Matt Lanza

Houston summers are notably hot and humid. Many of us hate it, but it’s almost a badge of honor of sorts for us, right? Anyway, Hobby hit 100° yesterday and Bush hit 99° as well. For Hobby, that’s the third earliest date since 1930 that we’ve hit the century mark for the first time in a year, just being beat out by May 31, 1998 (100) and June 5, 2011 (102). At Bush Airport and officially for Houston, we tied for our eighth earliest first 99° reading. May 29, 1996 and June 2, 2011 top that list. The average for our first 99° at Bush is July 16th, and the average for our first 100° at Hobby is July 17th. This is very early for this kind of heat. Granted, we’re going to be dealing with a borderline historic ridge of high pressure in the West the next several days, so I guess it should not be much of a surprise, but after a very wet May, color me a bit surprised we went this far this fast. Hopefully not a harbinger of things to come this summer.

So the obvious question is: Will the heat last? Let’s try to answer that.

Today

While we expect today will be another scorcher of a day, we may end up a degree or so cooler than yesterday, and we may also see a couple more showers than we did yesterday too. Maybe. Most folks will still probably stay dry today though.

Upper air temperatures look stoutly warm this morning, but by evening they’re running a tick or two under Sunday. So, in general, expect mid to upper-90s today. Heat index values will get up over 105° in spots this afternoon, so please exercise caution if outside. In addition, today will be another ozone action day for the area, so take care if you have respiratory sensitivity.

Tuesday & Wednesday

Tomorrow we see a small bite taken out of the heat, so we’ll probably drop off another degree or two compared to Monday. We’ll call it mid-90s. Better rain chances look to arrive Tuesday, as a slightly larger scale disturbance in the upper atmosphere moves across the region. On Wednesday, we’ll see a good setup for at least scattered showers and storms. Look for mid-90s once more. Morning lows will be in the 70s to as warm as 80° perhaps.

If I were classifying rain chances, yesterday was about 5 to 10 percent coverage. Monday will be 10 to 20 percent, and Tuesday/Wednesday would be 30 percent coverage. So, many folks may not see any rain at all, but at least some of us should. Hopefully.

Thursday

On Thursday we stay flat or lose another degree or so in temperature, as we lie between high pressure dominating the West and a trough on the East Coast. Already low overall rain chances may lower a bit more on Thursday. Look for mid-90s by day and 70s to near 80° by night/morning.

Beyond Thursday (Tropics)

Looking out to Friday and beyond, our attention turns to Invest 92L, which I went in depth on yesterday. Honestly, not much has changed since that post. The system is still messy looking. It will still have high shear to deal with, and there will likely be some dry air over Texas that will attempt to fight it back a little bit. So there likely remains a fairly low ceiling on just how intense this system can become.

As Invest 92L comes north in a very sheared environment, it will likely continue to have the bulk of its moisture kicked off to our east. Again, if you look at a GFS model forecast of relative humidity in the upper atmosphere, generally a decent indicator of how constructive or destructive the environment will be surrounding a tropical system, there is a clear signal for very, very dry air over Texas. This likely means a.) a sharp cutoff to how far west precipitation can expand on the west side of the storm and b.) the risk that some of this dry air gets “entrained,” or wrapped into the system itself as it comes north, limiting how well-organized it can become.

So what does this mean for the Houston area from Friday into the weekend? While I’m certainly sounding very unexcited about rain from Invest 92L in the Houston area, it will boost our rainfall odds a bit from where they are on Thursday. So look for at least isolated to scattered showers or storms on Friday, Saturday, and Sunday as 92L draws north. Uncertainty increases a bit obviously as we march through this weekend, but in general, we continue to feel the heaviest rain will stay to our east, possibly well to our east. But I would expect at least some chance for scattered rain over the weekend. We’ll fine tune this through the week.

Temperatures, especially if rain stays well off to the east of Houston will likely be warm to quite hot heading into the weekend, maybe cooling a bit as rain chances increase.

With respect to your plans for the week or weekend and Invest 92L? I would not make any changes because of this system right now, but I would check back each day for an update to make sure nothing has significantly changed. More tomorrow.

