In brief: Good afternoon. Matt and I have seen enough data to put a Stage 1 flood alert into place beginning today, and to remain place until further notice. In truth we can probably expire it Wednesday or Thursday, but we want to see how the pattern evolves before setting an end date.
Essentially, with high pressure having departed, the region now lies open to a series of disturbances that will bring rounds of showers into the region for much of this week. The first of these can be expected later this afternoon and into the early evening, and the next one after that by either late morning on Tuesday or into the early afternoon. Then we will continue to see the potential for additional rounds of showers, thunderstorms, and potentially severe weather (perhaps hail) for a couple of more days.
The threat level here is not super high. But with this Stage 1 flood alert we want to call attention to the possibility of intermittent heavy rainfall that may briefly back up streets and lead to some mobility issues. Not everywhere is going to see rain every day, or as every round passes through. However, with each passing system there are likely to be some pockets of heavier rain, and we want you to take a little extra time and care in such storms.
We will, of course, have a comprehensive update on all of this Tuesday morning.
In brief: Temperatures in the Houston region soared into the upper 90s this weekend, but with the departure of high pressure our atmosphere has now been cracked open to storm activity. There will be a healthy chance of showers and thunderstorms all week, which will help keep a lid on temperatures.
Weekend heat
The city of Houston did not set heat records this weekend, but we came close and the temperatures outside offered a preview of what we can expect later this summer. The record highs for both Saturday and Sunday were 99 degrees (set in 1903 and 1980, respectively), and we hit 97 degrees on Saturday and 98 on Sunday at Bush Intercontinental Airport. Combined with humidity and warm nights, it felt like deep August out there. Alas the climatological ‘peak’ of summer heating in Houston is still about two months from today. Now, at least, a reprieve.
Radar reflectivity across Houston at 6:24 am CT. Click to enlarge. (RadarScope)
Monday
A line of storms is advancing upon the Houston region from the north, and as of sunrise it is moving into the central metro area. These storms are relatively slow-moving, and will work their way through the city and down to the coast by around noon. We are not seeing too much in the way of severe weather with these thunderstorms, but they could certainly produce some ponding on roadways and cause some brief street flooding issues.
Skies should clear out later this morning, and this should allow high temperatures this afternoon to push into the low- to mid-90s. With this daytime heating we may, in turn, see the development of some additional showers and thunderstorms this afternoon or early evening in central Houston. Lows tonight will only drop into the upper 70s.
Tuesday, Wednesday, and Thursday
This period should see unsettled weather. In the broader picture, with high pressure having departed, a series of disturbances will produce healthy rain chances each day. Again, we cannot entirely rule out the possibility of some damaging winds or other severe weather, but the primary threat during this period will be the potential for heavy rainfall.
Overall, I think this will be manageable, with most of the area picking up between 1 and 3 inches between now and Thursday. But this is Houston, we’ve reached summer, and there is always the potential for heavy rainfall that briefly backs up streets. This is a function of a) living near a very warm body of water in the Gulf of Mexico and b) living in a relatively flat city where it takes time for tropical rains to drain. But I don’t expect it to rain all the time, and some locations probably will not see rain some days.
Daily high temperatures will be dependent up cloud cover, and when and how much it rains during the afternoon hours when it typically is hottest outside. But each of these three days should see highs in the vicinity of 90 degrees, with some locations a bit above, and others a bit below. Although daytime temperatures will be a bit cooler, humidity will be plenty high, and you know those nights will be warm and muggy.
NOAA rain accumulation forecast for now through Friday. (Weather Bell)
Friday
Skies should turn a bit more sunny as we get toward the weekend. Expect highs in the lower 90s. Rain chances will still be decent however, at least 50 percent for much of the area.
Saturday and Sunday
Daily rain chances remain on the menu this weekend, probably about 50 percent each day. Overall accumulations should be quite a bit lower this weekend, i.e. I think the potential for street flooding will diminish. Probably. Expect highs generally in the lower 90s, with partly sunny skies. Nights will only fall into the upper 70s.
Next week
This overall trend should persist into next weekend; that is temperatures probably will remain the lower 90s with a decent chance of showers each day. If you’re bummed about the rain, I get it. But this is the kind of pattern that really helps set our region up nicely for the typically hot and dry patterns we can get locked into in July, or August, or both.
In brief: In today’s post we discuss the best tool we have for determining “heat” during the summer time months, something called the wet bulb globe temperature. And we’re going to need this tool for the weekend, when air temperatures should spike into the upper 90s. Next week looks significantly cooler and wetter.
Let’s talk about heat, and how we measure it
We are getting toward the spiky bit of summer—although to be clear, summer does not typically peak in Houston until late July and the first part of August—so I want to talk about heat. Air temperature is one factor in how “hot” it feels outside, certainly the most important. But other factors such as dewpoints (which indicate humidity, and are guaranteed to be high this time of year), winds, cloud cover, and Sun angle also matter as well. The most comprehensive measurement of all these factors is something known as “wet bulb globe temperature.”
