In brief: A high-end EF-1 and a low-end EF-2 tornado were confirmed today from damage surveys conducted by the National Weather Service northwest of Houston. The first occurred in Riata Ranch. The second was in Klein. Additional damage surveys may still be done to check for other tornadoes or to fine tune these paths.

Two confirmed tornadoes

The NWS Houston office went out and did the dirty work on damage surveys from Monday’s tornadoes. They confirmed two so far. The first was a high-end EF-1 that had maximum winds of 105 mph (corrected from the above graphic) in Riata Ranch and a path length of 2.6 miles. The second was a low-end EF-2 that hit the Klein area, with maximum winds of 115 mph (corrected from the above graphic) and a path length of 3.8 miles. I believe these are the first tornadoes in Harris County since just after last Christmas.

Riata Ranch tornado

The Riata Ranch tornado touched down just after 1:20 PM on Monday. For those unfamiliar, Riata Ranch is just east of Barker Cypress Road just south of 290. A radar capture from 1:23 PM on Monday shows the tornado developing. The first touchdown point occurred in Towne Lake, just off Tuckerton west of Barker Cypress.

Following radar, you are able to see the rotation track to just west of Barker Cypress at 290 by 1:26 PM. It seems that a debris signature (TDS) becomes evident on radar between 1:26-1:29 PM, which indicates a pretty healthy tornado in progress. This occurs as the original circulation begins to broaden out crossing 290. At this point, the tornado was lifting.

Indeed, the NWS found that the tornado dissipated around 1:28 PM at 290 and Barker Cypress.

Overall, the TDS on this one was very impressive, usually only the type of TDS I’ve seen in typically stronger tornadoes. This is likely indicative of the densely populated area it struck.

Klein tornado

We got a 10-to-15-minute break before the same supercell dropped another tornado. Around 1:41 PM, a new tornado dropped just east of Cutton Road along Louetta Road.

This one did not show quite as strong a TDS as the Riata Ranch tornado, despite being a little stronger. Nuance is a thing. It didn’t take long for it to show up, however, which happened around 1:47 PM. Notably, the debris signature from the Riata Ranch tornado does not appear to have dissipated entirely around this time, but it does show up nicely.

Notably, when you’re looking at these tornadic debris signatures, remember a radar beam doesn’t go out flat. It aims up, so at this distance, about 49 miles from the HGX radar in League City/Dickinson, we’re sampling what’s occurring about 3,500 feet up. So this indicates that the tornado was lofting debris several thousand feet up in the atmosphere. Overall, this was a very impressive event for Houston. We see tornadoes rather frequently here, but not usually this strong. Of the 78 tornadoes confirmed in Harris County since 2000, only 6 have been F/EF-2 or stronger. The Klein tornado now makes seven.

In brief: Today’s post dives into the very warm Gulf waters, which have been driving this month’s anomalously warm temperatures. We also look ahead to exceptional weather for Thanksgiving and a soggy weekend. Also, I review how that ‘crazy’ long-range holiday forecast I made 12 days ago held up. Am I a turkey?

A November to remember

With less than a week to go in the month of November, the city of Houston’s average high for this month has been 80.3 degrees (normal average high for the month is 72.6 degrees). Now we are going to come down off of this a little, because after today our highs for the remainder of the months will be closer to 70 degrees than 80. But still, it’s been hot. We had 10 days in the middle of the month where every day had a high of 83 degrees, or above.

As always with climate and weather there are no simple answers, but I think one main driver of our anomalously warm November is the Gulf. For much of this month we have had a southerly flown off the water, and that has led to warmer days and nights. Let’s take a look at the current map for sea surface temperature anomaly in the Gulf, which simply means how much warmer (or cooler) the surface is than usual. Note the temperatures in the map below are depicted in Celsius, rather than Fahrenheit.

Surface temperatures right along the shelf of the Gulf, by the Texas and Louisiana coasts, are running 5 to 8 degrees Fahrenheit above normal. That’s really significant, and it helps explain why we’re having trouble cooling down closer to temperatures more typical of this time of year. This heat also extends below the surface. The graphic below depicts “ocean heat content,” which essentially includes measurement of surface and deeper waters in the Gulf.

