In brief: In today’s post we discuss our rapidly rising dewpoints, and how a weak front will only modestly knock them down. Our rain chances this week have shifted a bit, with Thursday and Friday now the most likely days. The latter half of this weekend looks pretty darn warm.

Dewpoint recovery

The main reason why the weather felt so comfortable this past weekend was an uncharacteristically sharp drop in dewpoints for early May. Technically, the dewpoint is the temperature to which air must be cooled for it to become saturated with moisture. But more generally they’re easy to understand this way: Dewpoints in the 40s and below mean the air feels dry and refreshing. The 50s are comfortable, whereas the 60s start to feel somewhat humid, and 70s and above are rather muggy. I don’t even want to talk about dewpoints in the 80s, but in a month or two we’re probably going to have to.

This weekend dewpoints in Houston reached the 40s on Saturday and Sunday before rising into the 50s on Monday. All of this felt rather comfortable. But this morning dewpoints have recovered to about 70 degrees for most of the region, and by Wednesday they’ll be in the mid-70s. So yeah, it’s going to feel humid for the next couple of days before a weak front brings some very slight relief.

Tuesday

In addition to rising humidity, temperatures today will also be climbing. How warm will depend on how much clouds break up this afternoon. For most of us, temperatures will range from the low- to mid-80s, but sunnier spots could rise into the upper-80s. It’s also going to be breezy, with gusty winds from the south as high as 25 mph later this morning. Rain chances are less than 10 percent. Clouds return this evening, with lows only dropping into the mid-70s.

Wednesday and Thursday

Wednesday will be another humid day, with highs likely reaching the mid- to upper-80s. With increasing moisture levels we are going to see some scattered showers, but I don’t think it will be anything too serious. A cold front will approach the region later on Wednesday, but the overall trend in the models has been slower. Therefore, although some storms may be possible Wednesday night, it now appears as though this activity will be delayed into Thursday morning when this front sags into Houston. So, bottom line, it looks like the best chance for rain and potentially storms will come on Thursday in association with the front. In terms of accumulations most of us will probably get 1 inch or less, so flooding does not appear to be a major concern. But we’re going to keep an eye on things because a slow moving front and ample moisture can always cause some problems. Highs Thursday should top out in the upper 70s with lows Thursday night should be a little cooler, perhaps in the 60s.

Friday

A healthy chance of showers and possibly thunderstorms lingers on Friday, with mostly cloudy skies and highs near 80 degrees. The air will be slightly less humid (i.e. dewpoints in the 60s).

Saturday and Sunday

I’m starting to have a little more confidence in the weekend forecast, but don’t write things down in ink just yet. Saturday should be mostly sunny, with highs in the low- to mid-80s. So at this time I’m cautiously optimistic that things look good-to-go for most outdoor activities. Sunday looks pretty hot, with highs inching up toward 90 degrees, depending on the extent of sunshine we see. There will be at least a slight chance of showers and thunderstorms on Sunday.

Next week

It’s possible that a weak front makes it through Houston on Monday or so to bring us some cooler air, or maybe not. Now that we’re into May, cold fronts become a lot more uncertain this far south. So we’ll have to wait and see.

In brief: After stunning weather across Houston this weekend, we return abruptly to reality this week with rising humidity levels and warmer weather. Beginning on Wednesday we’ll also see rising rain chances that may linger into next weekend.

Peak weather

This weekend’s weather was not perfect for everyone, or every activity. For a beach day, you might want it a little warmer. For long-duration running, maybe you’d want things a little colder. But for being outside, for working in the yard, taking a walk, or watching the sunset—this weekend was perfect. We had clear skies, low humidity, cool mornings and pleasant days, and after Saturday morning modest winds. With these four conditions, Houston hit the quadfecta. Not only that, the weekend came after some super helpful rainfall that knocked most of the region out of a months-long drought. It felt good.

I am confident in saying this will be Houston’s nicest weekend for at least the next five months, and probably longer. Given that both Saturday and Sunday had exceptional weather, it was probably was the nicest wall-to-wall weekend we will have all year. I hope you found some time to spend outside.

