Heat advisories begin as temperatures climb toward triple digits in the Houston region

Just what is happening around here? I take off a few days for a family reunion in a cooler climate, and return to sultry, face-melting summer heat and a forecast that includes 100-degree temperatures. I absolutely blame Matt for this and let me tell you, I’ll be writing a stern letter to the managing editor.

Alas, it’s only going to get hotter. And there remains no real confidence in when an end-date might be in sight. It high pressure domes for as far as the eye can see.

Please take care outside today. (National Weather Service)

Wednesday

Temperatures remained confined to the mid-90s on Monday and Tuesday in most of Houston, but today we’re going to begin taking another step up. The central and western parts of the metro area will see highs in the mid- to upper-90s, and combined with the high humidity, this will bring dangerous heat to the area. The National Weather Service has issued a heat advisory for the time period from 1 pm to 7 pm CT today for all but the eastern part of our region. Winds will generally be light, at 5 to 10 mph, with slightly higher gusts. Lows tonight will only drop to around 80 degrees.

Thursday

Temperatures will pretty much be in the upper 90s to 100 degrees for the entire area, with the exception of the immediate coast. And if you’ve lived in Houston for more than 10 minutes, you probably don’t need to ask about the humidity.

Friday through Tuesday

We’re highly confident that these will be sunny and hot days, with most of the area reaching triple digits. This extreme heat will be driven by a high pressure system that will lead to sinking air, clear skies, and ideal conditions for daytime heating. Please take precautions with outdoor activities during the afternoon and early evening hours. Rain chances look to be 10 percent, or lower, each day.

Congratulations, everyone. (Weather Bell)

Next Wednesday and beyond

The truth is, there is no concrete sign that high pressure will abate during the second half of next week, so the most likely forecast is one of continued high heat and very low rain chances. Maybe some slight relief will arrive as we get toward next weekend. We’ll see.

Heat will continue to build through the week in Houston

On Monday, Houston topped off around 95°, after a 94° on Sunday and 93° on Saturday. So far at least, our temperatures seem to be underachieving a bit. That may be a bit of cloud cover or the relatively wet weather we had through late spring acting against heat. Regardless, it will remain plenty hot through the week.

Today

Today’s upper air temperatures are expected to be about 1 to 2°C warmer than they were yesterday, which should translate to a bump of a couple degrees to our high temperatures. Look for mid to perhaps some upper-90s in most inland spots, slightly cooler at the coast. Storms are expected to remain well north of the area today, but some clouds from those storms could filter into some of the region.

Heat advisories are now posted southwest of Fort Bend County and could be expanded depending on how things evolve today. (NWS Houston)

Peak heat index values (or feels like temperatures, if you prefer) will be in the 103 to 107° range in Houston, just shy of heat index criteria in most of the area. But to the west, they are expected to flirt with 108°+, requiring a heat advisory. This could be expanded later today and certainly will be as the week goes on.

Wednesday

Morning lows will be in the upper-70s tomorrow. We tack on another 1-2 degrees on Wednesday in the upper atmosphere, so look for mostly upper-90s for highs here. As seems to be the case, some passing storms well off to our north may send some “debris” clouds this way which may keep the risk skewed slightly lower for high temps. We’ll see.

Heat index values should ratchet up a little bit tomorrow as temperatures increase a bit too. (Pivotal Weather)

Heat index values will nudge up some tomorrow, with peak readings perhaps more into the 105 to 110° range, which could yield wider coverage of the heat advisory.

Thursday through Sunday

No changes to the forecast here with minimal rain chances (model probabilities are under 15 percent all days) and a mix of sun and clouds each day. High temperatures will likely be in the upper-90s most days with at least a chance at 100+ officially. But admittedly, after yesterday I am not as convinced we do that. But, whether it’s 100+ or not, we will likely see heat index values average in the 105 to 110° range on all days, meaning we will potentially put together a string of heat advisory days, so make sure you’re keeping cool and drinking plenty of water.

We still cannot confidently answer when this heat will start to relax. Maybe later next week.

