Matt Lanza

Thursday saw the beginning of the transition from our wet pattern this week to a much drier one as we head into the weekend. Recent rain totals have varied widely across the area. Let’s quickly just look at rain totals for the last 7 days.

Since last week, we’ve seen as much as 6 and a half inches of rain between the Galleria and Beltway, with the highest observed total I can find being 6.68″ at Buffalo Bayou and San Felipe. New Territory out by Sugar Land has seen over 5 inches over the last week, as have parts of Pasadena and Cypress as well. On the flip side, Katy, Galveston, and League City have all registered maybe a half-inch or less. So that map above may not be entirely accurate for your specific backyard. That’s the challenge of Southeast Texas rain. Literally one side of the street can see rain while the other side is dry. Speaking of rain, it will be a rare commodity over the next 4 to 5 days or so, as summer revs back up.

Today through Sunday

The chance of rain between now and Sunday is certainly not zero, but it’s probably as close to that as you can get this time of year in Southeast Texas. Expect mostly sunny skies the next several days. Here’s the good news, sort of: While it will be hot this weekend with highs well into the mid, if not upper-90s, it will not be exceptionally humid. That said, it will still be hot enough for heat index values to easily top off at or just above 105° each afternoon, which is hot enough to take it easy and drink plenty of water.

Morning lows will be in the 70s. There should be a little breeze each day, but nothing too refreshing or intrusive.

One thing to keep in mind this weekend: As Tropical Storm Grace approaches Mexico, well to our south, some rough surf and strong rip currents should make it to the coast here in Texas. Please use caution if you’ll be swimming in the Gulf. Also, there could be some minor tidal flooding with wave runup, particularly near Surfside Beach or Crystal Beach. Nothing too serious, but we don’t want you to be caught off guard by that.

Monday and Tuesday

Look for a gradual increase in onshore flow. Coupled with a rather hot air mass still overhead, this should yield slightly more unpleasant heat index values, with some areas perhaps sneaking up closer to 110° or so in the afternoon, especially after the sea breeze comes through. That said, the return of onshore flow should mean the return of at least some minor rain chances. Look for a couple showers or storms in the area on Monday and Tuesday afternoons. But most of us will probably continue dry.

Later next week

The pattern should return to one that’s at least slightly cooler with more typical rain chances for this time of year. Still, expect generally mid-90s each day.

Tropics

Tropical Storm Grace is in the Bay of Campeche this morning, and it will arrive in Mexico tonight as a hurricane (Editor’s note: It strengthened back into a hurricane just after this post was published).

Grace may actually cross Mexico and wind up in the Pacific Ocean, becoming a new storm next week. Grace would have to maintain organization all the way across to keep the name Grace on the other side. That probably won’t happen, so it’s more likely that Grace will dissipate and reform as a new system in the Pacific. Their next name on the list is Marty. The last storm to fully maintain itself from the Atlantic to the Pacific was Hurricane Otto in 2016. Last season’s Hurricane Nana crossed Belize, dissipated, and reformed in the Pacific as Tropical Storm Julio.

Anyone with friends or family or travel plans in New England will want to keep an eye on Tropical Storm Henri this weekend. Henri has failed to get really organized as of yet, which is good news, as a stronger storm likely would make it farther west before turning. Still, it’s expected to become a hurricane this weekend, and it is now likely to make landfall in New England or perhaps Long Island as a hurricane.

As a result of this, hurricane and tropical storm watches are in effect from just east of New York City to just south of Boston. There are still some uncertainties as to exactly how strong Henri will be and where it will make landfall, but given how wet the Northeast has been this summer, flooding could be a significant problem where it does track.

While 3 to 5 inches of rain sounds almost laughable to us in Houston, given the terrain of New England that can cause trouble up there.

Lastly, while we expect a quiet Gulf over the next week, there are at least some hints that tropical moisture or a disturbance could sneak into the western Gulf late next weekend or the week of the 30th. While there’s not a ton of support for anything specific or particularly strong, I think that is the next period we’ll be keeping tabs on in the days ahead. Nothing we need to worry about at this juncture though.

Not a ton of storms yesterday, but those that did occur were noisy, and one even produced a tornado in northwest Harris County.

Tornadoes aren’t exactly commonplace in summertime storms around here, and nothing about yesterday was especially remarkable from a severe weather risk standpoint. This tornado may have been more like a “landspout” rather than a classic tornado. But Thursday’s event serves as a good example of how a tornado can occur if the right conditions come together, even briefly. Sometimes these things just happen. Moving on, we have another pair of fairly typical summertime days before things get perhaps a little more unsettled later this weekend.

Friday & Saturday

Both today and tomorrow look fairly similar for the most part with sunshine, some clouds, and hot, humid weather. Look for highs in the mid-90s, possibly upper-90s. Lows will be generally in the 70s to near 80 degrees. Rain chances are in the general 20 to 40 percent range both days, with Friday perhaps seeing higher risks south and Saturday seeing higher risks north.