Now the graphic is a little busy, but essentially the blue line represents “normal” heat content for the last decade, and the bright red line shows what’s happening this year. And the current total heat in the Gulf is higher right now than at any point over the last decade. So there is a lot of hot water out there. I’m sure there are complicated reasons for this, but it is hard to deny that this kind of heat is one consequence of a warming planet. We are finally going to cool down this week on land because the overall flow will shift to come from the north, rather than the south, keeping the warmer air over the Gulf offshore.

Tuesday

After Monday’s storms, including a couple of tornadoes, quieter conditions have prevailed across the region. Following the passage of a weak front, drier air will slowly seep into the region from the northwest today, bringing gradually falling dewpoints. However there just is not much oomph with this initial front, so most of Houston is likely to see high temperatures in the vicinity of 80 degrees today. In contrast to our usual daytime pattern, highs will likely be a little warmer closer to the coast, whereas areas further inland remain in the upper 70s, more influenced by the front. You’ll notice the lower humidity by this afternoon, and this evening will feel mighty pleasant. Skies will be clear. Lows tonight will drop into the 50s for most.

Wednesday

A secondary push of colder and drier air, this time with more impetus behind it, arrives on Wednesday. This will lead to a day with mostly sunny skies and a high temperature in the neighborhood of 70 degrees. Winds will be gusty in the middle of the day, up to 20 or 25 mph as the northerly air blows in. Our humidity will drop even further, with lows on Wednesday night falling into the 40s for most locations away from the coast.

Thursday

After a chilly start, Thanksgiving will be a beautiful, sunny day with highs generally in the upper 60s and light winds. The National Weather Service, this morning, is actually forecasting a high of 68 degrees at both Bush Intercontinental and Hobby airports. I’m not going to brag—as a forecaster it pays to be humble, because you’re always going to miss some shots—but remember when I made that long-term Thanksgiving forecast 12 days ago? You guessed it, I predicted a high of 68 degrees. I was wrong about the rain chances, they’re not 30 percent, they’re closer to zero. As for the partly cloudy skies predicted then, I would go with mostly sunny instead. Lows on Thursday night will be similar to Wednesday night.

Friday

The onshore flow will kick in Thursday night or Friday morning, and this will set us on a warming curve. Friday will be partly to mostly cloudy, with highs around 70 degrees. Lows on Friday night will only drop into the 60s. Some slight rain chances return Friday night.

Saturday and Sunday

An approaching frontal system from the west is going to bring wetter conditions this weekend. Generally, I think we can expect highs in the mid-70s on Saturday, with fairly widespread, light to moderate showers. It won’t be wall-to-wall rain, but beginning Saturday morning we’ll see healthy rain chances that persist through the weekend. At some point a front is likely to move into the area, and this likely will occur on Saturday night or Sunday morning, some time. Sunday, therefore, will probably be cooler, in the 60s, with ongoing 60 to 70 percent rain chances. At this time the weather pattern appears unlikely to support severe thunderstorms, but we shall see.

Next week

I expect rain chances to linger after this front, probably through Monday and into Tuesday, even as we see gradually falling temperatures. We should see a few colder days next week, with highs perhaps only in the 50s, and lows in the upper 30s or 40s. I don’t think a freeze is in the cards, but Houston is definitely going to feel a lot more like winter. We’ll keep a close eye on the forecast to see how it develops, and alert you if a freeze is likely.

Fundraiser

We’re into the final week of our annual fundraiser. Your support this year has been tremendous, and we really appreciate any help you can give. More information on how to donate or purchase merchandise can be found here.

In brief: The National Weather Service has confirmed the formation of a tornado in northwest Harris County this afternoon. More storms are expected over the next couple of hours before a brief lull, followed by a broken line of storms later this evening. Please be weather aware!

Hi everyone. Just wanted to jump in with a quick post this afternoon as showers and thunderstorms to the west and north of Houston have been a little more intense than anticipated. We already have seen a couple of tornado warnings earlier today, one to the west of Harris County, and another near Cypress and Jersey Village. As of 1:38 pm CT today, the National Weather Service confirmed a tornado near Willowbrook, moving to the northeast. The warned area is shown below:

For the most part we think these storms will continue to drift north, away from Houston later this afternoon. However, we cannot rule out some lingering storms (mainly north of Interstate 10) during the afternoon hours. And given what we’ve seen so far, some of these storms could be capable of producing tornadoes.

