Matt Lanza

Showers, storms dampen the daytime Fourth in Houston

Good morning, and happy birthday America! It’s a damp one for many of us this morning, though I imagine some others are asking if it will ever rain at their homes. Let’s walk through the forecast.

Now & this morning

As of 8:15 AM, radar shows pockets of heavy rain and thunderstorms gradually pivoting toward Houston from the east. Areas west of the city have seen little rain since yesterday. Eventually some of this will indeed get there.

Areas of heavy rain and embedded thunderstorms are mainly impacting the eastern half of the Houston metro area this morning. This should gradually advance west through the morning. (College of DuPage)

So through about midday, expect rain to become more frequent in the area. The heaviest will continue to hug the coast south and east of Houston.

Rain totals to this point have been manageable, though there has been almost 1.5″ of rain in the last hour along Vince Bayou in Pasadena. An urban flood advisory is posted for southeast Harris, Galveston, Chambers, and eastern Brazoria Counties until 11:45 AM, meaning street flooding is likely in spots.

Total rainfall since last night has been minor in most places, with the notable exceptions southeast of the city. (Harris County Flood Control)

As rain slowly winds through the area this morning, be prepared for more pockets of localized street flooding in areas of poor drainage, along frontage roads, etc., especially south and east of Houston, where it has rained more and is raining harder. We aren’t expect anything too significant today, but be aware of street flooding potential and never drive through a flooded road. We’ll keep you posted if things escalate.

Timing the end of the rain

So expect periods of showers, heavy rain, and thunderstorms for much of this morning and early afternoon, especially southeast of Houston. When does it end? Model guidance has slowed things down a bit unfortunately. The good news is that the heaviest, most concentrated rains should be west of the area by about 2-4 PM. There will be isolated, hit or miss downpours still around the region however through 6-8 PM. I still think most evening events should go off without a ton of issues, but you may want to include an umbrella (assuming that’s allowed at your event) with your other items if you’ll be out and about.

Rain summary

So just to sum things up:

  • Heaviest rains south and east of Houston this morning, with rain rates of 1-3″ per hour possible at times.
  • Rains will expand north and west and everyone should get at least some rain.
  • Localized street flooding is likely in spots, again mainly south and east of Houston.
  • The steadiest rain should taper off this afternoon, but scattered showers will remain in spots (not everywhere) through early evening.

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First round of storms ending southeast of Houston

A somewhat surprisingly wild evening south and east of Houston tonight. As I’m writing this, strong to severe thunderstorms are clobbering Galveston and Jamaica Beach, heading offshore. Lingering storms continue to the west from Texas City across League City into Pearland and Missouri City.

Radar as of 9:15 PM showed heavy rain along the coast, with lingering storms inland south of I-10. (GR Level 3)

Total rainfall has been impressive near NASA, Shoreacres, and El Lago, with three inches falling in an hour in a few spots.

Total rainfall as of 9:15 PM was on the order of 1-4″ in a small area near Johnson Space Center. (Harris County Flood Control)

That has prompted a flash flood warning until 11:45 in that area. Use caution if you’re traveling in that region, as some residual street flooding could occur through midnight.

The storms also produced some awesome skies in the Houston area.

So what’s next?

Weather modeling is actually in decent agreement that this cluster of storms will move offshore and fester for much of the night, before we see things rekindle onshore toward sunrise. Showers and storms should increase in coverage after 3-5 AM as our disturbance swings into Texas. We’ll probably be at peak for coverage of showers and storms in the morning, before everything shifts toward San Antonio in the afternoon.

The best chances and coverage of storms will likely be south of I-10 tomorrow.

So bottom line for the Fourth of July:

  • Heavy rain in the morning, especially south of I-10.
  • More flash flooding of streets possible in the JSC/Webster/Seabrook area.
  • Storms will be noisy with potentially a good deal of lightning once again.
  • Rain ends from east to west by early afternoon for most of us.
  • Late afternoon and evening plans look dry (except well west of Houston toward Brenham and Columbus, where showers will linger til late day).
  • Folks north of Houston may miss out on a lot of the additional rainfall.
  • Additional rainfall: 0.25″ to 0.75″ or less in Montgomery, Liberty, and Grimes Counties and north.1-3″ in Harris, Chambers, Wharton, and Fort Bend Counties. A general 1-3″ with isolated pockets of 3-5″ possible in Galveston and Brazoria Counties.
  • There’s still a degree of uncertainty to this forecast, as modeling could be wrong. Check back in the morning for an update.