Good Sunday morning to you. As promised, we are here with an update on the tropics, as we watch the potential for development in the Gulf this week.

Quick Houston weather update

I just want to lead with a quick update on our near-term weather here in Houston. It hit 98° yesterday officially, and we’re running slightly hotter already today. We typically don’t see our first 98° day until July 9th, so we’re running close to a month ahead of schedule there. That doesn’t mean we’re necessarily headed for 100° this afternoon, but it’s going to be another scorcher. Please take it easy outdoors. In addition, it’s an ozone action day, so anyone with respiratory sensitivity will want to limit outdoor activity.

The big difference between today and prior days is with rain chances. Yesterday was close to zero. Today will be slightly above zero. So we feel at least a few locations, possibly parts of the city, will see a cooling downpour this afternoon. Outside of that, it’s just going to be red hot. Tomorrow and Tuesday will likely see a few more scattered showers and storms in the afternoon. Prior to those developing, look for sun, clouds, and temperatures into at least the mid-90s, with morning lows in the 70s to near 80° in spots.

Tropical update

Alright, the main point of today’s post is to discuss the tropics.

One sentence summary: A tropical system seems likely to form in the Bay of Campeche over the next 5 days, and while we will watch it closely, we are currently expecting a fairly disorganized system with a decent chance that the majority of impacts remain shunted off to our east.

In meteorological speak, when we have a specific disturbance we want to get more information on before it gets close to becoming a tropical depression, it is labeled an “Invest,” or area to investigate. In the Atlantic basin, invests are labeled 90L to 99L, and then the list recycles. In the southern Gulf, we now have Invest 92L.

From the satellite image above, you can see a blotchy area of thunderstorms and little organization. This is mostly what we expected to see this weekend. Development from 92L is probably going to be slow. In fact, the National Hurricane Center says the chances of a depression forming seem to be most likely later this week, so we’ve got some time to watch. As of now, they are assigning 50 percent odds of development over the next 5 days.

In addition, this system is likely to fester and sit over the southern Gulf the next few days without moving much. So that means any impacts here in Texas from 92L likely would not occur until very late this week or next weekend. You might ask why it’s going to struggle to develop if it’s sitting over the southern Gulf, which is about 2 to 3 degrees warmer than normal. Well, for one, it’s sitting over 25 kts. of wind shear, with an area of 40 kts. of wind shear to the north. That’s prohibitive to development.

This shear is not expected to relax much over the next few days. In fact, this wind shear may linger in place through Wednesday or Thursday or beyond.

Given a lack of serious steering currents right now, the system is expected to stay in place over the Bay of Campeche. But, as the week progresses, a strengthening ridge in the Western US, a strengthening trough along the East Coast of the U.S., and a building ridge in the western Caribbean will act to gradually invite 92L to drift northward. The exact track of this system will depend on the actual strength of these features and exactly where the center of Invest 92L forms. In general, modeling is telling us to probably expect a northward drift later this week, with some acceleration to the Gulf Coast on Friday or Saturday. From there, it seems possible that the forward speed may slow. But details on that aspect of things are difficult to really pin down right now. Models seem to favor a track of the center toward areas just east of Houston, keeping most of the Houston area on the less impactful side of the system, but again, it’s too early to be too confident in any track specifics.

In terms of intensity, I think two things are going to seriously inhibit how strong Invest 92L can ultimately get. The first is shear, as noted above. I don’t see any evidence on models that this is going to relax much. That’s the first hurdle this system will have to overcome. It may also further help us in that wind shear could allow for much of the more significant system impacts from rainfall to pushed even farther to our east. For those of you reading us from places other than Houston, it’s important to realize that these early season systems are rarely ever symmetrically put together and impacts from heavy rain in particular can extend hundreds of miles to the east of the center.

The other thing that might lower 92L’s ceiling for intensity would be dry air coming off Texas.