Tropics

We continue to update the tropics daily over at The Eyewall, and we have little to discuss right now! Good news for sure, and with this dry, hot air mass dominating Texas and the western Gulf, we’re very much in the clear for the next 7 to 10 days. Look for a larger feature at The Eyewall tomorrow that goes in depth on what has been happening in the Gulf of Mexico in recent years.

Space City Weather’s guide to the first heat wave of 2023

After a couple rounds of some gnarly storms on Thursday and Saturday, the region should be in for a fairly durable break over the next several days. However, the cost will be the strongest heat since last summer. It makes for a fairly simple weather forecast, but there are at least a couple things to note. Since every day looks to be about the same, we’ll discuss things a little differently today.

How hot are we talking?

Forecast highs today through the weekend look to be in the upper-90s to low-100s each and every day. There is probably a slightly higher chance of 100+ as we get closer to the weekend as the upper level ridge of high pressure that’s causing this heat flexes a bit more.

The NWS forecast as of Monday morning through the weekend shows escalating heat this week, with the hottest coming Friday and Saturday. (Weather Bell)

Models indicate about a 70 percent chance of hitting 100° during the peak of the heat (expected Friday through Sunday), with about a 35 percent chance of hitting 103° and a 15 percent chance of 105° in Houston. We get hot in summer here in Houston, but this is sort of the next level of heat. Morning lows will be in the 70s to near 80 each day.

How bad will the humidity be?

The humidity will be about as bad as you typically see in Houston in summer. There’s nothing about this air mass that’s overly impressive in terms of humidity right now. Dewpoints will be running near to maybe just a little above average. So, you’ll feel the humidity for sure, but that’s typical for our area. However, with abnormally hot weather to go with that humidity, it sets us up for escalating heat this week.

As of right now, the National Weather Service does not intend to issue heat advisories for the Houston area today or tomorrow, but that will probably change later this week when we start testing that criteria (heat index, or “feels like” values of 108+ or air temperatures of 103+) a little more. Excessive heat warning criteria features heat index values of 113° or higher or air temperatures of 105° and up.

The forecast for heat index values on Thursday afternoon shows 110° for a “feels like” temperatures in Houston, which would easily place us in heat advisory criteria. (Pivotal Weather)

Initially, expect afternoon heat index values of 103 to 107°, worst in and south and east of Houston, escalating to near 110° or hotter by late week. Whatever criteria we do or do not hit, it will be important to take it easier than normal in the afternoon heat. The NWS Houston office has a handy web page with graphics and information on heat safety. Look before you lock, drink water, wear sunscreen, and try to stay cool.

Will anything make this more tolerable?

If you’ve been paying close attention since May, you may have noticed a real lack of wind around these parts. We had some pretty windy months earlier in spring and also last spring. But since at least 2010, no May 1st through June 10th period has had a lower average wind speed in Houston. Relative to recent years, it’s been dead calm. That is finally changing this week.

The average hourly wind speed in Houston since May 1st has been the lowest for that period since at least 2010, with only May 1-June 10, 2012 coming close.

We expect wind this week to average about 10 to 15 mph or so, with occasional daytime gusts of 20 mph. While that won’t make it feel nice with temperatures this hot, it will take a bit of the edge off. It’s a bit counter-intuitive, as this sort of heat is typically associated with what we derisively call a “death ridge,” a hot, dry, calm atmosphere. But we’ll be downstream of it at least initially, so we benefit with some wind.

How about rain chances?

Those will be mostly absent. I would say that if you live north of Houston, up toward, say Huntsville or Madisonville, you have at least a chance at getting grazed by some storms that will pass across North Texas this evening, Tuesday morning, and Wednesday morning. Model guidance from the National Blend of Models (NBM) shows about a daily peak of 10 to 15 percent chances of measurable rain over the next 7 to 10 days for Houston, and maybe 15 to 20 percent up north of Huntsville and Walker County. Chances look absolutely paltry south of I-10 right now. So, no, it does not appear we will see much, if any rain over the next week.

Do we need to worry about power outages?

At this time, ERCOT says that there may be calls for conservation at some point, but they do not anticipate dealing with outages this week. I have seen that thought echoed by others “in the know” on social media that do not work for ERCOT or Texas. It’s always a good idea to conserve where you can this time of year, but the grid should be able to manage the heat for now.

