Heat continues toward a peak on Memorial Day, when highs reach the upper 90s

In brief: After a few mostly cloudy days we’ll see increasingly clear skies and this will help temperatures march upwards. We’ll go from highs in the low-90s today, to mid-90s this weekend to upper-90s by Memorial Day. After that a weak front will provide some modest relief.

Thursday

After a cloudy start we should see partly sunny skies this afternoon, and this should help to push high temperatures into the low-90s. Winds will blow from the south at 10 to 15 mph, with occasionally higher gusts. Once again, we should see some fairly strong storms develop in central Texas to the north of Austin. While these will propagate eastward, I expect them to remain north of Highway 105 once again, with no impact on the greater Houston metro area. Low temperatures tonight will only drop into the upper 70s.

Some severe storms will be possible, once again, far to the north of Houston later today. (NOAA)

Friday

A day very similar to Thursday, although high temperatures are likely to be a degree or two higher.

Saturday and Sunday

We’ll see mostly sunny skies this weekend, with high temperatures solidly in the mid-90s. We will be hitting our first highs above 95 degrees nearly three weeks earlier than normal, in case you were wondering whether this is typical weather for late May. It’s not. Nighttime lows remain sultry, around 80 degrees.

Wet bulb globe temperatures for this week. (Weather Bell)

Memorial Day

Everything comes together on Monday, sunny skies and the characteristic jump in temperatures associated with an approaching front, to push our highs into the upper 90s. If we look at wet bulb globe temperatures—a measure of heat stress in direct sunlight that takes into account air temperature, humidity, wind speed, sun angle, and cloud cover—we see the potential for an ‘extreme’ day in terms of heat. Please bear this in mind if you have outdoor activities planned.

Tuesday and beyond

We’ll see a slight chance of rain on Monday evening as the front approaches and moves through, but for now I don’t expect anything more than a dusting of showers. Highs next week look more reasonable, in the low 90s, with overnight lows perhaps in the mid-70s. We’ll also see some daily rain chances in the Wednesday through Saturday period, although they may be of the 20 percent daily variety. I’m not sure yet. In any case, the very end of May should see a bit of a return to normalcy.

Storms possible well north of Houston, with a cap likely holding over the city as heat continues

In brief: A dying front brings a chance of storms well to the north of Houston tonight, but for most of us the story remains one of heat. Temperatures will peak over the weekend, with Memorial Day looking especially hot.

Wednesday

Expect another warm day in Houston, with highs of around 90 degrees due to mostly cloudy skies. It will be a little windier than Tuesday, with southeasterly gusts up to about 20 mph. With the humidity, it will feel plenty hot outside during the daytime hours before lows drop to about 80 degrees tonight.

There is a healthy chance of storms well to the north of Houston later today and tonight. (NOAA)

For areas north of Houston, and by this we are probably talking about locations north of Highway 105 in Montgomery County, there is a chance of storms later this evening and during the overnight hours as a dying frontal boundary pushes a line of storms through northern Texas. There is some question as to how far south these storms will get. It is possible that locations such as College Station and Huntsville could see some thunderstorms tonight. There is even a slight chance that locations further south, including The Woodlands, could see some of this action. However, I think a capping inversion will probably prevent such activity for most of the Houston metro area, including at least the southern half of Montgomery County.

Other than this, we should be rain-free through the weekend.

Thursday

Expect partly sunny skies and a high of about 90 degrees with plenty of humidity. Another warm night.

Friday

As skies turn mostly sunny, expect highs to nudge up into the low 90s with plenty of humidity.

Saturday, Sunday, and Monday

The holiday weekend looks hot and sultry. Highs will rise from the low 90s on Saturday to the mid- to upper-90s by Memorial Day with mostly sunny skies. Folks, it’s going to be Houston hot this weekend, so take all appropriate heat precautions. That includes sunscreen during the daytime with the Sun reaching an angle of 80 degrees during the early afternoon hours.

Wet Bulb Globe Temperature forecasts give a sense of the heat to expect this weekend. (Weather Bell)

Next week

So what happens after Memorial Day? It still looks like some sort of weak front arrives on Monday night or Tuesday. It’s late May, so your expectations should be for slightly cooler weather, and slightly drier air, and not much more. Still, beggars cannot be choosers at this time of year. Rain chances look a little bit improved later next week, but we’ll have to see about that. I don’t have much confidence in such a prediction.

Last week’s storms

Check back later this morning as Matt has a post on last week’s storms, and where they share some commonality with Houston’s history of similar events. It’s a great article with a lot of historical context.

