It isn’t normal to hit 100 degrees this early in summer in Houston

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.

Forecast high temperatures for Monday remain uncomfortably hot, with heat index values of 105°+ likely in spots this afternoon. (Weather Bell)

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.

Invest 92L remains in the Bay of Campeche, a sheared, disorganized mess this morning. (Tropical Tidbits)

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.

Very dry air over Texas will likely act to limit how far west the rainfall from 92L can come and how strong 92L can become. Even a track right into Houston would likely still see the heaviest rain off to our east. (Tropical Tidbits)

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.

Scorcher of a weekend continues for Houston as we watch the southern Gulf for very slow tropical development

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.

Another scorcher is expected Monday, with most locations away from the coast reaching or exceeding the mid-90s. (Weather Bell)

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.

The satellite view of Invest 92L shows a good deal of thunderstorm activity in the Bay of Campeche this morning, but no organization whatsoever. (Weathernerds.org)

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.

The National Hurricane Center says Invest 92L won’t move much the next few days but has about a 50% chance to develop into a depression by later this week. (NOAA)

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.

Wind shear is ripping in the vicinity of Invest 92L, which will likely inhibit development over the next few days.

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.

Dry air is going to be abundant over Texas this coming week, some of which may get entrained into Invest 92L, limiting how strong or well-organized it can become. (Tropical Tidbits)

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!

Rain chances slowly return to Houston’s forecast by later in the weekend

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.

On Saturday afternoon around 4 PM, it will feel like close to 105° over parts of the Houston metro area. Some places could feel even a bit hotter. (NWS via Weather Bell)

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 increase next week as a massive ridge of high pressure builds to our west, leaving the door at least cracked open for some Gulf moisture & possible passing disturbances. (Pivotal Weather)

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.

European ensemble probabilities for a tropical storm late next week remain fairly low, although support for one has increased slightly over the last couple days. (Weather Bell)

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!

Hot and sunny as Houston digs into proper summer weather

Good morning. I want to thank you for all your lovely remembrances about Tropical Storm Allison in the comments here, and on Facebook yesterday. For me, too, it is difficult to believe it was 20 years ago. And after the floods, those were the worst mosquitoes I have ever seen in Houston, and that’s saying something!

Houston’s forecast is pretty straightforward from now through most of the weekend. We’re going to experience a lot of sunshine, and our warmest weather of the year as temperatures stay in the mid-90s for much of the region away from the coast. Rain chances will remain near zero until later on Sunday, and most of the region probably will stay dry until the early or middle part of next week when the tropics may, or may not, intervene.

Thursday

The combination of high pressure expanding northward into the region, and a capped atmosphere, should prelude any shower activity today across Houston. Skies will see a mix of clouds and sunshine as highs push into the low- to mid-90s across the region with light southerly winds. Nighttime temperatures will probably drop into the upper 70s away from the coast.

Friday and Saturday

As high pressure expands across the region, these will be hot and sunny days, with highs in the mid-90s for almost everyone by the immediate coast. Lows will be warm, but at least not in the 80s for most, as can happen later in the summer.

Hello, 90s, for this week and next. (Weather Bell)

Sunday and Monday

High pressure may recede to the west, and this could open up shower chances for some areas on the eastern side of Houston. But any showers that develop will be short-lived, and frankly I expect most of the area will probably remain dry on these days, with mostly sunny skies and warm conditions in the mid-90s.

Next week

Some clouds will return later next week, and this should help to moderate temperatures slightly, and bring back a chance of sea breeze-driven showers during the afternoon hours. Whether these conditions persist for all of next week will depend on the evolution of a tropical system that may form in the southern Gulf of Mexico next week, as discussed below.

The tropics

If you were to only look at the operational runs of the European and GFS models this morning, you’d see a tropical depression of some sort forming in the Southern Gulf of Mexico late Thursday or early Friday of next week. Both of these models then bring a depression or tropical storm northward, toward Texas and Louisiana, about nine days from now. This would lead a keen observer to think that we may see some tropical weather, particularly in the form of higher rain chances, toward the end of next week. You might be concerned.

European ensemble model forecast for tropical storm formation from next Wednesday through Friday. (Weather Bell)

However, and I can’t stress this enough, the global models have been waffling all over in their solutions for this system. Moreover, there is not all that much support for a tropical storm forming in the ensembles, or moving that far north—it seems just as likely that if a depression forms it will remain bottled up in the Southern Gulf of Mexico. And finally, we’re talking about forecasting a system more than a week from now, when we would expect there to be large errors in the models. Given their inconsistency from run to run, we’re filing this under “Something to watch, but not really be concerned about at this time.” We will, of course, keep you updated as needed.