In brief: Just a short update to note the formation of the Atlantic season’s first named storm, Arthur, and what it means for Houston today. In short: rains ending, but the next several hours will be windy near the coast.

Hello, Arthur

The Atlantic season’s first named storm, Arthur, has formed less than 100 miles from downtown Houston. Although that may sound concerning, we’re here to tell you it’s really not.

Our biggest concern from this system has been the potential for heavy rainfall, but that risk is now rapidly diminishing. The bulk of the precipitation from Arthur is falling well to the northeast of its center, and most of this is offshore. The scattered showers we are seeing across Houston as of 10 am CT on Wednesday will continue to diminish. We are likely to be rain free from the middle of today through Friday evening. For this reason we are ending our Stage 2 flood alert.

The biggest impact from Arthur is being felt right along the coast. Its sustained winds have been measured at 35 mph, or higher, along Galveston Island, with some gusts up to 50 mph. This has, frankly, exceeded our expectations. Even areas as far inland as Hobby Airport have recorded gusts up to about 30 mph. These winds should start to ease by this afternoon as the center of Arthur nears Galveston and starts to move away. After that we expect calm and sunny, albeit hot, conditions on Thursday and Friday.

We’ll have a full forecast for you, per usual, on Thursday morning.

In brief: Central and southern parts of Houston are seeing rain from an approaching tropical system this morning, which should pass near Galveston Island later today. Winds should be mostly modest, and we expect rains over the Houston region to diminish by late morning or early afternoon.

Tropical update

As of 7 am CT a low pressure system lies just off the coast of Texas, near Matagorda Bay. According to the National Hurricane Center, it is moving to the northeast at about 7 mph and should continue to track more or less along the upper Texas coast today. This will bring its rather poorly defined center near Galveston Island sometime today, likely during the early afternoon hours. Although there remains a chance this system becomes a tropical depression or storm, whether it does so largely does not matter for the greater Houston region today as it passes by. The system’s effects are now essentially baked in.

Wednesday

Most of the Houston region saw a quiet night, but areas southeast of Houston, including Pearland, Clear Lake, and League City, picked up 2 to 3 inches of rainfall. Additional showers are now spreading into the Houston metro area this morning as the tropical system nears our region. These showers are likely to persist through the morning hours before lesser coverage this afternoon. Additional accumulations of 1 to 2 inches are possible, although most locations will see less than this. The impactful rains from this system are falling to the north and east of its center, so as the center moves near Galveston Island these rains should move on to east Texas and southern Louisiana.

In terms of winds, coastal areas including Galveston Island could see winds pick up to 15 to 20 mph today as the center passes nearby, with some gusts up to 30 mph. Water levels may rise 1 to 3 feet above tide levels, so some minor coastal flooding is possible.

High temperatures today will be dependent upon rain coverage in your location, but should range between 85 and 90 degrees.

Thursday and Friday

These are likely to be partly to mostly sunny days with rain chances of 10 percent or less, allowing the soaked Houston region a good opportunity to dry out. Each day should have high temperatures in the lower 90s with a good deal of humidity. Nighttime lows will be very muggy, with air temperatures likely falling only to around 80 degrees.

Saturday and Sunday

A decent chance of rain, perhaps 40 or 50 percent, returns on Friday night or Saturday, but the day should still be partly sunny with highs in the vicinity of 90 degrees. I don’t have great confidence yet in Saturday’s rains, but these showers should be of the passing variety rather than something that persists for hours on end. Sunday looks to be mostly sunny with significantly lower rain chances. Expect highs in the lower 90s.

Next week

Most of next week looks warm and sunny, with highs in the low- to mid-90s. Temperatures have been cooler this week with the widespread showers. That likely will change next week as we experience more summer-like weather in Houston.

In brief: In this afternoon’s update we discuss the region’s diminishing heavy rainfall threat even though a Tropical Storm is likely for form off the Texas coast on Wednesday. We also go over what you can expect from that.

The Woodlands had a day

Rather than closer to the coast, the most persistent band of storms lined up along northern Harris and southern Montgomery counties on Tuesday. Some gauges along Spring Creek, including areas near Tomball and The Woodlands, picked up as much as 6 inches of rain in short order.

When we speak about highly variable rainfall totals with a few bullseyes, this is exactly what we mean. Much of Harris County received 0.5 inch or less on Thursday, but for a relatively small part of our region there were very heavy and persistent rains leading to significant street flooding. This is the textbook definition of a Stage 2 flood event in Houston. It’s pretty brutal if you’re sitting right under it, but for most of the rest of the metro area, things are just fine. Anyway, as of 4:30 pm CT the radar is largely quiet across the region.

Speaking of that Stage 2 flood alert, we are going to hold on to that overnight out of an abundance of caution. We’ll revisit things on Wednesday morning.

Tuesday night

Although some sporadic showers are possible during the overnight hours, the radar should remain fairly quiet into early Wednesday morning. So go about your business as usual.