Summer is here: Let’s talk heat forecasting

In brief: Today’s post talks about the arrival of summer-like weather in Houston, and breaks down the four phases of summer. We also discuss a new offering from the National Weather Service called “HeatRisk.” Finally, we look ahead to a hot and sunny Memorial Day Weekend.

We’re starting to see 90-degree days on the regular which, in my mind, signals the start of summer in Houston. Long-time readers will know that I like to break summer down into four phases. Why? Because “summer” season lasts so long, nearly five months. This is contrast to meteorological summer, which runs from June through August, and “solstice” summer, which runs from June 20 through September 22 this year. For me, Houston’s summer typically runs from about mid-May through mid-October. Here are the four phases:

  • Early summer: When we first start to see 90-degree temperatures with regularity, but some nights in the 60s are still possible, and there’s still the thinnest hope of a weak front
  • Mid summer: When highs run from 90 to 95 degrees, and nights are sultry, but you know it could still get worse
  • High summer: Somewhere between late July and early September there’s a period where temperatures reach the upper 90s to mid-100s and you realize, “Ok, this really is the worst.”
  • Late summer: This is the period in September and early October when days grow shorter and we usually see the first front or two of the season. But most of the time it’s still hot.

Early summer began this week in Houston, and we have a chance to bump into Mid summer early next week before we drop back into early summer. You may think it’s crazy to have gradations of heat during summer, as Houston is invariably hot and humid during the summer months. But as we found out last year, there is heat and there is heat. Last summer we used the “wet bulb globe temperature”to measure how hot it really felt outside, and we’ll continue to use this tool. However there’s now another way to assess the heat.

HeatRisk map for Monday, Memorial Day. (National Weather Service)

This year the National Weather Service is introducing a “HeatRisk” color-based scale that takes into account the following factors to provide guidance for outdoor activities:

  • How unusual the heat is for the time of the year
  • The duration of the heat, including both daytime and nighttime temperatures
  • If those temperatures pose an elevated risk of heat-related impacts

The scale ranges from green (little or no risk) to magenta (extreme). If we look at the risk for Memorial Day we can already see a few areas of Houston reaching an ‘extreme’ level of risk. This is due to temperatures likely in the mid- to upper-90s and the time of year, late May, as we’ve not re-accustomed ourselves to the heat yet.

In any case, feel free to use this planning tool as we go through the summer.

Tuesday

We’ll see a few more clouds today than we saw on Monday, and this should help hold temperatures to about 90 degrees. Winds will be from the south, at 10 mph or so, with gusts up to 20 mph. Aside from that it’s going to be another humid day, with a warm night in the mid- to upper-70s.

Wednesday

Skies should be partly to mostly cloudy on Wednesday, and this should allow some parts of Houston to stay in the upper 80s. However, if we get a bit of sunshine during the afternoon hours, highs in the low 90s are possible. Still warm. Still humid.

Thursday and Friday

These days will probably bring mostly sunny skies, so temperatures from 90 to the low 90s are likely. Nights remain warm.

Wet Bulb Globe Temperatures will be high this week, but not extreme. (Weather Bell)

Saturday, Sunday, and Monday

Hot and mostly sunny. Highs this weekend are likely to reach the mid-90s, with upper-90s possible on Memorial Day. By Monday it looks like a weak front will approach the area, bringing a chance of rain with it. However I don’t believe this front will arrive in time to modify conditions during the daytime on Monday.

Next week

The front should arrive on Monday night or Tuesday, and at this point it does appear as though the boundary will indeed push all the way to the coast. Don’t expect miracles in late May, but we might see some slightly drier air and highs in the upper 80s, with modestly cooler nights. It isn’t much, but it’s the best we can reasonably hope for at least the next three months, and probably longer.

Answering a few questions about last week’s superstorm, and assessing how hot it will get this week

In brief: Houston will remain warm and humid through next weekend, with partly to mostly sunny days and highs generally in the low 90s. Rain chances are low throughout the period. Today’s post also addresses some lingering questions from last week’s storms, including why the event was not particularly well predicted.

Over the weekend, the greater Houston region continued to recover from damaging winds last Thursday. On Sunday evening, CenterPoint said that it had restored electricity to more than 700,000 people who lost power, with about 240,000 customers still without. The transmission company said it remains on track to be “substantially complete” with power restoration by Wednesday evening. Before jumping into the forecast here are some additional thoughts about the very strong storms that arrived last week.

Outside of north Texas, it won’t rain much this week. This will help recovery activities from last week’s storms proceed. (Weather Bell)

Why wasn’t this well predicted?

