Matt Lanza

Well, we sure hope you got to enjoy the weather yesterday and hopefully today too. Mid-May fronts with cool, comfortable air masses feel like a rare treat. Our morning low of 62° at Bush Airport this morning is the coolest morning this late in the season since May 25, 2017 (60°). The humidity returns later today, tonight, and Saturday, and then rain chances will follow. Our area looks poised to enter into a prolonged unsettled weather pattern for at least least a week or so. Let’s walk through the forecast.

Today

Really, we will just have a nice day ahead today. Look for some sun after these morning clouds in spots dissipate. There will still be a fair number of clouds though this afternoon, and highs will be around 80° or in the low-80s, give or take.

Saturday

Saturday morning will start a bit warmer and a bit more humid than today or Thursday began. Morning lows will be in the 60s, if not 70° or so in most places. Look for a mix of clouds and maybe a bit of sun. If you have the option to choose between weekend days for outdoor plans, we would strongly suggest going with Saturday. While there will be a chance for some showers, mainly west or southwest of Houston, those chances are not especially high or long lasting. It will be warm and turn increasingly humid, with highs in the 80s.

Sunday into Monday

The forecast for Sunday is very challenging. This is mainly due to timing. The last couple days have seen the start time of rain slip in models from Saturday night to Sunday morning to now Sunday afternoon. What we know is that a disturbance is going to cross through our region, and it will likely bring most of us a period or two of showers and thunderstorms on Sunday through Monday.

We may have one area of rain Sunday morning and afternoon move into the area from the west. Rain may then taper off late on Sunday afternoon before another round fires up either Sunday night or Monday morning into afternoon. The exact timing is tricky, but we know most folks will see at least a little rain. You can see from the animation below how precipitable water or how much moisture is available in the atmosphere increases sharply through Sunday morning and afternoon, which will turn a slight rain chance into a fairly healthy one.

Look for highs near 80° or in the low to mid-80s depending on exactly when it rains. Lows will be in the upper-60s to low-70s.

How much rain to expect Sunday and Monday? Always a difficult question to answer, but right now we could see a half-inch to inch on average with some localized places perhaps seeing as much as 2 to 3 inches of rain or even a bit more. Where those bullseyes occur is difficult to predict more than 12-18 hours out, so I won’t speculate on that this morning.

Rest of next week

The rest of next week will feature Texas under the influence of a pattern with lots of moisture around and several disturbances and a dreaded upper low passing across the state. That is a classic spring combination for periods of rain and thunderstorms. Why do I say “dreaded?” Because upper lows are notorious fickle and difficult to forecast. As the saying in meteorology goes “upper low, forecaster’s woe.”

Here’s what we know: The chance of rain will be high each day next week. But, it will not rain all day or perhaps even every day everywhere. More likely we’ll have a day with widespread, heavy thunderstorms separated by a day or two of more isolated or scattered activity. As of today, it appears that Sunday into Monday and later Tuesday into Wednesday have the highest odds of more widespread storms. But I’ve dealt with enough upper lows to tell you that this could easily move around, hence why we’re just blanketing each day next week with a rain chance. We’d expect rain chances to tail off a bit by next weekend.

So how much rain should we expect next week? Well, it’s probably going to vary, widely. Some areas may see an inch or two, while other areas could easily see 4 to 6 inches of rain or even some more by Friday. On average, we would say about 1 to 3 inches should be expected. We don’t think those bigger ticket rainfall amounts will be especially widespread, and we don’t expect major flooding issues right now. But this is the type of forecast we’ll want to watch closely. If necessary, Eric and I will break out the flood scale, but it’s much too soon for that.

Meanwhile, we’ll do our best to try and isolate those heavier periods of rainfall that make travel difficult for you, and if we gain some confidence in those or rain amounts, we’ll also update this weekend.

We’ve had some stellar May weather to close out this week, and today will be no exception. But look for changes this weekend, leading to some unsettled weather next week.