Monday

We are going to have one more sunny day before our skies turn mostly cloudy for awhile. Winds have already shifted to come from the southeast, and this morning’s light breeze will pick up this afternoon to come from the southeast, gusting up to 25 mph. Expect sunny skies with a high temperature of around 80 degrees, or perhaps a touch warmer. Humidity will steadily rise throughout the day and accordingly our lows tonight will only drop to around 70 degrees in Houston, with slightly cooler conditions for outlying areas.

Tuesday

A warmer and more humid day with high temperatures generally in the mid-80s. Skies will turn partly to mostly cloudy. The onshore flow will become even a little stronger, with southerly wind gusts up to 30 mph. As a result of this flow the moisture levels in our atmosphere will increase, but I think any rain showers will hold off until at least Tuesday night or Wednesday. Lows on Tuesday night will only fall into the mid-70s.

Wednesday

A cool front will approach the area from the north, and if you read ‘Tuesday’ section of today’s post you’ll know that with all the southerly winds we’ve been pumping up the available moisture for showers and thunderstorms. The front will disturb the atmosphere enough such that there is a low-end chance for some severe weather later on Wednesday, especially for areas north of Interstate 10. So there’s the possibility of some showers and storms on Wednesday afternoon and evening, and then the front itself will probably sag into the region Wednesday night. Bottom line: there’s a fair bit of uncertainty in rain amounts and temperatures. For now I’ll predict highs in the mid-80s on Wednesday, with overnight lows dropping to around 70.

Thursday and Friday

Our weather to end the week is going to depend where you live (i.e. further from the coast, a better chance of lower temperatures and slightly lower humidity). Basically I would expect highs in the vicinity of 80 degrees and lows in the 60s. Both of these days will also have a heathy chance of rain, perhaps 50 percent each day. Overall accumulations through Friday will probably be on the order of 1 inch for most of us, but there will be some wide variations. Anyway, if you have outdoor plans from Wednesday through Friday some caution is advised, as a lot of questions remain.

Saturday and Sunday

Rain chances are not going away this weekend, but whether they’re 20 percent for both days, or 50 percent, I just cannot say with this unsettled pattern. I think we’ll see a mix of clouds and sunshine. Highs will likely be in the vicinity of the low-80s with lows in the 60s or perhaps lower 70s. Stay tuned for a better weekend forecast, because we’re just not there yet.

Next week

It’s possible that another weak front arrives early next week, and this should help keep our temperatures in the lower 80s, with maybe a cooler night or two. Daily rain chances do start to look lower after next Monday or so with the potential for more sunshine. We’ll see!

In brief: The current storms across the region are behaving more or less as expected, and much of the Houston region is getting a good soaking with no major problems. We see one more wave of storms this afternoon before the front moves offshore.

Houston weather status: It’s raining. And it will continue to do so for several more hours.

We have seen a couple of waves of showers and thunderstorms today, with a pulsing up of intensity followed by a break. This has brought some healthy rain totals, with up to 4 inches over the last 24 hours northwest of Houston, near locations such as Cypress. Most other areas have picked up 1 to 3 inches. Pretty much all of the region’s major bayous and waterways remain within banks, so the issue has primarily been one of brief street flooding.

Based upon radar trends and our most recent high-resolution modeling, it appears likely that one final wave will push through the metro area between 3 and 5 pm, from west to east. This could bring an additional 1 to 2 inches of rainfall for some locations, and we cannot rule out some severe impacts such as damaging winds and possibly hail. As this wave should cross our region during the evening commute, please take a little extra care. After this, from approximately 5 to 9 pm, we likely will see some additional light to moderate showers before the mess moves off to our east.

That will be the end of the rain, but it will be replaced by gusty winds from the north-northeast, up to 30 mph in Houston, and perhaps a bit higher along the coast. These gusts should start to subside on Saturday morning, before dying off during the afternoon hours. The weekend still looks splendid and sunny, with chilly mornings and pleasant afternoons in the 70s. Enjoy!