If you look above, you are seeing the GFS forecast of atmospheric relative humidity several thousand feet above us for next weekend. The brown over Texas indicates dry air. The red “L” is the approximate center of 92L as forecast by the GFS on Sunday morning. Don’t focus too closely on that. The green color indicates more ample atmospheric moisture. What is this telling us? Even if the track of 92L shifts 150 miles in either direction, it’s still going to be dealing with dry air possibly getting wrapped in from Texas. That should limit the ceiling of intensity as the storm comes north. Moisture from the storm may be displaced a good bit east of the center as well.

The bottom line, as is often the case with these early season storms: While we will continue to watch closely, at this point we don’t see this as a serious wind-making risk for the area. We are viewing this as a rainfall risk, as well as for some coastal impacts (minor to moderate tidal flooding, overwash, rough seas, etc.). Sitting here on Sunday, I don’t think we need to be especially worried about this either way, but I do feel we should watch things closely this week, just in case anything changes, particularly with respect to rainfall. It’s probably not a bad idea to check in on the forecast once per day and make sure we’re still status quo on things. But truthfully, I feel mostly at ease with where things stand today. Sure, that could change, but for now, we’ll take it!

Look for the latest in our usual Monday morning update tomorrow. Meanwhile, stay cool!

This week has been a good week to dry out a bit. And we have needed that badly. Today should be our fourth or fifth straight mostly dry day, something we haven’t been able to string together since basically early May. As we go through the weekend, most of us will remain dry, but those typical summer rain chances will creep back into the forecast slowly.

Today & Saturday

The next two days will be partly to mostly sunny and hot as high pressure remains locked in control. Look for highs in the low to mid-90s and lows in the 70s. It will feel like 100° to 105° at times when you factor in the humidity, and a handful of spots could feel even a bit hotter.

We like to say that we’re used to heat here in Houston, but these first days of heat index values this hot can always tax you just a bit more than usual. Try to take it easy outdoors, drink plenty of water, and check on any elderly or vulnerable family, friends, and neighbors.

Sunday through Tuesday

While rain chances look to be nil through Saturday, we have to mention the chance on Sunday afternoon. As high pressure begins revving up in the Western U.S. (Phoenix expected to hit 115° or hotter next week), a boundary off to our north and east will slide back toward southwest Louisiana and East Texas. With our area sort of on the periphery of this high pressure, we could see the Gulf open back up a bit next week and the chance of showers and storms re-enter the picture. The GFS model forecast of the upper pattern on Monday evening is shown below.

Rain chances will be highest north and east of Houston on Sunday and then anywhere in the area on Monday or Tuesday. Widespread heavy rain isn’t expected, but isolated downpours could be locally heavy. Some areas will see nothing, while others could see an inch or two. Outside of the rain chances, it will be hot and humid with highs again in the 90s and lows in the 70s. Those nighttimes may feel just a little extra uncomfortable next week.

Late next week & tropics

The forecast heading into late next week will begin to see confidence drop off, as we introduce the potential for a tropical disturbance in the western Gulf of Mexico. I would expect to see the National Hurricane Center begin to include this area on their 5-day tropical outlook over the weekend. Modeling implies at least a 50 percent chance we get some kind of tropical low (call it an “invest” or depression-level type system), with about a 20 percent chance of a tropical storm and minimal chance of a hurricane.

Nothing eye-popping here, but certainly some continued, if not growing support for a tropical system of some sort. Timing-wise, whatever does happen would probably approach Texas through Louisiana on Friday or Saturday of next week.

It may feel too soon to talk about a legitimate tropical system in the Gulf, but it is coming up on mid-June, and hurricane season is definitely underway. While there is certainly the potential for impacts, at this stage in the game, I don’t see anything overly alarming about this system. As always, that could change, but for now this is something to be aware of, not worried about. Check back in with us this weekend, as I will have a more detailed post on everything we know about this specific system tomorrow or Sunday.

In the meantime, the expectation for later next week should be continued minor to moderate rain chances Wednesday, gradually escalating as we get toward the weekend. We could have marine and wind impacts if a tropical system does indeed develop, but it’s far too soon to say anything specific about that.

Again, look for more about this system, probably Sunday morning. Meanwhile, keep cool!

