In brief: Houston will see high rain chances through the coming weekend, but the threat of heavy rainfall will be particularly acute during the next four days. We have issued a Stage 1 flood alert for now through Thursday, which indicates the potential for street flooding. Basically, you’ll need to pay attention to the weather this week.

A wet pattern

As we discussed on Sunday, the overall setup for this week favors moderate to heavy rainfall, with the potential for some street flooding. The upper Texas coast will lay beneath a trough in the upper atmosphere, and our atmosphere will be laden with moisture. Tuesday and Wednesday look to have the most favorable setups for heavy rainfall, but chances will remain high from now until Thursday.

In terms of overall accumulations, I think the Houston area will pick up between 2 and 6 inches of rainfall this week. My biggest concern lies near the coast, with access to the most moisture from the Gulf of Mexico. This is where we could see some bullseyes above 6 inches of rainfall this week. To account for the threat we’ve issued a Stage 1 flood alert for the entire region, which produces street flooding. We’re closely monitoring the situation to determine whether we need to elevate this to a Stage 2 flood alert for coastal counties.

In Houston, roads are designed to flood during heavy rainfall. This is annoying, but in a generally flat region prone to heavy tropical rainfall, roads become arteries by which water is carried into streams and bayous, and thus eventually out into the Gulf of Mexico. So during intense rainfall, roads will briefly back up. This is why we repeatedly stress to not drive into high water. The bottom line is that, this week, we will need to be weather aware. Check the radar before you leave. At this point we don’t anticipate significant home and business flooding, but the heavy rains will likely cause some inconveniences. We’ll be here to try and pinpoint the times of greatest threats. If warranted, we will post multiple updates a day.

Monday

Of the next four days, Monday likely presents the least threat of widespread, heavy rainfall. The chances today actually look best along the coast, from Matagorda to Galveston Bay; and inland, from Montgomery County northward. The most likely scenario is that each of these boundaries remain far enough apart that the central Houston region, including downtown, remains relatively quiet today in terms of rainfall.

However, there is a slight chance the boundaries meet over downtown, near Interstate 10, in which case things would become more active over the central Houston area. Like I said above, keep a good radar app like RadarScope handy. Generally I think things will quiet down this evening and overnight. Highs today will reach about 90 degrees, or so, given the extent of rain-cooled air at your location.

Tuesday and Wednesday

Both of these days should bring waves of moderate to heavy showers through the Houston area. The first of these could arrive some time on Tuesday morning, pushing from south to north, and afterward we should see additional impulses with consistently high atmospheric moisture levels. With mostly cloudy skies, these days should see high temperatures only in the 80s—a remarkable contrast to last year when we were consistently hitting 100 degrees in late July. Overnight lows will be in the mid-70s.

We’ve had some questions about severe weather, and while we can’t rule out some high winds in stronger thunderstorms, generally the wind, hail, and tornado threats will be quite low this week. Our major concern will be heavy rainfall, and rates above 2 inches per hour that can quickly back up streets.

Thursday

We’ll remain in a very wet pattern on Thursday, but forecast models indicate that the impetus for the highest rainfall rates will back off a bit. Regardless, expect widespread showers, with highs in the 80s. At this point we’re planning to expire our Stage 1 flood alert on Thursday night, but we’ll of course be monitoring this closely.

Friday, Saturday, and Sunday

Elevated rain chances will remain through the weekend, but the threat of heavy rainfall should continue to diminish. If you have outdoor plans, I would have a backup plan. Daily rain chances are on the order of 60 or 70 percent, with mostly cloudy skies. Expect highs in the upper 80s to about 90 degrees.

Next week

Rain chances diminish further next week and we’re likely to see a sunnier pattern. As this happens, expect our highs to return to the mid-90s. I don’t mean to terrify or threaten anyone by saying this, but the month that comes after July in Houston is August. And well, August is the worst month of the year as we can expect heat in abundance, and the tropics to become active again after this mid-July lull.

In brief: We are issuing a Stage 1 flood alert for the entire Houston metro area, through Thursday, to account for the potential of street flooding. Much of the Houston area should pick up 2 to 6 inches of rainfall through Thursday, with a few areas seeing higher bullseyes. This post describes what to expect, when to expect it, and explains why this is happening.

A setup for rainfall, some of it heavy

In the big picture for the coming week, the upper Texas coast will lie between two high pressure systems. As anyone who has lived in Houston for any time knows, high pressure during the height of summer means sunshine and hot temperatures. And it also means sinking air, which precludes the development of showers and thunderstorms.

Conversely, when Houston lies beneath a trough of lower pressure—as we will this week—the opposite occurs. This environment promotes rising air, and thus all of the moisture at the surface can ascend into the atmosphere, cool and condense into clouds, and lead to showers and thunderstorms. Thus we will see a wet pattern this week, beginning on Monday. Showers and thunderstorms are likely on the daily, with heavy rain definitely possible as we are open to moisture streaming in from the Gulf of Mexico. We cannot rule out severe weather, but it seems unlikely with the heavy rains.

To account for this rainfall, we are issuing a Stage 1 flood alert on our scale (read more about our flood scale here). Generally, this means you can expect the potential for nuisance street flooding during the heaviest rains, the kind you typically see on some frontage roads or the like. However, we do not expect this to be a widely disruptive event. Overall, I expect much of the Houston area to pick up 2 to 6 inches of rainfall through Thursday, with a few areas seeing higher bullseyes.

