Threat of widespread rainfall ends in Houston, so we’re ending our flood alert

In brief: As the likelihood of widespread storms has subsided, we are ending our Stage 2 flood alert. The conditions that brought heavy rains on Saturday have largely passed. Have a great remainder of the Memorial Day weekend, everyone!

It’s Sunday morning in Houston, the radar is quiet, and temperatures are fairly pleasant for late May. After Saturday’s widespread storms and heavy rainfall, it’s a nice change. And I’m happy to report that, in contrast to the start of the Memorial Day holiday weekend, the rest of it should remain pretty calm. Conditions should be calm enough, in fact, that we’re lifting our Stage 2 flood alert.

Temperatures on Sunday morning are quite pleasant for May across the region. (Weather Bell)

Both Sunday and Monday should be partly to mostly sunny. We are likely to remain in the lower 80s today, with temperatures rising to the mid- to upper-80s by Monday. And what of rain chances? They’re probably on the order of 20 or 30 percent each day, perhaps a little higher near the coast and a little lower further inland. The reason is that the impact of an upper-level system is diminishing. Bear in mind that even though each day could be mostly sunny, there still is the chance of a quick-moving shower or thunderstorm popping up.

Tuesday should bring more of the same, but by early Wednesday we are likely to see another disturbance move through. This could bring an additional 1 to 2 inches of rain during the middle of next week. But by then any recent rises on creeks and bayous should have subsided.

Unless the forecast changes significantly for Memorial Day, we are probably going to take the holiday off. Accordingly, we hope you have a great remainder of the weekend, and we’ll be back with a full post on Tuesday morning.

Stage 2 flooding conditions moving through Houston, but we’re nearing the end of this event

In brief: Strong showers and thunderstorms are moving through Houston on Saturday afternoon, creating some flash flooding. The good news is that this mess should exit the area over the next couple of hours. Until then be weather aware.

Hi everyone, just a quick update to note that the “afternoon” round of storms we advertised in this morning’s post is now moving through central Houston. This band of showers and thunderstorms is producing heavy rainfall, and we’re seeing some flash flooding consistent with the Stage 2 alert we have put into place for this weekend.

Houston radar snapshot at 4:32 pm CT on Saturday. (RadarScope)

The good news is that these storms are progressing fairly well to the east-northeast, and should gradually clear the entire metro area by around sunset if not before. Accordingly if you have dinner reservations or other plans later this evening you should feel free to go out. Once these storms end we anticipate a quiet evening and overnight period.

As for Sunday, we expect scattered showers and thunderstorms (probably better chances closer to the coast) but nothing as organized as what we experienced today. Memorial Day probably will have less coverage still, with more sunshine. We will break this all down for you in an update on Sunday morning.

Storms likely on Saturday, possibly severe, but we have some hope for clearing weather by Memorial Day

In brief: Storms are rumbling through Houston during the pre-dawn hours on Saturday, and this is the first of a handful of disturbances we can expect this weekend. Rain chances are a bit lower on Sunday, and we are hopeful that by Memorial Day we’ll see a fair bit of sunshine.

Good morning. Like some of you, I imagine, I was awoken before 5 am by storms rumbling into the Houston area from the west. This pre-sunrise activity is the first of a series of disturbances expected to propagate across the region over the next 24 to 36 hours. We still have some uncertainty about the timing for heaviest rainfall, but I am increasingly hopeful that we will see improving conditions by Memorial Day. Thus, if you were hoping to have a pool day, or a beach day, or otherwise celebrate the holiday outdoors in hopes of a little sunshine, all is not lost.

Houston radar image at 5:54 am CT on Saturday. (RadarScope)

But first, we have some storms to deal with.

The current area of showers and thunderstorms is producing fairly heavy rainfall, and there is also the threat of some severe weather, including small hail and damaging wind gusts. The period between now (5:45 am) and around 9 or 10 am this morning should be treated with caution due to the potential for severe weather as well as pockets of heavy rainfall (we’ve seen rainfall rates of 2 to 3 inches).

