Mother Nature spared much of the Houston metro area rainfall on Sunday, however with a very moist atmosphere in place we can expect a chance of episodic heavy rainfall for at least the first half of the coming week. This is what happens in July in Houston when there is no high pressure or capping inversion to inhibit tropical rain showers.
Monday, Tuesday and Wednesday
Moisture levels are quite high in the atmosphere, with precipitable water values at 2.0 to 2.2 inches across the region. This means that if you measured the volume of water between the surface and outer space of a certain column of atmosphere, it would have a depth of around 2 inches. This is a lot, and tends to produce rainfall when there are no factors to stop it. For the start of this week there aren’t any—and in fact the upper-level atmosphere favors the development of some storms.
On average Houston should get 0.5-1.5 inches of rain this week, but some areas will see quite a bit more. (Weather Bell/NOAA)
So what does this mean? We’re going to continue to see some potentially stormy days. Last week we talked about how some areas will see mostly sunny skies, some areas mostly gray skies, and some areas will get slow-moving tropical showers. That pattern will continue through Tuesday or Wednesday of this week, with some areas getting 2 to 3 inches of rain in a couple of hours, and others none. Rain chances are likely to be higher (around 50 percent) closer to the coast during the morning, and then the best chances will migrate inland during the afternoon and evening hours. Heavy rains and lightning are the primary threats. The upside of potentially stormy days is that they should limit highs to around 90 degrees.
It’s both a blessing and a curse as a meteorologist to live somewhere that you could almost set a clock to the weather each day. Predictability is great, but they say variety is the spice of life. Houston’s weather has been nothing if not persistent recently. And it looks to continue heading into the next several days.
I don’t see a ton of difference between today and any other day we’ve had this week really. But there are enough subtle differences to make me fairly confident we see more showers around today than we did yesterday. Precipitable water (“PWAT,” a measurement of how much moisture is available in the atmosphere) is flat or down just a bit today versus where it was on Thursday in Houston. PWAT remains elevated north of The Woodlands and east into Louisiana today. While it could rain anywhere as we go into this afternoon, the best odds of cooling downpours will probably be near the coast or Galveston Bay this morning and east of I-45 or well north this afternoon. But regardless of where you’ll be in the Houston area, have an umbrella at the ready today.
Here’s a model derived radar forecast from 12 PM-8 PM today showing widely scattered showers flaring up, especially east of I-45 and to the north of Houston. But that certainly won’t exempt Houston from storm chances today! (Texas Tech)
Temperatures will range from the low to mid-90s where rain is minimal to the upper 80s or lower 90s where downpours are more persistent.
Yesterday I was driving down Interstate 45 near Clear Lake. Within the span of two exits I went from full sunshine, to light rain, to some of the biggest rain drops I have ever seen. It was as if five of these raindrops hit my windshield, and it was covered with rain. And you know what? This is how summer goes in Houston when there’s not smothering high pressure to keep the tropical rain showers away.
Thursday and Friday
Houston will lie near the edge of a high pressure system to end the work week, so we’re likely to see some decrease in shower activity. However, I still expect some isolated to scattered activity, with the potential for some localized heavy rain. With mostly sunny skies, expect high temperatures in the mid-90s.
High pressure builds toward Houston on Thursday and Friday, but it never takes controls. (Weather Bell)
Houston’s weather will more or less remain in the same pattern for the next few days, with some subtle variations, before high pressure begins to assert more control next week.
Wednesday and Thursday
These two days will be similar. The atmosphere remains moist across the Texas coast, but the eastern half of the metro area is a little more so, and that’s probably where the best rain chances will lie Wednesday and Thursday. We can again expect some areas to see hot and sunny conditions, while other parts of Houston see threatening clouds, and some areas actually see some heavy thunderstorms. All told, accumulations shouldn’t be significant enough to cause any kind of flooding. Highs should range from 90 to 95 degrees.
If you’re looking for drier weather this week, Friday’s probably the day. But we’re still going to see a decent chance of showers along with the sea breeze during the afternoon and evening hours. Temperatures will probably be quite warm, with highs in the mid-90s.