That’s a funky sounding, non-intuitive name, but basically it means the heat stress you will feel when stepping outside into the sunshine at any given point in time. Matt and I feel as though this is the best tool for a “quick glance” at how truly hot our weather will be in the next several days, and when care should be taken for extreme conditions. So in the coming weeks and months we will occasionally be sharing the graphic below to indicate how hot the coming days will be. As you can see, our region’s heat will crescendo this weekend before backing down early next week.
Wet bulb globe temperature forecast for Houston for the coming week. (Weather Bell)
Thursday
Today won’t be super hot because we’ve got a chance for some lingering showers (perhaps 20 percent), and high pressure has yet to fully assert itself over the region. So expect high temperatures generally in the lower 90s, to go along with mostly sunny skies later today. Expect light winds, from the southwest, at 5 to 10 mph. Lows tonight will drop into the upper 70s.
Friday
This will be another day of temperatures in the low 90s with mostly sunny skies. We should also start to see the onset of hazier skies, as Saharan dust moves into the area after riding the trade winds all the way across the Atlantic Ocean. This will be a nuisance for people sensitive to air quality, but for most of us it will just dim the brilliance of sky a bit, and make our sunsets more reddish. Expect another warm night Friday.
High temperature forecast for Sunday. (Weather Bell)
Saturday and Sunday
Temperatures will peak this weekend, with highs in the mid-90s on Saturday for most locations, and pushing well into the upper 90s on Sunday. It remains to be seen whether the haze shaves a degree or two off the top end of these highs, but all the same it’s going to be stinging hot outside. We are also near the point of the year when the Sun reaches the highest point in the sky, so please protect your skin if you’re going to be outside between about 10 am and 4 pm.
Next week
High pressure starts to retreat next week, opening us up to a more unsettled pattern. By Tuesday or so this should bring us cloudy skies and cooler weather (highs in the upper 80s are possible). Rain chances will also be on the upswing Tuesday, with healthy chances daily for showers and thunderstorms. It’s too early to have much confidence in rain totals, but I expect much of the region to get a good soaking, with the usual threat of some street flooding with summertime rains. If you have outdoor plans during the afternoons and evenings next week, you’ll definitely want to have some back-up plans in mind. Beyond this, we can’t offer much specific in terms of which days are most likely to see rain.
In brief: A decaying front will provide the spark for some shower and thunderstorm chances today. Not everyone will see rain for sure, but a few locations may see heavy showers. After today we start drying out and heating up, with the weekend looking especially warm. Some locations will approach 100 degrees.
Wednesday
A weak front will stall out north of the Houston metro area today, but it should get close enough to perturb our atmosphere enough to make things interesting in terms of showers and thunderstorms. Later this morning, and during the afternoon hours, we will see boundaries setting up across the region that may collide with the sea breeze to produce some activity. Overall rain chances are probably on the order of 40 percent—so for many us we may see dark skies and possibly lightning nearby, but no rain. However, I do think there will be some pockets of the Houston area (more likely north of Interstate 10, but it really could be anywhere) that pick up a quick 1 to 3 inches of rain. We may also see some damaging winds, but for the most part I think the predominant threat is heavy rain.
It is far from guaranteed that you will see storms today, but it is possibility. (NOAA)
Mostly cloudy skies and rain-cooled air should help keep a lid on temperatures this afternoon. Most of us will probably reach around 90 degrees, give or take a bit. Humidity will remain high, of course. Winds will generally be about 10 mph from the south, but stronger gusts will be possible within thunderstorms. Lows tonight will drop into the upper 70s.
Thursday and Friday
These should be a pair of mostly sunny days, with high temperatures in the low 90s. So, fairly typical as early June weather goes. However, at some point on Thursday or Thursday night, we should start to see increasing levels of haze (due to Saharan dust) over the area. This is mostly harmless, and actually benefits our soils. But for people who have sensitivity in breathing, it is certainly unwelcome. Another change on Friday is that we should also see more pronounced winds from the south, with gusts as high as 20 or 25 mph.
High temperature forecast for Sunday. (Weather Bell)
Saturday and Sunday
There’s no way to sugar coat this: The weekend looks hot as high pressure sets up over the area. Saturday will see highs in the mid-90s, and Sunday should jump up into the upper-90s. A few inland locations may touch 100 degrees. Hazy conditions should linger into the weekend. Nights will be sultry. A few showers may develop along the sea breeze both afternoons, but I’d peg the chances at somewhere near 10 percent. So, unlikely.
Next week
Some relief is at hand, however. The ridge of high pressure should retreat next week, opening us up to daily shower and thunderstorm chances. Accordingly I think we’re looking at highs of around 90 degrees next week, with partly to mostly cloudy skies, and perhaps an accumulation of 1 to 2 inches of rain. That’s a very rough guess, of course.