Wednesday

Some time on Wednesday a low pressure system may well become a tropical storm as it traverses across the Western Gulf, near the Texas coast. Its center may briefly touch land from time to time, but overall the system should continue to track to the northeast. By Wednesday evening it should be inland for good, somewhere near Beaumont or Lake Charles.

Houston’s coastal areas (including Galveston Island) may see tropical storm force wind gusts on Wednesday morning, and these will probably peak around sunrise. In terms of storm surge, expect water levels to be 1 to 3 feet above normal tide levels. So this could cause some minor flooding for low-lying coastal areas.

So what about rains? Yes, we’re going to see the continued possibility of showers and thunderstorms, and the threat of heavy rainfall looms for tomorrow. But my expectations for Wednesday is that most of Houston probably sees 0 to 1 inch of rain, with some bullseyes of 3 inches possible for a few isolated areas, most likely near the coast. Needless to say this should be pretty manageable.

The rest of the week

We’ll have more detail tomorrow, but we are now reasonably confident that Thursday and Friday will be mostly sunny days with highs in the low 90s and fairly low rain chances (if not zero). I’m not particularly confident about Saturday’s forecast as there’s a chance of some storms back-dooring in from the northeast (think 1 inch of rain, or less). Sunday looks mostly sunny and rain free.

In brief: We expect widespread showers and thunderstorms today, particularly south of I-10, where flash flooding is possible. Our current thinking is that a tropical disturbance expected to track across the Western Gulf on Wednesday will remain far enough offshore to spare Houston from significant flooding, but we’re going to watch things closely.

Behold, the tropics

As of this morning a low pressure system located over South Texas is starting to move toward the Gulf. On Wednesday it should move to the northeast, just off the Texas coast, toward Louisiana. At this time it may have a brief period during which it can spin up into a tropical depression, or possibly a named storm (it would be called Arthur). The National Hurricane predicts there is a 60 percent chance this occurs. Although certainly there would be a lot of noise around a tropical storm forming in the Gulf so close to Texas, we’re here to tell you the impacts from this system are going to be similar regardless of its development in the coming days.

And there’s some good news in the forecast. Remember how we’ve been talking about the boom or bust potential later this week, on Wednesday and Thursday, due to heavy rains from this tropical system? As of Tuesday morning we are leaning toward bust. Put another way, after today and this evening, our rain chances will probably trend down somewhat. And we think the likelihood of very heavy rainfall (i.e. bullseyes of 10 inches or above on Wednesday and Thursday) in the Houston metro area is low. It’s not zero yet, but things are trending in the right direction. There will be some winds and tides to contend with, but nothing too significant. More on that below.

Tuesday

In terms of heavy rainfall, conditions will be most favorable today across the Houston region with rich tropical moisture spreading into the area. There is a thick band of heavy rainfall offshore the Texas coast this morning, spreading all the way from Corpus Christi to Port Arthur. The key word there is offshore. Some of this activity is spreading inland this morning, and we expect rains to move into the Houston area today. Due to the tropical nature of this airmass, rainfall rates could be quite high, quickly leading to street flooding (and hence, our Stage 2 flood alert).

Rain accumulations today should be highest along and to the south of Interstate 10. In these locations 2 to 4 inches of rain will be possible, with some isolated areas of 6 inches possible. Further north totals should be less. Due to the rain-cooled air mass temperatures today for most locations should be in the 80s, with lower 80s likely near the coast. Rain chances should slacken somewhat overnight, but there will still be pockets of activity.

Wednesday

The aforementioned tropical system should pass closest to Houston on Wednesday. At this time we think it will track southeast of our region, remaining off the coast. In this case it should keep the heaviest rains offshore. The major risk at this time is if the system tracks more to the north, and moves inland into the Upper Texas coast. This would mean more rain over the Houston metro area. To be clear, we don’t think this will happen, but we are watching for this possibility and will of course keep you informed.

Anyway, our best-guess forecast at this time for Wednesday is for about a 60 percent chance of rain showers, with better chances and higher accumulations closer to the coast. For now rain totals look fairly manageable, with 1 to 2 inches, but again this would change if the tropical system took a more northerly route.

We are also likely to see some coastal wind gusts of about 30 mph, starting early Wednesday morning. I’m not sure how far inland these will extend, but it’s possible they could reach areas such as Pearland or League City. (Again this is dependent on the tropical system’s track). Water levels will also be 1 to 3 feet above normal tide levels, so there could be some minor coastal flooding. High temperatures on Wednesday should be in the upper 80s.

Thursday and Friday

At this time we expect rain chances to step back on Thursday and Friday, likely back into the 40 percent range. These likely would be more of your typical summertime showers and thunderstorms rather than anything too serious in terms of flooding potential. Highs will likely reach the lower 90s with more sunshine.

Saturday, Sunday, and beyond

The weekend looks to be partly to mostly sunny, with high temperatures in the lower 90s. There probably is about a 40 percent chance of rain on Saturday (hard to have too much confidence one way or other here), with lower chances on Sunday. Most of next week will probably see highs in the lower 90s, with the potential for scattered showers but fairly low chances overall. Basically it should be a return to normal programming for June in Houston.