One more day of healthy rain chances in Houston before we tap the brakes

In brief: Houston should have one more round of fairly widespread thunderstorms today, especially closer to the coast before things start to ease up closer to what’s typical for June. The relatively mild weather of this week will revert back to typical early summer fare heading into next week.

Today

After yesterday’s widespread rains, we get one more crack at the free car wash today. Things are starting off quiet this morning. That should change as the morning progresses. We’ll have a couple showers pop up along the coast over the next few hours. That will evolve into more numerous downpours and thunderstorms after 10 or 11 AM. This will be especially true along the coast and just inland, so Highway 59/I-69 is kind of our demarcation line today. South and east of there, higher rain risk, north and west lower rain risk.

(NWS Houston)

A flood watch is in effect for coastal counties between Matagorda Bay and Louisiana today. These areas will be more susceptible to the heaviest rains. We will continue the Stage 1 flood alert as well for the rest of today. The Matagorda area was hardest hit yesterday, but today I would watch closer to Galveston and on the island for some healthy street flooding risks. These storms will be capable of dumping 2 to 4 inches in an hour.

So, storms become widespread at the coast after 10 or 11 AM and some additional more scattered activity spreads inland to the northwest from there. Rains should dissipate after sunset.

Saturday & Sunday

On Saturday, the trough that sits over the Arklatex today will move into the Mississippi Valley to our east. That should reduce the overall support for widespread thunderstorms like we’ve had since midweek.

What does this mean? Well, we should revert to more typical summertime weather. I would expect to see some showers or a couple thunderstorms develop each day from late morning through afternoon along the sea breeze as it slowly migrates inland from the Gulf. Many of us will see nothing at all, but a few will receive the often-welcome cooling downpour on Saturday or Sunday. Coverage may be a smidge higher on Sunday than Saturday. But anyone planning to partake in outdoor activities will probably only have to briefly dodge a shower, if anything at all.

Sunday’s high temperatures look like early summer. (Pivotal Weather)

It will warm back up though. We should reach the low-90s with a couple mid-90s here or there. Morning lows will be in the upper-70s.

Next week

High pressure over the Southwest will flatten out while a new area of high pressure builds west across the Gulf Coast toward Texas. We’ll probably keep Monday much like Sunday or Saturday, but Tuesday and Wednesday could see slightly increased rain chances before we probably shut off the sprinklers for a couple days later next week. Highs will generally remain in the lower-90s, close to normal for mid-June.

The worst of today’s heavy rainfall is over, so we’re stepping back to a Stage 1 flood alert

In brief: With the most potent rain-making storms now moving offshore, we are returning to a Stage 1 flood alert for the entire Houston region. Heavy rainfall remains possible on Friday, although we don’t expect storms to be quite as organized as they were today.

Hi everyone. Just wanted to write a quick post to note that the atmosphere is pretty well worked over, and that the strongest line of storms has now moved mostly offshore. As a result of this, we expect a fairly quiet afternoon and evening in the Houston metro area. We still expect to see some light to moderate showers for a few more hours today, but the trend will be one toward gradual clearing of the area.

Houston radar image as of 11:54 am CT. (RadarScope)

If you’re looking for a bright spot, look no further than temperatures, which as of noon are hovering around 70 degrees for most of the region. We don’t see midday temperatures like this often in June. I expect highs to nudge upward, toward the upper 70s, before evening and slightly cooler overnight temperatures return.

I think conditions, in terms of rainfall, will generally be fairly calm overnight. However, by daybreak we may start to see some additional showers building in from the southwest, and we are likely to see another round of storms from the mid-morning through the afternoon hours across the region. I don’t believe these storms will be as widespread as today’s – in which some locations south and east of Houston picked up 6 inches – but the potential for heavy rainfall remains. We think a Stage 1 flood alert should cover us, but we’ll be keeping tabs on the situation just in case.

Heavy rainfall event ongoing in the Houston region, conditions should ease later today

In brief: We have expanded a Stage 2 flood alert to cover the entire region today as a storm system passes through. The greatest likelihood of flooding appears to be to the southwest of Houston, but all areas will be vulnerable this morning.

Unfolding flooding event

As we look at the radar this morning we have one band of persistent storms over eastern Houston which has dropped as much as 3 inches of rain over Channelview, Baytown, and other locations since midnight (a flash flood warning is in effect for these locations until 7:30 am today). Much of the rest of the region has been spared, but additional storms loom to the west of our area, and we expect the potential for flash flooding through about noon today. Not all areas will be affected, certainly, but please take care driving into stronger storms, and do not attempt to drive through high water.