There may be some clearing later this afternoon and evening before a broken line of storms associated with a front moves through the area, from northwest to southeast. Our latest modeling indicates this line should reach areas such as Katy and The Woodlands in the vicinity of 8 pm, downtown Houston around 10 pm, and the coast after midnight. More severe weather will be possible as these storms move through. Calmer conditions are expected from Tuesday onward.

In brief: In today’s post we talk about the potential for storms this evening in Houston as a weak front sags into the area. A second push of colder air will make things feel festive on Thanksgiving Day. And we’ll see the return of a moderately warmer pattern with higher rain chances this coming weekend.

We begin today’s post with a little bit of housekeeping …

A few words on our app

Our app—which remains completely free and does not track your activity, in other words we do not monetize your data—is now a few years old. We went through some growing pains this year as both app platforms changed things up. Honestly, keeping up with everything in app-land is a lot, and so I’m glad we’ve got Dwight Silverman and Hussain Abbasi to manage all of it. There have been a fair few bugs and issues we had to slog through earlier this year, but I’m happy to report that everything has been working really well for the last couple of months. But don’t take my word for it, here’s a comment sent in by Lily Yee last week. We’re sharing it with her approval:

Hey! I just opened this app for the first time in several weeks (full honesty) and I was SHOCKED by the noticeable, significant improvement in loading speed & reaction time. To your web dev and design team – great job! 🙂 it makes a real difference on the usability. I’ll be putting this app on the front page of my phone screen now!

So if you haven’t downloaded the app, please do so now by clicking here. It’s fun, and free, and even sometimes the forecast is accurate.

Fundraiser

We’re now into the final week of our fundraiser, and I mentioned our app above because the reason we’re able to provide it, and update it, and keep it junk free is because of contributions from our readers. Your donations and purchase of merchandise now allow us to plan for next year. We want to continue iterating on the app (more on this soon) as well as make some other major upgrades like improving the distribution of our newsletter. If you can help out, please do so here.

Monday

Our brief foray with cooler fall weather on Sunday has ended, with this weekend’s front moving back onshore as a warm front overnight. Winds this morning are light, from the southeast, with temperatures around 70 degrees. Accordingly, today will be rather warm, with highs in the low 80s despite mostly cloudy skies. We are going to see scattered (mostly light) showers during the daytime along with very humid air. By this evening, likely around 7 to 9 pm, a broken line of storms associated with a cold front will develop to the northwest of Houston. This line will slowly advance into the city during the late evening hours, and push off the coast after midnight. Damaging winds will be possible with this front, perhaps gusting up to 50 mph, with potentially some hail. Overall rain accumulations will vary widely, but most of us should pick up between 0.25 and 0.75 inch.

Tuesday

The initial push of cooler air with with this front will be fairly weak. As a result I expect highs of around 80 degrees on Tuesday, with mostly sunny skies and lower humidity. Low temperatures on Tuesday night should drop into the 50s.

Wednesday

A secondary push of colder air arrives overnight, into Wednesday morning, and this will result in breezier northerly conditions. Winds may gust out of the north up to 20 mph on Wednesday. Expect sunny skies and highs in the upper 60s. Lows on Wednesday night will drop into the upper 40s in Houston, with cooler conditions for inland areas.

Thanksgiving

We’ll start the day clear and cool, and skies will be sunny throughout the day. Really, we have no weather concerns, with light winds expected and highs generally in the upper 60s. Lows on Thursday night will drop to around 50 degrees, with cooler conditions for inland areas.

Friday, Saturday, and Sunday

The onshore flow resumes on Friday, and we are going to enter a period of mostly cloudy skies and increased rain chances by Saturday morning. High temperatures through Sunday should be in the low- to mid-70s, with modestly increasing humidity levels. Overall I think the area will pick up 1 to 2 inches of rainfall on Saturday and Sunday. If you have outdoor plans we’ll keep a close eye on the forecast for you. At this point I think showers will be intermittent rather than wall-to-wall, but we don’t have a good handle on the details yet.

Next week

At some point, perhaps on Monday, a stronger front should push into the region. This is likely to bring some colder conditions, with lows perhaps down to around 40 degrees next week. It does appear as though the first week of December, which is the first week of winter as well, will probably feel decidedly winter-like in Houston. But for now the forecast is still a bit uncertain.