More in the morning.

A sloppy Fourth heralds a mini pattern change for Houston

We’ll dive into the forecast for the Fourth of July in a moment. Houston has been plagued by July and August-like heat often since May. Now that we’re in July, the good news is that, at least for a short time, we will reverse course a bit. It will still be hot, but it will actually feel more like May or June than July.

Today

Off the bat, I think today will be mostly trouble-free. Again, if your plans take you east of Houston toward Louisiana, you’ll likely run into showers and storms a good bit of the way beyond Beaumont. Here in Houston, it will be partly to mostly sunny through early afternoon, though clouds should increase later in the day. High temperatures will surge back to the mid-90s once more. I wouldn’t rule out scattered showers or storms later this afternoon or evening for places primarily east of I-45.

Tonight

Our upper disturbance will approach the area later tonight. Ongoing showers and storms in Louisiana may try to hold together as they move into Texas late. Our weather models are somewhat divided on solutions overnight tonight. Possibilities across the Houston area range from “mostly nothing” to “you’re probably going to be roused from slumber at 5 AM because of thunder.” Weather models generally handle these scenarios with mixed results, so there’s a healthy degree of uncertainty here. The radar isn’t exactly lit up in Louisiana this morning, so perhaps this suggests we will need the sun to come up before we get much activity.

But when I look at the “big picture,” meteorologically, I see a strong disturbance approaching overnight. To me, this argues that showers and storms will become more and more likely as the night goes on.

Both the Euro (left) and GFS (right) models suggest a pretty vigorous upper level disturbance nearing Houston by morning, which argues for increasing rain chances later tonight. (Weather Bell)

I would not at all be shocked to see the “roused from slumber” solution win out for some of us. If storms do keep going overnight, it’s not a lock that the entire area would be impacted by them.

So I’ll go with this bottom line tonight: Scattered showers and storms become increasingly likely as the night goes on, with highest odds east of I-45. Expect low temperatures to bottom out in the mid- to upper-70s where it doesn’t rain, and mid-70s where it does.

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A mixed Independence Day coming for Houston

I hope everyone got through the weekend of Saharan dust without too much trouble. We saw a bit of improvement to air quality on Sunday, and we will see further improvement today and tomorrow. It may be unnoticeable by Tuesday. Then we’ll talk rain.

Today & Tuesday

Other than the lingering dust, today will just be another hot one. Look for highs to top off in the mid-90s in Houston, a bit cooler near the coast and hotter inland. It will be mainly sunny. Tuesday will start off similarly. Expect a few more clouds to roll in during the afternoon however. There may be a shower or storm around east of I-45 later in the day. But for the most part, I think Tuesday during the daytime looks good. Any organized storms on Tuesday will be in Louisiana or near Beaumont/Port Arthur. If you’re traveling I-10 east toward Lafayette or Baton Rouge Tuesday afternoon or evening, leave yourself a little extra time.

Fourth of July

Here’s where things get slightly more complicated. We’ve been discussing this since last week, and we have slightly more confidence in how things should go today. A vigorous upper level disturbance will swing across the Gulf Coast Tuesday and into Texas from east to west Wednesday and deliver showers and thunderstorms. Let’s roll through what we expect.

Timing: The start time in the Houston area will vary, but I expect an increasing chance of thunderstorms or showers from east to west on Tuesday night, sometime around and after Midnight, lingering into early afternoon on Wednesday. I think our odds of improving weather go up after 12-4 PM on Wednesday (again from east to west).

Do I need to cancel my plans? If you have July 4th evening plans, I would keep them, as the timing may work out well for fireworks and evening events. The morning and early afternoon will be dicier, so for some area parades, that could dampen things. If you have morning or early afternoon outdoor plans, you may want to have an indoor backup ready to be safe.

How much rain will fall? I believe we should see, on average, one to two inches of rainfall on Tuesday night and Wednesday. There could be a few places that see up to three or four inches of rain, or even a little more.

Total rainfall for Wednesday looks to be in the 1-2″ range on average. Some places will likely see higher amounts, but it’s still too early to say exactly where those will be located. (WPC/Weather Bell)


Flooding? Major, widespread flooding is unlikely from an event like this. As is often the case in Houston in summer, however, street flooding could be an issue in the morning or afternoon, depending on where the heaviest rains occur. Right now I think the most likely window for heavier rain from this system will be from 6 AM through 2 PM Wednesday. That may shift a bit between now and then, however.

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