Strong storms are firing up to the west of Houston and will move through this morning. (RadarScope)

The strongest storms should move into the Houston region during a time period from around 7 am to noon, after which the heaviest rains will likely reach the coast and begin to push off shore and well to the east of Houston. During this morning we now believe the heaviest rainfall will occur along and south of Interstate 10, and are particularly concerned about the southwest quadrant of the Houston metro area. Much of our modeling predicts that Wharton, Brazoria, and southern Fort Bend counties are at risk of picking up 5 to 10 inches of rainfall.

Closer to Houston, particularly within the city limits and to the east of Interstate 45, totals should be less. Generally, most locations should pick up 1 to 4 inches of rainfall, but there will be the potential for higher bullseyes. Given that this storm system has the ability to produce high rainfall rates, streets may back up quickly and flash flooding is possible. For this reason, we are expanding our Stage 2 flood alert to cover the entire Houston region, which includes all surrounding counties. We should be able to drop this flood alert back to Stage 1 this afternoon.

Thursday

As noted above, we are seeing an atmosphere laden with moisture interact with a potent disturbance this morning, creating favorable conditions for heavy rainfall. The strongest storms should end by noon, but some isolated showers could persist into this afternoon. As a result of the rain and cloud cover, high temperatures today should top out in the mid-80s. Lows tonight will drop into the 70s, with a slight chance of showers and storms.

Friday

Some additional storm development is likely on Friday, and conditions may be most favorable for this closer to the coast. However, we cannot be sure about this. Overall, the pattern is a little bit less supportive of strong storms on Friday, and I don’t expect things to be as widespread or significant as Thursday, but the threat of heavy rainfall will nevertheless be there. Highs will be around 90 degrees, as skies should be partly sunny.

Temperatures will return to the lower 90s in Houston by this weekend, with muggy nights. (Weather Bell)

Saturday and Sunday

The weekend will continue to see a chance of showers and thunderstorms, although at this point I expect them to be more isolated in nature rather than widespread. So they should be hit and miss, and there should be mostly sunny skies for much of the day. Expect high temperatures in the lower 90s. If you have outdoor plans, there’s a chance they may be fine, although you can expect soils and fields to be sodden from this week’s rains.

Next week

I expect this pattern to continue for much of next week, with a decent chance of showers and thunderstorms on a daily basis to go along with mostly sunny skies and high temperatures in the lower 90s. At this point I don’t see the potential for significant flooding, as these will more likely be passing showers driven by the sea breeze with lower accumulations. But we’ll see, as it is June, when we are prone to higher rainfall rates. I do expect a chance of rain to remain in our forecast for awhile, perhaps the rest of the month, rather than seeing a robust ridge of high pressure cover the area.

We will update this forecast as needed today. Please be safe in the wet and inclement weather.

Strong storms likely to hit the Houston region Thursday morning: Stage 2 flood alert for areas west of I-45

In brief: Our confidence is increasing in the likelihood of heavy rain across the Houston metro area on Thursday morning, perhaps around sunrise or a few hours later. Flash flooding is possible in the strongest storms.

The overall forecast from the post we published this morning remains more or less on track. However, our confidence is now very high in impactful storms pushing into, and through, the entire Houston region on Thursday morning. Although we still have some questions about timing and placement, it is clear that a serious line of storms will go through.

The Houston area faces a risk of excessive rainfall on Wednesday night and Thursday morning. (NOAA)

Tomorrow morning, before dawn, there may be some isolated or scattered showers and thunderstorms across the western half of the Houston metro area. However, the main event is likely to be a line of storms that forms northwest of the region and sweeps into the city. In terms of timing, we think this mass of storms will impact areas such as College Station around 5 am to 8 am, before pushing into central parts of the region (including the area inside Beltway-8/Sam Houston Tollway) between 8 am and noon. After this the line will likely continue down to the coast and exit the area to the east.

The models disagree on where the most impactful rains will be: Brazos County, Montgomery County, or Western Harris County are all possibilities, for example. But the bottom line is that we are going to mix a potent disturbance with an atmosphere with a lot of moisture. This is fertile environment for high rainfall rates, which can quickly back up streets and lead to flash flooding.

As a result of this we are elevating our flood alert to Stage 2 for areas along and west of Interstate 45.

Although we cannot entirely rule out other forms of severe weather, flooding is the main threat from these storms. Most of the region will likely pick up 1 to 4 inches of rain in a couple of hours, but there will almost certainly be higher bullseyes where 5 to 8 inches could fall in a very short period of time. In short, be prepared for disruptions to travel plans on Thursday morning, and be weather aware. We will have a full update for you early tomorrow morning.