In brief: Periods of heavy rain will track through Houston throughout the day today, especially along and north of I-10. Additionally, some strong to severe storms are possible this afternoon across the southern 2/3 of the area. Street flooding is a good bet today. Rain ends this evening with gusty winds overnight. But a stellar weekend awaits.

Today

So far this morning, heavy rainfall has been limited to the northern half of the Houston metro, this after some strong storms overnight brought numerous hail reports from Sugar Land through Missouri City and Pearland.

Areas between Cypress and Spring have seen 2 to 3 inches of rain since yesterday. The area that saw hail also received close to 1.5 inches of rain in many spots. Rain continues to jet along and north of Highway 59/I-69 in and west of Houston this morning and north of I-10 east of Houston. That’s going to be the general pattern for most of the day, where those areas see fairly persistent rainfall.

Severe weather risk

However, as we get into the late morning and afternoon hours, there will likely be at least a couple of more ambitious clusters of thunderstorms that develop south of those areas. This would be primarily along and south of I-10 across the Houston metro all the way down to the coast. Not to say we could not see a couple of these find their way north of the I-10 corridor into Liberty, Waller, or northern Harris County, but the severe weather focus today will be mostly south of there. Again, I-10 is not a magical barrier; it’s just a nice, easy demarcation line that most readers generally know.

As these storms wiggle through, any of them will be capable of producing 40 to 50 mph wind gusts, some large hail, and frequent lightning. As you get closer to, say, Freeport, Lake Jackson, Matagorda Bay, or as far south as Corpus Christi, there is also a little bit of “spin” in the atmosphere that could yield a storm that produces a tornado, so just be aware of that. The entire southern two-thirds of the area is in a marginal risk (level 1/5) primarily due to the hail risk, but also due to the wind and very isolated tornado risk.

Flooding risks

In terms of how much additional rain we see, the entire area away from the coast is under a Flood Watch from the National Weather Service in Houston, a slight risk (level 2/4) for excessive rainfall from the NWS’s Weather Prediction Center, and a Stage 1 Flood Alert here on Space City Weather.

What does that tell you? Street flooding is probably a good bet today. This is a good day to be weather aware if you have errands to run or appointments to tend to. Give yourself extra time to get where you need to go. This will be especially true in the second half of the day as the ground will be saturated, making some street flooding more likely.

How much additional rain should we expect? It will vary, but likely another 1 to 4 inches of rain through the duration of the event where it’s currently raining (as of 5:30 AM). South of those areas should see anywhere from a half-inch to 2 inches of rain depending on exactly how this afternoon’s thunderstorms align. The latest HRRR model’s depiction of additional rainfall through this evening is shown below. Don’t focus on specifics here, but you can see the general pattern of how things should flow.

The good news is that rain should be out of here tonight, so expect the rain to end from west to east from about 8 PM through 1 AM or so. Early evening plans will be dicey, but late evening plans may be ok. Just don’t drive through any residual flooded roads!

Eric will have another update on today’s weather situation by the afternoon.

Gusty winds

One last note: As the rain begins to wind down, and the front pushes through with the disturbance kind of wound up, we are going to see non-thunderstorm winds increase. This should be especially true near the coast and in the southern half of the area. Inland wind gusts should be on the order of 20 to 30 mph beginning after 6 PM. Some locally higher gusts are possible. Coastal wind gusts will be more like 35 to 45 mph, and gale warnings are posted for the bays and Gulf.

Winds should be at their gustiest from about midnight through 7 AM Saturday. Then, you’ll see them gradually subside through the day tomorrow.

Weekend

Other than the wind in the morning, tomorrow looks glorious with low humidity, sunshine, and highs in the mid-70s. Overnight lows will be in the 50s. Sunday looks just as nice or better with more sun and highs in the upper 70s to near 80 degrees. Enjoy the early May, comfortable weekend spring fling!

Next week

Looking ahead, temperatures do warm up a good bit, back close to 90 degrees by the time we get to Tuesday or Wednesday. Believe it or not, another May cold front may be in the cards for later next week. Details forthcoming on that, but additional rain and storm chances may be in the cards around then as well.