous showers and storms will bring a heavy rain chance back to the area on Sunday and Monday. We will be watching for flooding risks again to the north of Metro Houston.

I just want to start with a quick thank you to all that replied to our call for assistance earlier this week for our partners at the University of Houston working on weather messaging research. Nearly 200 of you responded, which is both amazing — and overwhelming! The small team of researchers at UH is working hard to get to everyone who replied. They should have more than enough response now to hopefully generate some interesting and useful results. Once again, you’re all awesome, so thank you!

Heavy rain update

While most of Houston saw little to no rain last night, areas to the north and west were clobbered with large hail or heavy downpours. There was another 1 to 4 inches of rain on the northern end of Lake Livingston. At this point, it does not appear that will do much to the Trinity River situation (which continues to slowly drop). But we’ll await updated forecasts later today. Meanwhile, the Brazos will begin to crest from north to south this weekend into next week.

The crest should reach Rosharon by about Monday and then West Columbia by Tuesday, with minor to moderate flooding, which primarily affects the lowlands and perhaps a couple roads near the river. This is not currently expected to get worse.

Today

Update (10:05 AM): Some showers have developed across Wharton and Jackson Counties and will spread eastward through the morning. Brief heavy rain is possible, and a shower can’t be ruled out in Houston either.

Good news today. Air quality should improve. Yes, the last couple days have seen smoke from a lot, I mean a *lot* of agricultural fires in Mexico and Central America. It has degraded air quality and everyone’s mood. With a breeze today pointed offshore, that should hopefully push a lot of this smoke back south of here. Hopefully last night’s rain helped too. I won’t promise a super clean air quality day, but we are starting off much better than yesterday already.

Will this end our streak of 90 degree-free days? Probably not. But it may be close. Drier air heats up more efficiently than humid air, and there may be just enough to push some of us over 90 today, particularly south of I-10. Maybe bet on Hobby Airport and not Bush Airport.

Saturday

This should be a mostly quiet day. Maybe a sprinkle or shower. But otherwise clouds, sun, still not terribly humid or hot. Morning lows will be in the 60s to near 70, with daytime highs in the mid-80s.

Mother’s Day & Monday

The word to your mother will be rain this year. Unfortunately we continue to see a soggy picture being painted for Sunday. I don’t think the entire day will be a washout everywhere, but an umbrella will be a required accessory for church or brunch or wherever your plans take you. Scattered to numerous showers and thunderstorms are likely on both Sunday and Monday. For the majority of metro Houston, most of the rain should be manageable. Some ponding or a stronger storm or two are possible. At this time, we don’t expect much worse than that. Again, that’s for most of Houston.

That said, atmospheric moisture is near the top of the charts for this time of year, which means that we could be talking about heavy rainfall rates in spots. If those rains end up north of I-10 in vulnerable areas up in Montgomery, northeast Harris, or Liberty Counties and points north, we may have flooding issues again. For now, let’s call it 1 to 3 inches of additional rain, with lower amounts possible south and higher amounts possible north. Keep tabs on the forecast this weekend. We will have at least one more update later tomorrow or Sunday morning with the latest.

Rest of next week

Quieter weather should follow for Tuesday or Wednesday before more storm chances return perhaps Wednesday night or Thursday. We have an opportunity to hit 90 on Tuesday, but then our next realistic chance won’t come until next weekend.

In brief: Morning rain has thus far been manageable, but repeated rounds of thunderstorms along and on either side of I-10 will likely cause ponding and street flooding in spots this morning and afternoon. Flood Watches remain in effect through evening.

Happening now

One round of heavy rain and storms has exited to our east. Rain totals from that round were manageable in the Houston area and most points north to Conroe. A couple flash flood warnings were needed north of Lake Livingston and back into Huntsville, where totals approached two inches. Now, we’re seeing a west-east line of storms from northern & central Harris County back past Columbus.

Rest of today

This line of storms will likely “train” west to east through the morning and early afternoon. This means repeated rounds of storms basically within 20 miles of either side of I-10. For now, there are enough gaps in between downpours to keep things mostly just annoying and not troublesome. If that continues like that the rest of today, we’ll be fine; yes there will be roadway ponding or localized street flooding but probably nothing much worse.

Eric and I have been wary about things this week because, frankly, most model guidance has struggled. But in general, things seem to be doing what was expected. So, thunderstorms this morning on both sides of I-10. Look for these to continue into early afternoon. Some scattered activity may pop up north of Harris County this afternoon, and we’ll watch for localized downpours up that way. The NWS Flood Watch continues through evening, and our Stage 2 flood alert will continue with that as well. If, for some reason this band of storms shifts farther to the north, it will not take a lot to begin flash flooding. And if for some reason, the rains over Houston remain heavy with fewer breaks, we could see more widespread street flooding. So that’s why we’ll maintain that Stage 2.

Editor’s Note: The National Weather Service Weather Prediction Center issued a discussion while I was editing this post, suggesting that heavier rain over the Houston area was likely through afternoon and could lead to more widespread street flooding. We’ll continue to watch this through the day.

Totals, as you can see from above should be generally 1 to 2 inches, with isolated higher amounts possible. Lower amounts toward the coast and perhaps to the north. Obviously, it’s been pretty rough this week in terms of forecasts and impacts, so continue to monitor the situation, and we’ll post later if anything seriously changes.

Conditions should improve this evening.

Monday and beyond

We finally begin to unwind this disrespectful weather pattern. Temperatures will begin to heat up, and we still expect low to mid-90s into midweek. Rain chances won’t be zero, but they’ll be much lower than they’ve been in recent days.

Even though the rain will quiet down, river flooding will continue this week. One river we have not discussed much is the Brazos. Things have been fine there, but the river is likely to continue rising all week and may even approach moderate flood levels by late in the week.

Beyond Friday, it’s a bit uncertain still, but assuming the river hits 68 feet or so, we’ll begin to see the flood plain get inundated, requiring the relocation of cattle. We’ll monitor this in the coming days; thankfully there’s time to prepare.