Drought update

So, some good news! The rains of last weekend did a number on drought across Texas. About 20 percent of the state exited drought completely, with about 45 percent remaining there today.

Locally, that change was even more stark. We went from about 45 percent of the region in drought last week to less than 10 percent now in drought.

Overall, last weekend’s rains did not completely end drought concerns, and there are still some localized pockets that didn’t get quite a lot of rain last weekend. But it did put a dent in the drought. The hope is that next week’s unsettled weather will do some more, although as of today it appears that the bulk of next week’s rain may fall in areas that are not in serious need of rain. More on that below.

Today

Look for another winner today with sunshine and some passing high clouds. High temperatures will top off in the mid-80s, with perhaps a couple upper-80s peppered in there too. Humidity remains fairly low, though it will subtly increase later in the day.

Saturday

Tomorrow should still be a fairly decent day. Any outdoor plans should be fine, though I wouldn’t exactly be shocked to see an isolated shower west of the city. We should have some fog in a few spots early, clearing to sun and clouds with morning lows in the 60s again warming into the mid-80s. Humidity will be noticeably higher tomorrow. A southerly breeze will also pick up a bit, so if you’re out on the Gulf or Galveston Bay, be ready for some 20-25 mph wind gusts building as the day goes on.

Mother’s Day

As noted in yesterday’s post, the Sunday forecast is a trickier one. However, while we can’t entirely rule out some more widespread, heavier showers, those seem more likely to stay comfortably north of the Houston area through late afternoon or evening, between Huntsville and Dallas. If you will be traveling to or from Dallas on Sunday, do keep that in mind, particularly in the afternoon or toward evening. But for the majority of our area: Clouds, some sun and just a slight shower chance. There may be some light rain, drizzle, or mist in the morning hours. It will end up warm to hot and humid, with morning lows in the 70s and highs in the mid to upper-80s, along with a steady southeast breeze. I think storm chances may increase a little bit on Sunday evening, but details are still a bit uncertain.

Monday through Wednesday

As we discussed yesterday as well, next week’s forecast is dependent on the orientation of a stalled out cold front near or north of us, as well as the timing of any disturbances rippling by overhead. We know that there will probably be at least scattered thunderstorms next week. We know it may not rain each day and certainly not everywhere each day, but we know that the chances are probably better than 50 percent at times.

While we could see some locally heavy rain in this type of weather pattern, the most likely areas to see that will be north of I-10, because of course. On average, I would expect about a quarter to half-inch of rain south of I-10 Monday through Wednesday, a half-inch to inch or so in the city, and 1 to 3 inches north of the city. But amounts may vary considerably, with some places merely seeing a tenth of an inch or so and others perhaps seeing as much as 4 or 5 inches. Serious flooding is not expected to be a concern.

Late next week

That stalled out front is likely to push offshore late next week, ending rain chances and ushering in offshore winds to allow humidity to drop again for a couple days. Expect lows in the 60s and highs in the 80s, but those mornings will hopefully feel nice. “Hopefully” is carrying a lot of weight in that sentence, but most reliable model data does support lower humidity and slightly cooler temperatures late next week.

Unless it appears that the weather will change significantly this weekend, look for Eric to be back in the saddle for our next post on Monday morning!

We managed the mid-80s yesterday with dew points sitting in the 50s all day, which is pretty comfortable. We get another day or two of that kind of weather before things go back to pre-summer and the details of the forecast get more complicated.

Today and Friday

Look for lots of sunshine and just a few clouds both today and tomorrow. A little low cloud cover or patchy fog is possible tomorrow morning southwest of Houston. We should manage mid-80s both afternoons and upper-50s to mid-60s tomorrow morning, similar to today. Galveston should bottom out near 70° tonight, however. No weather woes, but air quality may be poor. You may have seen the Ozone or Air Quality alerts on your phone or other sites you use for weather info. Having a lot of sunshine, warm temperatures, and light winds tends to help produce ground-level ozone in areas with pollution from heavy traffic and industry. Days like this in spring, summer, and early fall are not uncommon here unfortunately. Take it easy if you have any respiratory sensitivities.

