Houston’s weather for the next several days will be influenced by high pressure to our west, and a slightly drier atmosphere thanks to a more northerly flow. By this weekend our eyes will turn toward the Gulf of Mexico, and the potential for a tropical system to disrupt our weather. We still have a lot of questions about Invest 97L in terms of intensity and track, but it seems clear that this tropical wave will move into the Gulf of Mexico. More below.
Wednesday’s highs in Texas — it could be worse in August. (Pivotal Weather)
Wednesday
Conditions will be quite warm today as a northerly flow continues to bring slightly drier air into the region. Dry air warms faster, so we can probably expect highs to reach into the upper 90s for most of the metro area. Rain chances remain near zero with the abundance of dry air. Our evening and overnight weather should again feel slightly drier, although the effect will be more pronounced for inland areas. For August, we can’t complain.
Thursday and Friday
The pattern remains more or less the same for the rest of the work week, although we anticipate winds turning from the north to the east on Thursday, and this will slowly modify our air mass to become a bit more moist. Look for highs in the mid- to upper-90s, which should not be too extreme. Lows should fall into the mid-70s, which is tolerably pleasant for the depths of August. A few stray showers may develop near the coast on these days, but we don’t anticipate any organized rainfall.
As we’ve been telling you for essentially weeks now, the tropics are becoming very active. Some of this is just basic math—as we approach late August and September, the tropics usually come alive. But there is more at play this year, with things happening in the background that should allow for basically an “outbreak” of sorts of tropical systems across the Atlantic basin in the days ahead.
Tropical outlook in a sentence
There will be at least two legitimate opportunities for tropical systems to develop and potentially impact some part of the Gulf of Mexico over the next 10 days, and an additional system or two may develop farther out in the Atlantic as well.
Invest 97L: First in line
The system the models are most bullish on is Invest 98L, which we’ll discuss below. But the one we are most concerned with more immediately is Invest 97L, because this is closer to us, and it is the type of system that can sneak up on us and cause some problems.
The National Hurricane Center says Invest 97L has a 70% chance of development in 5 days, while Invest 98L behind it has a 90% chance of development (NOAA)
Invest 97L is currently over the eastern Caribbean Sea. It’s not terribly well organized, and you can see a satellite loop from Tuesday afternoon showing mostly just a “blob” of storms at this point.
Invest 97L is on the right-hand side of this loop and is the “blob” of storms in the Caribbean Sea. (Weathernerds.org)
Over the next few days, 97L will plod along in the Caribbean, interacting at times with a disturbance over South America. So development is only expected to be slow or gradual. Eventually, it will end up in the western Caribbean, somewhere near the coast of Honduras or the Yucatan. I can hear 75% of our audience now saying, “Wait, that’s how Harvey happened, right?” And the answer is, “Sort of, yes.” It’s the elephant in the room here, obviously, so let’s discuss and compare real quick.
By the time the disturbance gets into the Western Caribbean this weekend, the upper air pattern will be favorable for it to gradually lift north. Here’s a map from the GFS ensemble valid on Saturday afternoon. We’re looking at the 500 mb level, or about 20,000 feet up, basically the large-scale steering pattern for this time.
Saturday afternoon’s forecast upper level pattern off the GFS Ensemble mean shows a couple key players in Invest 97L’s ultimate outcome.(Tropical Tidbits)
On Saturday afternoon, 97L should be off the Yucatan or Belize or just north of Honduras. It will be steered to the west by high pressure near Bermuda, while at the same time, a trough of low pressure in the upper atmosphere over the Lower Mississippi Valley is going to try and “pull” Invest 97L to the north. So at this point, the system should be moving to the northwest.
So in that respect, a middling system that gets pulled north and west across the Yucatan and into the Gulf of Mexico, Invest 97L is similar to Harvey. But I’m going to intentionally stop with the similarities there because the potential of what this does is much different from Harvey.
There is a chance that the trough remains strong enough to continue in its effort to “capture” Invest 97L, allowing it to come north into the Gulf and toward Louisiana or perhaps the Upper Texas Coast. That scenario can’t be ruled out. There is also a chance that Invest 97L gets “missed” by the trough and ends up stationary without much to steer it over the Gulf of Mexico. While that’s not a huge rainmaker on land, that becomes problematic because there would be a chance Invest 97L could strengthen while sitting offshore. Another possibility is that the Bermuda high continues to expand so much so that it just pushes 97L into Mexico as a weak rainmaker. Harvey was a once in a lifetime storm in terms of rainfall, so we don’t want folks to worry about a “Harvey” type storm right now. There are indeed some similarities in the initial overall big picture, yes. But that’s where it ends right now. What we should be doing (and what Eric and myself will be doing) is making sure we are prepared to take action late this weekend or early next week just in case it becomes clear that 97L will become a problem for us. We will keep you posted.
Good morning. A front is having subtle effects on Houston’s weather, but we’re still going to be plenty hot in the coming days. High temperatures should moderate slightly by the weekend, but we’re still looking at mostly sunny weather for several days. Next week our weather will be guided, to some extent at least, by any tropical systems that move into the Gulf of Mexico. We’re not seeing any direct threats, at least not yet, and Matt will have a full rundown later today on the tropical state of play.
Low temperatures on Wednesday morning will be slightly cooler than we’ve been seeing for most of August. (Pivotal Weather)
Tuesday
Expect hot and sunny conditions to prevail, with highs pushing into the upper 90s to 100 degrees this afternoon as drier air helps with warming. Despite the drier air, models are picking up a slug of moisture in the lower atmosphere that may help to generate some scattered showers primarily on the western half of the metro area later today. This should be pushed away by this evening as additional dry air continues to move in, both at the surface and above. This should set the stage for a slightly cooler night, with lows dropping into the mid-70s across much of the city. The coast, alas, is still going to see pretty normal humidity for this time of year.
Wednesday
This will be a hot and sunny day, with drier air in evidence. Expect highs in the upper 90s, with sunny skies and light winds out of the north. Temperatures should again moderate reasonably quickly as the sun sets, and drier help helps.
Good morning. The Houston region saw its first real taste of rainfall in two weeks early on Monday as a line of storms pushed from north to south through the area. It was hit or miss in the metro area, with some parts of the region picking up as much as 1.5 inches, and others seeing lightning, but no real rainfall. The storms heralded the arrival of a front that will eventually bring some drier air into the region—which we’ll feel this in the morning and evening.
Monday
Some rain chances will linger into this morning, but as drier air moves in we should see gradually diminished precipitation throughout the day. By this afternoon skies should be partly to mostly sunny, and we can expect highs to reach the upper 90s. Winds will be light, but out of the north at 5 to 10 mph. Low temperatures will be a degree or two cooler tonight, but the real effect will be in the “feels like” department, not the actual mercury. This effect will be more pronounced north of I-10 than along the coast.
NAM model forecast for dew points at 7pm CT Tuesday. (Weather Bell)
Tuesday
As more dry air filters into the region we’ll see a hot and sunny day. Temperatures will push into the upper 90s, and probably touch 100 degrees for inland areas. If you’re thinking, this sure doesn’t feel like a front, well, you’re right. But this is how cool fronts in August go. There won’t be much impact to temperatures, but evenings and mornings should feel somewhat drier. Instead of dew points of around 70 degrees, which is very sticky and muggy, dew points around sunrise and around sunset may be be about 10 degrees lower away from the immediate coast. A dew point of 60 degrees is definitely not fall-like, but it’s also definitely not “dog’s breath” weather like we normally get in the summer, either. Small victories, people.