As a bonus, beginning Monday, we are likely to see cooler daytime temperatures, with clouds and rain-cooled air limiting highs in the 80s. That’s a rare treat in July, and definitely a silver lining amongst the cloudy skies for the coming week. As for the humidity, well, bless your heart for expecting anything but the usual Houston steaminess in July.

What follows is not so much a daily forecast, but a guide to which days are likely to see the heaviest rains.

Sunday

Showers will be of a more scattered nature today, although areas near the coast are probably more likely to see rainfall than not. Overall conditions should not be particularly disruptive so go about your plans as usual. Have an umbrella handy this afternoon, however.

Monday and Tuesday

Both of these days will see widespread showers and thunderstorms. These should be nuisance showers for the most part, although a few storms should bring heavy rainfall. I do not recommend any outdoor plans, but in terms of traveling around Houston I don’t anticipate any major impacts.

Wednesday and Thursday

The potential for heavy rainfall looks to be highest on Wednesday through at least Thursday morning. For these days there could be some delays in getting to work, and traveling around the city. Again, we don’t anticipate major, sustained flooding. But you know how Houston thunderstorms can be. They can drop a deluge of rain in a short time, so some areas will see some fairly gnarly conditions over shorter periods of time. Basically, you’ll need to be weather aware these days.

Friday, Saturday, and Sunday

Rain chances lessen by Thursday night or so, which is why we’re presently planning to end our Stage 1 flood alert on Thursday night. But the possibility of rain is definitely not going away this weekend. Expect the rainy pattern to continue, albeit with less intensity and perhaps better odds to see some sunshine. Next week, however, does look hotter and sunnier.

A note of thanks

I want to thank Matt for covering the site all last week while I attended a family reunion in Michigan. I don’t want to brag too much, but it felt amazing to go running with temperatures of 60 degrees and low humidity. It offered a reminder that, in just a couple of months, we can look forward to some of the same here. Speaking of which, when we stepped off the plane at Hobby Airport and felt that first flush of Houston air, my family immediately knew we were home. We should come up with a word for what it’s like to experience that first taste of Houston humidity when landing here. Suggestions?

In brief: A smattering of showers and thunderstorms will be with us today and tomorrow. More scattered storms are in play for Sunday. And then widespread rain and thunderstorms will be the forecast for much of next week, with locally heavy rain, some flooding, gusty winds at times, but also cooler temperatures.

A quick housekeeping note: The latest version of the Space City Weather app is available for Android and iOS now. Dwight will have a post out later this morning explaining the changes that went into this version and how you can report any bugs (not just the mosquitoes landing on your phone inside your house). As a side note, since beginning this journey with Eric almost 10 years ago now, it’s pretty cool to see how far this has come. No app is perfect, but I am proud of ours, and I hope you find it to be useful.

Today

We have two clusters of storms this morning in the area. The first is to the west of Sugar Land, dropping across Wharton County. A second area of storms extends from Kingwood east toward Beaumont. Those should continue to drop southward and gradually weaken. Look for a few more showers and storms to form this afternoon.

After failing to hit 90 yesterday thanks to cloud cover and rain-cooled air behind yesterday morning’s system, highs will top off in the low-90s today. It actually felt kind of nice yesterday!

Weekend

Saturday actually looks like a fairly decent day overall. Yes, there will be a chance of showers or a thunderstorm. But on the whole, rain chances will be at a relative low compared to what’s ahead Sunday and beyond. So look for a smattering of afternoon showers and highs in the low-90s.

Sunday looks a little busier. We’ll have a little more moisture and enough support for more in the way of scattered thunderstorms. Lows will be in the 70s, with highs around 90 or a little hotter depending on rainfall.

Monday through Thursday

If you have plans next week that involve anything outdoors, make sure you also have an alternative lined up. It looks like a chaotic, busy week in the atmosphere over Texas. We will have numerous vigorous disturbances pushing across Texas with a large trough in the upper atmosphere. This means numerous daily rain chances, locally heavy rain, a few strong storms, and cooler temperatures than normal.

It remains very difficult to predict exactly when the heaviest rain will be. Right now I’d hone in on later Monday or Tuesday and again later Wednesday or Thursday for the best odds, but that may shift around a bit. What we do know is that the amount of moisture available in the atmosphere will be 100 to 150 percent of normal, which typically translates to at least a couple rounds of heavy rainfall. The Weather Prediction Center currently has forecasts for excessive rain out through Tuesday and has the region at least in a marginal risk (level 1 of 4) each day. I would say to expect an additional 3 to 6 inches *on average* across the region. Some places may see a bit less than that, but it’s conceivable that a couple places will see more with enough storm activity through next Thursday. We will likely have to dust off the flood scale again Sunday or Monday and keep it up through Thursday or Friday. This would be primarily for street flooding concerns. Check back with us for more perhaps on Sunday.

While thunderstorms are likely, severe weather is merely possible, not likely. Any severe storms should be isolated and brief. There will be gusty winds at times with any storms, and severe or not, that may be both unsettling to you and the power system. So periodic temporary power outages can’t be ruled out through next week. I get the anxiety, trust me.

As noted, cooler weather will arrive next week thanks to the clouds and rain.

For example, on Wednesday, like some people’s taste in music, we will struggle to get past the mid-80s. These suppressed daytime highs will continue into late week before we slowly rebound next weekend. Nighttime lows will not necessarily play along, as they should remain in the 70s.