An active weather pattern over Texas will slowly increase our shower chances each day this weekend. Generally, the deeper into the holiday weekend you go, the better the rain chances will become. Today and tomorrow probably won’t be too bad. Sunday could see heavier rain west of Houston and Monday could see more widespread coverage of thunderstorms in the Houston area. Specifics beyond “showers and storms are possible” will be hard to come by more than 12 to 18 hours in advance; such is the nature of weather patterns like this. Let’s walk through each day and tell you what we know at this time.
Today
Expect some clouds and some sun today, with sun probably becoming more dominant as we roll toward afternoon. There’s a little more moisture available today, so we will at least mention that a shower or storm is possible. As I am finishing writing this, it’s evident that some showers have popped up out toward Wharton County and up through Columbus, well west of Houston but somewhat sudden and unexpected this morning. We think most activity should be spotty (call it like 10 to 20 percent or so), and storms should be very much the exception, not the rule today but hopefully these morning showers are not a harbinger of a busted forecast to come. We will see!
It’ll be hot and humid with highs around 90° or so for the fifth day in a row.
Tonight
Another round of showers and storms in North Texas may just have enough “oomph” to hold together as it drops south and east late tonight. We could see a shower or a thunderstorm, mainly north of Houston after 3 AM or so. For most of us? Just mostly cloudy with a slight shower chance or some mist. Lows will be in the 70s.
Saturday
On Saturday, the best ingredients for thunderstorms remain mostly inland or to our west, which means Hill Country may be the favored area for more numerous showers. We’ll call it a spotty day once again for Houston with a few showers or storms possible, once more being the exception rather than the rule. Odds of storms may go up a bit as you go to the north and west of Houston.
Rainfall between Saturday morning and Sunday morning is likely going to be most significant west of I-35, or way back in Hill Country or parts of South Texas. For Houston? Probably not too significant. (NOAA via Weather Bell)
Look for another hot day with highs likely staying in the upper-80s or low-90s under partly to mostly cloudy skies.
Sunday
So on Sunday, the best ingredients for storms drift a little closer to Houston. While we think the coverage of storms will still be highest to the west of Houston, there should be slightly better odds for much of the area to see storms. I would say storm chances jump up close to 50 percent on average for Sunday afternoon, higher west of I-45, lower east of I-45.
Storm chances on Sunday will still be highest north & west of Houston, but most of the area will be at least at risk for some storms Sunday afternoon. (NOAA via Weather Bell)
Sunday’s storms could also be better organized than what we see Saturday in Texas, so heavier rain is possible. We would say that areas west of Grand Parkway up through Conroe stand the best chance of heavier rains impinging on plans Sunday afternoon. But again, specific details are tough to pin down, so most of the area has at least a chance at some storms Sunday.
A muggy Sunday morning in the 70s will give way to highs only in the mid-80s, maybe upper-80s with clouds.
Storms this afternoon were expected to dump heavy rain in a few small areas around the region. What we are seeing is something more robust than that, as widespread heavy rain and some areas of street flooding are ongoing. Flood Advisories are posted for the entire Houston area, and the Pasadena area is now under a Flash Flood Warning through 5:15 PM.
Areas south and east of Houston, including Pasadena have been hardest hit by heavy rain, and a flash flood warning is posted until 5:15 PM there. (NOAA)
Radar as of 3:15 PM shows a cluster of heavy rain that has migrated west over most of the Houston area.
Radar shows widespread heavy storms in the Houston metro area, with the heaviest rain south and east of the city and also migrating westward. (RadarScope)
This is basically going to need to rain itself out now over the next 3 to 4 hours. Pasadena has been fairly hard hit with nearly 4 inches of rain so far.
Rain totals of nearly 4 inches have occurred so far today near Pasadena. It is still pouring there. (Harris County Flood Control)
For the sake of simplicity I’ve just shown part of the metro area above. You can always check rain totals over various times over the larger area at the fantastic Harris County Flood Control gage site. Some folks will see little to no rain (especially northeast of IAH Airport and perhaps well south toward Lake Jackson and Freeport). Others may tally 5 to 6 inches or more when all is said and done this afternoon.
So heavy rain, storms, and street flooding are likely in many spots through 7 PM. Storms will fade after that. We enter a quiet period later this evening and into the early overnight.
Round 2 of storms will arrive here later in the overnight. The timing of the next wave of storms has sped up since this morning, and it now appears we will see heavy rain and storms resume after 2-3 AM (about 2 to 3 hours faster than expected this morning). Below is what one model thinks radar will look like at 3 AM Saturday.