Good morning. It was quite a wet afternoon and evening on Thursday, though outside of a few areas of localized flooding, the rain didn’t cause too much heartburn. Except in Deer Park, where it looks like a microburst (strong, straight-line winds) inflicted some damage in the area around the high school.

Last flag standing! There were three flags flying before the storms hit Deer Park today, but only one withstood the whipping winds, the TEXAS flag! Deer Park PD released this video! #khou11

More on the damage in Deer Park: https://t.co/W2VhqGgx8r pic.twitter.com/8oPorUIiTD

— KHOU 11 News Houston (@KHOU) June 4, 2021

Divergent signature on THOU radar indicative of a possible wet microburst that caused damage at Deer Park High School North Campus earlier this afternoon. VIL values also sharply fell around this time. #houwx #txwx https://t.co/pSZdtTzWJu pic.twitter.com/rzTsfjn54A

— Ian Gunter (@ianswx) June 4, 2021

With continued chances at rain, we will continue to carry our Stage 1 Flood Alert into at least Saturday.

Before we jump into the forecast details, in case you missed it, Space City Weather now as an app available for both Android and Apple users! You can check out Dwight Silverman’s introductory post for more details. And please, if you notice any bugs or issues, shoot us an email at [email protected]. We’ve gotten lots of feedback so far, and we will do our best to address your reports in a timely manner! I just want to personally thank Dwight, Eric, and especially Hussain Abbasi for getting us here. It’s just a really good, clean, functional app, and I’m thrilled we can share it with you all.

Alright, let’s get into this somewhat tricky forecast.

Today

Radar this morning shows that most heavy rain has pushed offshore south and east of Houston. There are some scattered showers, including a few downpours in spots west of Houston.

Storms should get going again along the sea breeze this afternoon, as it pushes inland from the Gulf. There’s a certain degree of randomness to these things. Yesterday’s rain began on the sea breeze and then transitioned to a widespread steady but lighter rain as a disturbance coming out of central Texas intercepted the sea breeze boundary. Today may be more hit and miss, but risk for areas of heavy rain will continue. Atmospheric moisture remains fully loaded, but instability, which we need to really get things popping, looks to be down a bit today. Expect at least some rain and some pockets of heavier rain, but at this time, we don’t expect widespread heavy rain today. We will let you know if that expectation changes.

Tonight through Sunday

We supposedly enter the heart of this rainy period tonight and tomorrow as the upper low ejecting out of Central Texas meanders north and east past our area. As this happens, we may, for a time, maximize the ingredients necessary for periods of rain and storms, and this is where we will watch for more widespread heavy rainfall chances and more notable street flooding potentially. I say “supposedly,” because there’s been a shift in modeling today, which favors areas east of the Houston area, mostly in Louisiana for the heaviest rain risk. Upper lows are notoriously tough to forecast and little changes like this can lead to big expectation changes. We will keep you posted through the weekend.

So between tonight and Sunday, don’t expect it to rain the entire time, but there will be periods of showers, storms, and locally heavy rainfall. We think Saturday may have the highest chances for that to happen, with perhaps the worst of the action shifting out of our area by as early as Saturday afternoon and staying east of us Sunday. That doesn’t mean a dry weekend, but it does perhaps allow for more frequent breaks in the rain. Most outdoor plans this weekend will likely need to be either a true game time decision or postponed if you would rather not deal with the hassle.

Taking the glass half full approach (depending on your point of view, of course): We typically start to ramp up into summer heat around now, but there is absolutely no heat to be found thanks to the clouds and rain. Highs this weekend will generally be in the low-80s with lows in the 70s.

How much more rain? Between now and Sunday evening, we expect that most areas will see another inch or two on average.

Some places will almost certainly see more, while some other locales may see a bit less. Again, the Stage 1 Flood alert we have posted is meant to cover for those handful of locations that see mostly nuisance street flooding like we saw yesterday.

Next week

I fully expect more rounds of showers and thunderstorms to start next week. Monday and Tuesday look like they will have the highest odds of wet weather. But I don’t see a truly dry day area-wide before next Wednesday at the earliest.