This is a great question. The answer is that we have seen these kinds of setups before in which there is an atmosphere primed with moisture and instability, and with a potential trigger for supercell storms to form many times before. However, even hours before their development just west of Houston on Thursday, there was no ready data to indicate the true severity of the blow-the-doors-off storm that was coming.

It’s the kind of thing where there maybe is a 1-in-50 or a 1-in-100 chance that something so severe, a supercell event with very strong straight-line winds directly over the city’s urban core, could develop. If we had messaged that an “extremely dangerous and destructive event” was coming the previous 10 times there was such an atmospheric setup, and nothing of any real significance happened, who would believe us on the 11th time? There is a boy-who-cried-wolf problem here. The only real solution here is that we try harder to find that bit of data that gives us more confidence in a rare event like this one. I’m confident that Thursday’s storms will be studied in depth to identify such clues.

I was lying in bed on Sunday morning thinking about all of this—yes, I lose sleep worrying about this kind of stuff—and of all things a 2002 Houston Texans football game popped into mind. It was December 8, the team’s first season, and being an expansion franchise the Texans were not great. That week the Texans had to go to Pittsburgh and play the Steelers in near-freezing temperatures for a meaningless game. The Steelers were a decent football team, nothing fantastic, but were expected to blow the Texans out. The line was Steelers -14. The Steelers outgained the Texans 442 yards to 47. They won the time of possession with 40 minutes to 20 minutes. Texans quarterback David Carr was 3-of-10 passing, for 33 yards. That was in line with expectations.

But the Texans won 24 to 6. They returned three turnovers for touchdowns, and kicked a field goal after a short drive. The Steelers had many more penalties. Their two long drives ended in field goals rather than touchdowns. It was just an odd day. While the final score was within the bound of possibilities, on any given Sunday anything can happen when two teams meet, it was the lowest probability event. That’s kind of like what happened Thursday. A super-storm was within the realms of possibility, but was like an expansion team playing terribly, but still blowing out the Pittsburgh Steelers on the road in very cold conditions.

Why weren’t there more real-time warnings?

This is something Matt and I are taking away from the storms. I feel like we do a good job of forecasting the weather here, but where we struggle is in real-time coverage. Some readers have asked why we did not send out warnings for tornadoes on Thursday. That is because this is the express function of the National Weather Service, which has a large staff and the technology to send out real time warnings for tornadoes and other life-threatening weather events. Here’s more information about the agency’s wireless emergency alerts program. They are the experts at that, and we defer to them.

Matt and I were both tracking Thursday’s storm in real time. We were on top of things. And there was perhaps a 30 to 60-minute window between 5:30 and 6:30 p.m. when we could have provided some actionable information. However, in the time it would take to write and disseminate a post about that in real-time, the dynamic event might have already passed for most people. One possible solution is that we are likely to start sending (albeit very rarely) “urgent notifications” through our app. It is available for free here for Apple ioS, and here for Android. Regardless, we recognize this as a weakness and will address it here at Space City Weather. For one thing, we are changing the frequency of updates on days when severe weather is possible.

Monday

Our overall warm, but not extremely hot pattern will continue as we inch toward the end of May. With high pressure largely in control we’ll see this pattern largely persist through the holiday weekend, with the only really noticeable change in the strength of southerly winds, or a few more clouds on some days. For today, we’ll see highs generally in the low 90s, with only coastal areas unlikely to reach 90 degrees. Skies will be mostly sunny. Winds will blow from the southeast at 5 to 10 mph. Overnight lows will be warmer than we’ve seen, dropping only into the upper 70s.

Our weather will be nothing if not consistent this week. (Weather Bell)

Tuesday and Wednesday

In response to low pressure over the central United States, we’ll see an uptick in southerly winds with gusts up to 25 mph. Both days will see partly to sunny skies, with highs around 90 degrees. Nights remain quite warm.

Thursday and Friday

These will be partly to mostly sunny days, with winds perhaps slackening a bit. Highs in the low 90s. There is perhaps a 10 percent chance of rain showers each afternoon.

Saturday, Sunday, and Monday

Memorial Day weekend looks warm and sunny. Expect highs in the low 90s, with warm nights. Rain chances remain near nil. Plan your outdoor activities with confidence.

Next week

There are some hints of a pattern change by Tuesday or Wednesday of next week, with possibly a weak front sneaking into the area at the end of the month, and bringing with it a smattering of rain chances. This is far enough into the forecast, however, that my overall confidence is quite low. We shall see.