So what happens after this round of storms? I think we’ll see a break in activity from the mid-morning to the early afternoon hours. But then, as the atmosphere has time to recharge and we experience daytime heating, another disturbance will approach from the southwest. This will likely spread into Houston during the afternoon or evening hours. Whether it is intense as the storms this morning is not entirely clear—the atmosphere may still be a bit worked over. Some of our high resolution modeling indicates these storms will be strongest along and south of Interstate 10.

We are likely to see more disturbances on Sunday, although timing them is difficult, and it’s not clear how strong they will be. Anyway, expect a healthy rain chance in the vicinity of 60 or 70 percent. By later on Sunday we may be able to lift our Stage 2 flood alert, which is indicative of the waning potential for street flooding and flash flooding.

In contrast to the first part of the holiday weekend, we now think there’s a decent chance of partly sunny (maybe mostly sunny) skies on Memorial Day, with rain chances at or below 50 percent. In other words, most of the day should be fine to celebrate outdoors. Highs will likely be in the vicinity of the mid-80s on Monday, so fairly warm but not in any meaningful way will it be hot.

If the storms this evening look to become fairly strong, we’ll be back with a short update this afternoon. If not, we’ll see you on Sunday morning.

Houston’s heavy rain and storm chances will increase again Saturday night through Monday

In brief: While rain totals across the Houston area have been rather variable (ranging from less than an inch in some spots to over 8 inches in far southern Brazoria County), we expect everyone to participate in rain and storm chances this weekend, especially from Saturday night into Monday. Flash flooding remains a distinct possibility, and our Stage 2 flood alert will remain up through at least Monday.

Rainy pattern check-up

We’re a few days into this relatively significant change to a rainy pattern, and so far, so good for the most part. We’re going to maintain the Stage 2 flood alert through the holiday weekend. I think the rains we saw Wednesday down in Brazoria County (7 inches) exemplify what this setup is capable of.

Rainfall totals from various gauges across the region since Monday. (NOAA)

So far, the northern half of the area has seen a relatively pedestrian 1 to 2 inches (even less in spots), while the southern half has seen 1 to 4 inches on average, with pockets of 5 to 8 inches. We expect another 1 to 4 inches on average over the next week across the entire area. Isolated higher and a couple lower amounts are indeed possible.

For those concerned about the situation in Corpus Christi, Lake Texana has seen about 3 inches of rain, while Lake Corpus Christi has seen about 4 inches of rain so far. Areas upstream of those lakes have received anywhere from 2 to 4 inches as well. By no means does this “save” Corpus Christi from a very bad situation, but it obviously helps buy some time. And any help is great news down there right now.

Today through tomorrow afternoon

Right now, weather modeling is suspiciously calm today and much of Saturday across the area. Obviously, showers and thunderstorms are still possible. But I would suspect most places stay dry as the best “oomph” for storms remains south or offshore in the Gulf. We’ll probably see clouds and sun. Highs may nudge back up into the middle or even some upper-80s after a couple days of lower 80s. There will be plentiful humidity to go along with that.

Saturday night through Monday

If we’re going to get smacked by rainfall, Saturday evening through Memorial Day would be the timeframe I’d be watching closest. A rather vigorous disturbance in the middle and upper atmosphere is going to swing into the Houston area on Saturday evening. This should provide the trigger necessary to get storms off and running. It’s impossible to really say exactly how things are going to setup right now, but expect increasing thunderstorm chances after about 4 PM on Saturday into Saturday night across the Houston area.

Average rain totals over the next week will be about 2 to 4 inches more, but there will almost certainly be smaller pockets that could see substantially higher totals. (Pivotal Weather)

We’ll then need to watch for repeated development of storms and the risk for flash flooding, including in areas that have not seen much rain so far. With moisture in the atmosphere much higher than normal, any storms will be capable of dropping 2 to 4 inches of rain in an hour or so. Any “training” or repeating thunderstorms over the same area means those totals could add up quickly, hence the concern for some localized flooding and our Stage 2 flood alert. More to come on this throughout the weekend as we get more clarity on timing and locations impacted.

Next week

The area will remain under the influence of an unsettled weather pattern and above normal atmospheric moisture. I would expect this on again/off again type rain and storm stuff to continue through much of next week, though perhaps at a slightly slower pace. Either way, what we can say with fairly high confidence right now is that any sustained, strong early summer heat is not in the cards through at least early June.