The HRRR model suggests a large cluster of heavy thunderstorms will plow through the region between 2 and 5 AM Saturday. (Weather Bell)
Other models vary a bit on timing and orientation, but all show the entirety of the region seeing a period of heavy rainfall. Another 1 to 3 inches of rain will be possible with this. This would likely lead to widespread street flooding, especially around the hardest hit areas so far with today’s rains, where the ground will be very saturated.
As for Saturday afternoon? There is a chance we see another round of rain and storms, but we still do not have much confidence in details yet to determine whether we need to be concerned or not. We will update you either tonight or early Saturday morning. A reminder that we went with a Stage 1 on our Flood Scale this morning. See our earlier post for more details on that. Stay safe, and remember to never drive through flooded roadways.
On Thursday, we expected a handful of thunderstorms to develop across the area, though it seemed likely most of us would be dry. That’s ultimately what seems to have happened in Southeast Texas, with one very glaring exception.
Radar estimates of 8-10″ of rain were observed yesterday east of Beaumont in Orange County. Heavy rain also fell in the Beaumont area. (RadarScope)
The area east of Beaumont, specifically between Vidor and Orange in Orange County was deluged on Thursday with up to 10″ of rain falling near Bridge City. While weather modeling did indicate thunderstorms were possible, none of the models that we saw remotely suggested this amount of rain would fall.
This brings up a key point I like to remind folks of this time of year in Texas: No matter how many models we look at, or how clear we try to be when it comes to forecasting rainfall totals, the reality in Texas is that under the right (wrong?) meteorological conditions, 4, 6, 8, 10 inches of rain can fall on any given location. We are in a very humid air mass, with yesterday’s precipitable water values running 150 to 200% of normal in parts of the region. In English, there was a lot of moisture available to dump heavy rain. Weather models won’t always tell the whole story. If a couple slow moving storms get going, they can easily dump 1 to 3 inches an hour on a location for several hours in this pattern. That’s what unfortunately happened in Orange County yesterday.
We don’t expect that to occur again today, but there will likely be some heavy storms around in a few spots. A Flash Flood Watch has been issued by the National Weather Service for all of the Houston metro area and coast from tonight through Saturday. We are growing somewhat more concerned about Saturday’s potential for widespread street flooding across the area, something that would be akin to a Stage 1 flood event for the area on our Space City Weather flood scale, which we describe in detail here.
Remember, our scale is primarily to set your expectations at a high level for the type of flooding we could see. It’s not a guarantee of what will happen specific to your backyard. We may adjust this later today or tonight as new data warrants.
Summary
The forecast over the next 24 to 36 hours is very complex. Here’s a quick summary of what we’ll go through in detail below:
Today: Most locations see a few passing showers or no rain at all. However, a handful of smaller locations in the Houston metro area have the potential to see slow moving downpours capable of producing 2 to 4 inches or more and flash flooding.
Tonight: Rain ends, then rain chances increase rapidly again after 4 AM, with heavy showers and thunderstorms likely everywhere by sunrise.
Saturday: Heavy morning storms likely with torrential downpours. Street flooding possible, if not likely. Storms should gradually end in the afternoon with a mostly quiet night.
We expect total rainfall to average 1 to 4 inches across the region. There will be many places that come in closer to 1 to 2 inches, but we also expect a couple locations to see perhaps 6 inches or more when all is said and done.
The forecast of total rainfall by Sunday morning will be 1 to 4 inches on average, with a few smaller locations likely to see in excess of 6 inches. (Weather Bell)
Today
Things are quiet this morning, with just a few isolated downpours in the Beaumont-Port Arthur area again.
For the Houston area, let’s call it about a 50 percent chance of showers and storms today. The problem today is the same as above in that if any storms develop and drift slowly, we could be talking about some very heavy rain for isolated spots. And some of the higher resolution models we use suggest this is a possibility around Houston. So while many of us will only hear some thunder and see little to no rain, a handful of smaller locations could see 2 to 4 inches of rain or more this afternoon. I don’t want to try and specify where those bigger ticket totals will be exactly, but based on this morning’s model guidance, they would occur somewhere in western Harris, Fort Bend, or Brazoria Counties.The Weather Prediction Center has us in a “Slight Risk” of excessive rainfall today.
A “Slight Risk” of excessive rainfall is shown over Houston today, which means flash flooding is a possibility. (NOAA)
This just underscores that flash flooding is a possibility today.
High temperatures will likely peak in the mid- to upper-80s this afternoon.