Saturday

Humidity will still be low enough on Saturday morning to allow temperatures to drop perhaps into the low to mid-60s away from the bays and coast. But as Saturday progresses, the humidity will inch upward. Look for highs in the 80s, some sunshine and added clouds, and a very slight shower chance. Saturday night will see temperatures struggle to get below the low-70s, so “pre-summer” will be in full effect.

Mother’s Day

The forecast gets conveniently complicated beginning on Sunday unfortunately. The setup for Sunday and much of next week is going to be contingent on the exact placement of a cold front that is destined to stall out somewhere between the Gulf Coast and Dallas. This will likely lead to at least a couple rounds of thunderstorms, with the first occurring Sunday afternoon. Models still have some disagreements on coverage, intensity, and the exact location of Sunday’s storm chances, however.

The odds of more widespread showers and storms on Mother’s Day are still highest right now north of Houston. But there is little room for error in that current forecast, meaning any shift south will open the door to greater coverage of afternoon storms in and around Houston. The timing may allow for Mother’s Day brunch plans to go off successfully (though there will likely be at least a few showers around late Sunday morning into early afternoon). But those of you with Mother’s Day dinner plans, particularly outside, will want to keep tabs on the forecast.

Look for highs well into the 80s, though any thunderstorms will allow temperatures to briefly cool off.

Next week

As noted above, next week’s forecast will be highly contingent on exactly where that cold front orients and the timing of any disturbances rippling along the front. Expect at least a chance of storms Monday through Wednesday, but trying to hone in on exact details on timing and intensity this far in advance is very difficult. We will know more as we get closer. Look for highs in the 80s to near 90 degrees at times, lows in the 70s.

Another front?

By later next week, the European ensemble, which runs slightly tweaked versions of the European model 51 different times is showing about a 60 to 70 percent chance that the front responsible for next week’s unsettled start will slip through the region and offshore.

You can really only see this reflected in overnight lows, which noticeably drop back on the ensemble (boxed in above) beginning Thursday or Friday morning. It’s worth noting that the GFS model is somewhat less enthusiastic about this possibility. So, there is still some uncertainty here, but if we do see the front clear us next week, look for highs to drop back a few degrees into the low to mid-80s and morning lows to go from the 70s early in the week to mid to upper-60s perhaps, with some risk for slightly cooler. We will see!

With a fine, quiet stretch of weather beginning today for Houston, Eric and I thought it would be a good time to write a bit about the new climate normals released by NOAA on Monday night. When we compare weather to “normal” or “average,” these are the values we are comparing to, so it is useful to understand how they will be changing.

What are they? Every 10 years, NOAA and the National Weather Service, along with other government weather agencies around the globe recalculate what the typical weather has been like in the previous 30 years. Think of it like the Census, but for weather.

Why average 30 years of weather instead of, say, 50 or something? First off, the World Meteorological Organization (WMO), which is essentially the U.N. for meteorological agencies stipulates that member states use a 30 year standard. In general, 30 years is enough data to get you a good snapshot of what the current climate is, rather than a 50 or 100 year average. In other words, when we compare weather to a 30-year normal by saying something like, “Today was 15 degrees warmer than normal,” we’re comparing to the shorter-term climate we’re used to, not the one perhaps our grandparents lived through. And 30 values is generally when statistical averages become more reliable. Some users and industries prefer their “normal” to be calculated over a different timespan, so those calculations will be added to the mix from NOAA as well.