When will this end?

I wish we could answer that with confidence.

If you look at a loop of the weather pattern 20,000 feet up (500 mb level) over the next 10 days, you see a lot of horseshoe-like curvature to the black lines over Texas, indicating high pressure is firmly in control through that period. (Pivotal Weather)

If you look at the weather pattern about 20,000 feet up over the next 10 days (looped above), you can see that the ridge flexes this weekend (indicated by a horseshoe-like curvature to the black lines over Texas) into early next week. We call this a “persistence forecast,” where every day is basically mostly like the previous day. What that means is we’ll likely be dealing with high temperatures of 97 to 103 degrees over the next 10 days. I will caution that there’s always a chance we can’t see a disturbance or something that can throw a wrench into a persistence forecast like this. But right now, I certainly don’t see what that catalyst would be. After midweek next week, it does appear that the ridge may retreat to the west some, which could allow for a bump in rain chances and cooler weather.

Stay cool, and we’ll be back with an update on Tuesday morning!

Most of Saturday looks fine before scattered strong evening storms mainly north of Houston

Houston hit 95 degrees yesterday, our hottest day so far this year, and we’ll be on track to come close to that again today. Over the last 30 years, the average first 95 degree day in Houston was on June 8th. So we’re right on schedule this year. And while heat remains the primary weather story for the next week or more, there will be some storms worth watching later today. But not for everyone.

Everything looks pretty okay through early afternoon. So if you’re looking to get in a morning swim or have a morning/midday birthday party to attend, no worries.

Things get more complicated this afternoon. Storms should begin to fire up in North Texas, near DFW, which is the primary area we’ll be watching this evening. Additional isolated storms are possible in the northern reaches of the Houston area, so if you’re on Lake Livingston or Lake Conroe this afternoon, just keep an ear out for thunder and seek shelter should you hear some. An additional very isolated shower like yesterday is possible in the Houston metro area. But for the most part, things look okay through, call it, 3 to 5 PM or so.

South of Houston is in in a level 1/5 (marginal) severe weather risk, while the rest of the metro area is in a level 2/5 (slight) risk. An enhanced risk (3/5) is in place for College Station, Huntsville, Madisonville, Crockett, and portions of Lake Livingston (NOAA SPC)

Thereafter, things become a bit trickier. Storms near Dallas should be hauling south and east during the late afternoon, finally reaching the northern fringe of southeast Texas by about 5 to 8 PM. Assuming they can hold together, they’ll get into Huntsville, Conroe, and Cleveland by about 8 to 11 PM. And from there, the northern half of the Houston metro and The Woodlands around Midnight, give or take. Everything will push offshore overnight.

What can we expect: North of Houston, where the enhanced risk is in place, which includes College Station and Huntsville, watch for strong, damaging winds from any storms, the potential for hail, and even an isolated tornado (though that would probably be a higher risk closer to Dallas). As the storms come south from there, the threat for wind and hail will continue — but slowly diminish. Any damaging winds would probably be more isolated than widespread. Hail would be isolated as well. And there’s a chance that some places, especially in the western third of the Houston area see nothing. By the time the storms get to the coast overnight, they may just have lightning and thunder.

A forecast radar of how storms could play out this evening. Notice that they look at their worst near Huntsville and then gradually weaken as they drop south and east. Exactly who sees storms may be different, but in general, this is how it should go. For the Houston metro area, these should not quite pack the punch of Thursday’s storms. (Pivotal Weather)

At this point, I don’t believe these storms will have the same impact on our area as Thursday’s storms did, and the highest odds for anything like that will be north of Highway 105 and east of I-45. That said, there’s at least reason to keep tabs on things this evening across the area, so stay aware of the weather around you. Conditions should improve overnight and tomorrow looks fine.

Sunday see our heat wave resume its upward trajectory, into the mid or even upper-90s in some spots. (Pivotal Weather)

Look for highs in the mid-90s, maybe into the upper-90s in a couple spots on Sunday. We’ll be back with more on Monday!