In brief: Morning rain has thus far been manageable, but repeated rounds of thunderstorms along and on either side of I-10 will likely cause ponding and street flooding in spots this morning and afternoon. Flood Watches remain in effect through evening.

Happening now

One round of heavy rain and storms has exited to our east. Rain totals from that round were manageable in the Houston area and most points north to Conroe. A couple flash flood warnings were needed north of Lake Livingston and back into Huntsville, where totals approached two inches. Now, we’re seeing a west-east line of storms from northern & central Harris County back past Columbus.

Rest of today

This line of storms will likely “train” west to east through the morning and early afternoon. This means repeated rounds of storms basically within 20 miles of either side of I-10. For now, there are enough gaps in between downpours to keep things mostly just annoying and not troublesome. If that continues like that the rest of today, we’ll be fine; yes there will be roadway ponding or localized street flooding but probably nothing much worse.

Eric and I have been wary about things this week because, frankly, most model guidance has struggled. But in general, things seem to be doing what was expected. So, thunderstorms this morning on both sides of I-10. Look for these to continue into early afternoon. Some scattered activity may pop up north of Harris County this afternoon, and we’ll watch for localized downpours up that way. The NWS Flood Watch continues through evening, and our Stage 2 flood alert will continue with that as well. If, for some reason this band of storms shifts farther to the north, it will not take a lot to begin flash flooding. And if for some reason, the rains over Houston remain heavy with fewer breaks, we could see more widespread street flooding. So that’s why we’ll maintain that Stage 2.

Editor’s Note: The National Weather Service Weather Prediction Center issued a discussion while I was editing this post, suggesting that heavier rain over the Houston area was likely through afternoon and could lead to more widespread street flooding. We’ll continue to watch this through the day.

Totals, as you can see from above should be generally 1 to 2 inches, with isolated higher amounts possible. Lower amounts toward the coast and perhaps to the north. Obviously, it’s been pretty rough this week in terms of forecasts and impacts, so continue to monitor the situation, and we’ll post later if anything seriously changes.

Conditions should improve this evening.

Monday and beyond

We finally begin to unwind this disrespectful weather pattern. Temperatures will begin to heat up, and we still expect low to mid-90s into midweek. Rain chances won’t be zero, but they’ll be much lower than they’ve been in recent days.

Even though the rain will quiet down, river flooding will continue this week. One river we have not discussed much is the Brazos. Things have been fine there, but the river is likely to continue rising all week and may even approach moderate flood levels by late in the week.

Beyond Friday, it’s a bit uncertain still, but assuming the river hits 68 feet or so, we’ll begin to see the flood plain get inundated, requiring the relocation of cattle. We’ll monitor this in the coming days; thankfully there’s time to prepare.

In brief: All our available data continues to point toward the arrival of a line of storms after midnight, moving from west to east across the Houston metro area. Because the heaviest of these rains are likely to fall north of Houston, and the high amounts of rainfall already received there this week, we are raising our flood alert for areas along and north of Interstate 10 to Stage 2 for tonight and Sunday.

The overall pattern we’ve been in for the last several days will persist tonight into Sunday. That is to say, the atmosphere is chock full of moisture and unstable. A forcing agent will come early Sunday as a disturbance moves into the region from the west. In recent days the trend has been toward rain events over-performing expectations. So I don’t want anyone to let their guard down just yet.

After midnight we’re likely to see the development of an MCS to the west of Houston. What is an MCS? In meteorological parlance, it stands for ‘mesoscale convective system,’ essentially a large complex of thunderstorms. But when they come through at night I prefer to think of an MCS as a ‘midnight canine stimulant.’ So yeah, it could be one of those nights.

The primary risk is thunderstorms and heavy rainfall. Generally, I think most of the area will pick up 1 to 3 inches, but my concern is the potential for bullseyes of 5 inches, or more. The most probable location for these heavy rains is areas north of Houston, which have already received a foot of rainfall, or more, during the past week.

After the strongest part of the MCS sweeps through, likely around 3 to 6 am for areas such as Katy, 4 to 7 am for downtown Houston, and a little later for the coast, we are likely to see additional showers—on and off—for most of the rest of Sunday. It’s my hope that these will be a little less intense, and a little less organized than the initial push early on Sunday. Matt will have a full update for you tomorrow morning.

You’re probably not going to be believe me, and that’s fine. But I still do expect our pattern to dry out on Monday. We’ll turn sunnier, and hotter for awhile. Rain chances may not go away entirely, but they’ll be significantly diminished.

In brief: A few showers are possible today, but for the most part Saturday should be an okay day. Another round of storms and potential heavy rain arrives tonight and Sunday which could renew street flooding in spots. Quieter, hotter weather arrives next week.

For the latest flood gauge information, visit the National Weather Service or Harris County Flood Control websites.