Why do they matter? When dealing with weather and making plans in business or designing buildings or planting crops, you need to have a baseline to anchor yourself to, some kind of “average” weather. Imperfect as they may be, the 30-year normals accomplish that. Having those allows us to explain weather in terms of how typical or atypical it is on a particular day or in a particular month. One thing we all know: Weather changes and can be wild, and “normal” is really just an average of a bunch of various extremes. But we need to have that anchor point to describe weather in a climatological context. I don’t know if this is originally attributable to him, but as Dr. J. Marshall Shepherd, former president of the American Meteorological Society likes to say: “Weather is your mood and climate is your personality.” It’s good to know a local area’s “personality!”

So what has changed? Let’s start big and then go small. Across the U.S., the new set of climatological normals is generally warmer, much warmer. The only areas cooler than the previous set of normals were in the Plains.

Officially, Houston’s annual average temperature (at IAH Bush Airport) rose by 0.7° versus the previous normal. At Hobby Airport that change was 1.0° warmer, and at Galveston it was 1.1° warmer.

The only months that showed cooling relative to the previous set of normals were November and December. Summers have warmed by a bit over a half-degree on average, and late winters have warmed by over 1 degree. Some other notes: Our first day with an “average” high of 90° has moved up to May 29th from June 3rd. Our last day of average highs of 90° or better is September 18th, up from the 14th. So, we’ve added roughly a week more of days with an average high of 90° in 1991-2020 versus 1981-2010. Additionally our hottest daily average maximum temperature (or “peak” of summer) is up to 95.7° compared to 95.0° in the previous set of normals. Not only that, that peak has moved up a bit to August 4-6 versus a longer, flatter peak from August 5-12 previously. I wouldn’t read too much into that last part, but it’s something to note at least.

You’ll also notice that rainfall has increased, thanks in part to average August rainfall being over 1 inch wetter than in the prior normals. This is almost certainly thanks mostly to Hurricane Harvey. Houston now sees rainfall of roughly 2 inches more than we used to each year.

Interestingly, but perhaps not surprisingly to some folks if they live there, Galveston actually saw annual average rainfall decrease in this latest set of normals. In fact, not only does Galveston see less rain now on average, it’s over 3 and a half inches less! This is likely both a function of randomness in the sporadic nature of daily thunderstorms here but also a notable change related to <waves hands> something with respect to the warming water temperatures of the Gulf of Mexico or more frequent ridging in the upper atmosphere over the Southeast. This feels like too big a change to me to be just random chance. In addition, Galveston was substantially warmer, especially during nighttime. Average lows are over 1.5° warmer now than they used to be.

Anyway, hopefully you find this interesting. How we describe weather “relative to normal” will change going forward, so we feel it’s notable to explain to you how that will change. On to the forecast.

Today through Friday

Step outside this morning, folks.

We have temperatures in the 50s inland to low or mid-60s in the city and along the coast. And the humidity has plummeted. Look for plenty of sunshine and highs around 80° or in the low-80s this afternoon. Tomorrow looks just as nice. Expect morning lows in the 50s north and west of Houston and low or mid-60s in the city and along the bay. Galveston should see upper-60s. Another day of sunshine will allow us to get into the mid-80s tomorrow. Friday looks like essentially a carbon copy of Thursday with a few added higher clouds at times.

Saturday and Sunday

Look for onshore flow to kick back in this weekend, driving our dew point temperatures back up to 70° or so, along with highs well into the 80s. Saturday morning will probably see 60s for lows, while Sunday should see 70s in the morning. Along with that, there is at least a chance of a shower or storm Saturday. For Mother’s Day, we expect a slightly better chance of showers, however despite being better, those chances still remain fairly low right now in most of the Houston area. As you go north of Highway 105, the chance for some more robust rain and storms may increase somewhat. We’ll hone in on details more tomorrow and Friday.

Next week

It’s too early to get too into the weeds next week, but with a cold front “in the neighborhood,” suffice to say it will probably be a somewhat unsettled period ahead. More on this for you tomorrow and Friday as well.