Tonight
We expect any lingering showers or storms to end around or just after sunset. Through the first part of the night, things should be quiet. Meanwhile, severe storms in West and Central Texas will likely congeal into an organized complex of thunderstorms and heavy rainfall and work east out of Hill Country overnight. We could begin to see showers develop out in front of that in the last few hours of the night. The general rule is that as we go from this evening to midnight, rain chances dwindle to near zero. From midnight through 6 AM Saturday, rain chances begin to escalate again, rapidly after about 4 AM. Lows will be in the 70s.
Saturday
As noted above, the broad summary is that a complex of heavy rain and storms will plow through the entire Houston area on Saturday morning. Some of the storms could be severe, with strong winds being the main concern. But the main concern on Saturday will be street flooding.
One forecast model’s depiction of what radar could look like around 7 AM Saturday shows a complex of strong to severe storms with torrential rain moving across Houston. (Weather Bell)
We should all receive anywhere from 1 to 4 inches of rain with that, though some higher amounts will be possible. Street flooding seems to be a reasonable possibility. Where things would get dicey is if the complex of storms slows down and allows for new storm development or “training” (storms moving over the same areas) on the backside, something we can’t entirely rule out. If that happens, those areas would see another 1 to 3 inches or more of rainfall and more widespread, significant street flooding would become a possibility.
Given how poorly models have performed with specifics historically in these events and how much moisture will be available, I don’t want to try and tell you that we know exactly who will see how much rainfall. We don’t. I expect that we will have a better handle on this later today, and we may post an update this afternoon or evening to clue you into what has changed since this morning.
After a pair of pretty nice days across Southeast Texas, we’re waking up to a warm, humid, mostly gray one today. But that will change. For those of you looking for last hurrah of really comfortable weather before summer, soak up this weekend.
Today & tonight
The region has had some gusty onshore winds overnight. Galveston has seen some wind gusts close to 40 mph since 2 AM, while inland locations have seen 25 to 30 mph gusts at times. Winds should diminish a bit through the day today before picking back up from the offshore direction tonight.
As far as weather, we’ll call it cloudy this morning. We may see more sunshine break out by late morning or afternoon, and it will remain warm to hot and humid. While a few showers or sprinkles could occur this morning, most of us will probably stay dry. The cold front itself will approach the region this afternoon. Right now, we’re expecting a broken, disorganized line of showers and a couple storms to drop into the northern suburbs 1-2 PM this afternoon. The storms may become better organized and cover more territory as they move through Houston proper and south of I-10 toward the coast late this afternoon.
Here is how one model (the HRRR) forecasts rain chances through the day, ending at 8 PM. A “line” of showers moves through Houston after 2 PM, becoming slightly better organized and heavier south of I-10 and near the coast toward evening. (Weather Bell)
Temperatures should drop from the upper-80s or near 90° back into the 70s behind the showers.
Severe weather via strong wind gusts and hail can’t be entirely ruled out today, but that risk has diminished a bit, and we expect any severe storms would be very isolated and mainly south and east of Houston.
By about 8 PM, most of the storms should be out of the immediate Houston area, but some showers and storms may still be ongoing for places like Lake Jackson or Matagorda. The front will continue to slowly push offshore this evening. However, showers will likely linger into the overnight for those areas south of Houston and Galveston, particularly toward Matagorda, maybe Freeport. Otherwise, it will just be mostly cloudy and breezy overnight. And it will turn much cooler.
Overnight lows tonight should bottom in the lower 60s for many, 50s for some. It will feel much cooler Saturday morning, along with a breeze. (Pivotal Weather)
Overnight lows tonight will bottom out from the lower-60s in much of the area and south of I-10 to the upper-50s to the north. Along with that breeze, it will feel quite cool late tonight and Saturday morning.
Saturday
With a good deal of clouds around much of Saturday morning and an abnormally cold air mass for May dominating the eastern half of the U.S., we’ll likely limp into the mid-70s Saturday afternoon. Those temperatures would be a solid 10 degrees below normal for this time of year. More sun is likely as the day goes on, especially for folks north of I-10.
Along with cool temperatures, expect a pretty steady, gusty offshore breeze. Winds over Galveston Bay will probably peak around 20 to 25 mph or so.
Mother’s Day
Stunning. Sunshine, comfortable humidity, comfortable temperatures. Look for a morning in the 50s to near 60 degrees and an afternoon in the upper-70s to near 80°, along with light winds. Thanks to all the mothers out there for all that they do for the world, and an apology to my mom in New Jersey who will be waking up to 30s on Sunday morning.