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The East Fork of the San Jacinto has crested at New Caney but will only slowly fall.

To the south, the West Fork of the San Jacinto at Humble is expected to crest on Sunday and remain in major flood until at least Monday or Tuesday.

The San Jacinto will continue in major flood downstream as well, with very fast flow passing barges near I-10 which could lead to some loss of mooring.

Unfortunately, the Trinity in Liberty County is going to remain just shy of record levels for several days, allowing major flooding to continue.

Please continue to heed the advice of local officials and never drive around barricades.

Saturday morning & afternoon

The good news this morning is that radar is vacant around Houston for the first time in some time. There are a few storms passing through the Beaumont-Port Arthur area up toward Jasper, but they’re moving offshore or into Louisiana. I would expect the morning to be fine in most areas.

With daytime heating, scattered showers and a few thunderstorms should begin to develop this afternoon. These will be hit and miss; some people will see downpours, others will be dry. I expect these will move along at a decent pace. The belief is that both the movement and the actual rain rates with these will be a bit lower than we’ve seen in recent days. The best chance for this will be north of I-10 after 12 to 2 PM, which isn’t great news for areas dealing with river flooding, but hopefully they don’t add much to problems. We should make the low to mid-80s today.

Tonight & Sunday morning

Here’s why Flood Watches remain in effect. Storms this afternoon in Central and West Texas will slide east with a disturbance and likely congeal into a well organized area of rain and thunderstorms. This should arrive in our area tonight, after 12 to 2 AM or so. There are still questions regarding how this plays out. Some model guidance shows less organization to the storms and more scattered type activity. Other data suggests it will push through at a good clip. And yet other data has sort of a repetitive scenario, where we see multiple rounds of storms, much like occurred on Friday and Thursday.

For now, a widespread half-inch seems reasonable for Houston and points south, with 1 to 2 inches north of Houston. There will almost certainly be higher amounts, with the most likely areas being north of Houston. In those spots, 2 to 5 inches of rain could fall on top of already saturated ground, leading to rapid street flooding. This would be mostly a concern in the northern part of Harris, Montgomery, and Liberty Counties and points north. If you have outdoor Sunday plans, it would be best to have an indoor backup plan available.

In addition to rain, some storms could be strong with a couple perhaps producing some modest hail or strong winds.

Monday & next week

We expect the pattern to begin to transition beginning Monday into the forecast heat for next week. While a few showers or storms are possible, significant weather is not expected on Monday. The main story will be heat next week, building through the week.

Heat will build up to “major” levels, as classified by the National Weather Service, with low to mid-90s likely for highs by Wednesday and/or Thursday. Given that this will be our first real heat of the season, give your body some extra time to adjust. We’re not used to it just yet. We’ll have more tomorrow, or later today if necessary on the rain.

In brief: An unexpectedly intense flooding event has engulfed areas north of Houston this week. We discuss that, and the ongoing forecast for the weekend, which could see an additional round of storms on Sunday before things start to dry out next week.

If you live south of Interstate 10, you may be wondering what the fuss is all about in regards to heavy rains this week. Much of this area has received 2 inches or less over the last five days, and certainly not experienced anything remotely close to flooding conditions. However, looking at the rainfall accumulation map below, we can see that eastern Montgomery County got rocked with 12 inches of rain, and further to the north, Walker and San Jacinto counties recorded 15 to 20 inches of rainfall. Some of this came very quickly, with high rainfall rates.

And so we have a situation where much of the region is just fine, but there is terrible flooding ongoing along the San Jacinto and Trinity river basins. The most dangerous flooding is occurring along the East Fork of the Jacinto River, but the entire north and northeastern parts of the Houston metro area are dealing with significant and ongoing flooding.

What’s next

So what happens next? After today’s showers, we should see a reprieve for the rest of this afternoon and evening. Our record for predictions this week has been pretty shoddy, but at this point I only expect development of sporadic showers on Saturday morning. And most of Saturday, frankly, looks mostly rain free. At this time I think we’re unlikely to see more than scattered showers and thunderstorms, with accumulations not amounting to much.

Unfortunately, it does appear as though a final storm system will work its way toward the area later on Saturday night, or Sunday morning. This atmospheric disturbance will likely bring widespread showers and thunderstorms on Sunday morning-ish, and perhaps throughout much of the day. As a rough guess we’re looking at additional accumulations of 1 to 3 inches, with the potential for higher totals. This will, unfortunately, only exacerbate ongoing river flooding.

By Sunday night high pressure really should begin to assert itself, and most of next week looks sunnier, and hotter. Rain chances look lower for most of the week, although perhaps not zero.

Given the unpredictability of the storms we’ve seen this week, and the threat of additional rain on Sunday, we’re going to continue with posts each morning this weekend to keep you updated. Thanks as always for reading, and for your patience as we have struggled to grapple with a challenging forecast that has been more miss than hit.