Sunday

I think I’ve used the word “front” this summer more times than in any previous summer in my almost 10 years in Houston. Yet another “cool” front will approach the region Sunday. As per usual in August, it won’t clear our area, and we almost certainly won’t see less humidity. But it will likely be enough to help increase our shower & storm chances closer to 50 percent or even a bit higher. So, of course, that means some neighborhoods likely won’t see rain this weekend, but others could get doused with a couple inches in a short time.

With clouds and showers more prevalent regionally on Sunday, we will probably see slightly cooler temperatures, and highs should top off in the low to mid-90s with morning lows in the 70s.

Early next week

I think Monday will just be a logical extension of Sunday’s weather with slightly higher than usual storm coverage during the day and temperatures perhaps held back a degree or two due to clouds. By Tuesday or Wednesday, the pattern should gradual resolve back to more typical August with daily, sea breeze driven showers and storms and highs generally in the mid-90s and lows in the 70s.

Tropics

Fred has struggled a good bit since yesterday, barely holding on at times. But Fred’s not quite dead yet we don’t think, and it looks as though it will at least try to regain a little momentum as it lifts north into the Eastern Gulf. It is not a concern for Texas at this time.

Fred should still struggle, even if it better organizes some, as the system deals with wind shear that is not expected to relent much between now and landfall. Look for a moderate tropical storm, probably at worst. Rainfall of between 4 and 10 inches is possible along and east of where Fred tracks, meaning a good bit of Florida will get a good bit of rain. Georgia and Alabama may also see some fairly healthy rain.

Behind Fred, the system called “Invest 95L” will continue along west-northwest, with high odds of developing into a tropical system by the time it gets to the northern Caribbean islands. It should face similar challenges to Fred, so I’d only expect slow, gradual development at this time. We should continue to monitor Invest 95L’s progress, but at this point, our best models continue to say this is unlikely to be a western Gulf threat. Another area of storms may emerge off Africa this weekend that will have some slight odds to slowly develop also.

There was nothing inherently special about yesterday. We had some sun, some clouds, some haze from passing wildfire smoke. But we only managed to hit 89° officially at Bush Airport with dew point temperatures in the 60s for the majority of the day.

For August, that is almost as good as it gets around here. We are going to see changes this weekend, and a return to more typical summer weather should be expected over the next few days.

Friday

Today looks like a bit of a transition day. We bring back some humidity. We bring back some temperatures. And we bring back at least a smattering of hit or miss showers, downpours, or thunderstorms. Not everyone will get wet today, but about 30 to 40 percent of the region should see at least something. The highest odds for showers should be south and west of Houston initially, but some areas north and east may see some showers by afternoon. Highs will top off in the low-90s.

Weekend

We’ve had a lot of high clouds and passing moisture overhead this week that’s blocked out the sun at times. We should lose that for the weekend. Expect a return to mainly sunshine, high humidity, and highs in the low to mid-90s and lows in the 70s to near 80 degrees. It will feel like 105° or a bit hotter at times this weekend when you factor in the humidity.

Showers will again be possible both days, but coverage should slack off some, maybe peaking at 20 to 30 percent chances. In other words, if you see some rain, consider yourself lucky. There should be a slight breeze each afternoon but nothing too special.

Next week

There’s nothing particularly interesting about the weather next week as it stands right now. That’s good news in August and September, right? Expect daily chances of thunderstorms to perhaps increase a little each afternoon. But some areas will get drenched while others just hear the distant booms of atmospheric acoustics. Otherwise, expect sun and clouds with highs in the low to mid-90s each day and lows in the 70s, fairly typical for August.

Tropics

It’s tough to make much out of what’s happening in the Atlantic right now. There are a number of possible options for development over the next 5 to 7 days, and maybe one area that’s more clear cut than others (which is assigned a 60 percent chance to develop this morning according to the NHC). We’ll have an update on this Monday and Tuesday. But as of right now, there’s not any model or group of models that’s especially bullish on any one outcome, let alone one that brings it to the Gulf. So we have some time to watch.

Following up on Eric’s post yesterday about NOAA’s seasonal forecast update, Colorado State followed suit on Thursday. They actually reduced their forecast a smidge, though they’re still calling for a season that ends up fairly active in the end. They also released a “subseasonal” outlook, which looks out at the next 2 weeks or so, and it unsurprisingly is calling for a period of above average activity in the Atlantic, something we’ve talked about for a little while now. So we’ll see. The setup in the Atlantic reminds me a bit of what we sometimes see in the western Caribbean or over Central America with what we call a “gyre.” You get a lot of storminess, models hinting at development, but little agreement on which portion of the broader mess becomes dominant. The good news is that it all continues to look mostly sloppy and disorganized for at least several more days.

Lately, I’ve enjoyed opening these posts with a comparison to where we were in 2020 at this time. By August 3rd of last year, we were watching Hurricane Isaias approach the East Coast, and Tropical Depression 10 had recently dissipated. We were actually heading into a lull period, as Josephine would not form for over a week. This year, we remain stuck on Elsa as our last storm. It was great to have a quiet July, but as Eric noted yesterday, we are merely through the easy third of hurricane season. The most likely time for storm impacts here historically is the next 6 to 8 weeks. Of the major hurricanes to strike our region through history (Cat 3+), virtually all have occurred in August or September. The 1909 Velasco Hurricane was an exception, as it occurred in July. So, now is the time to start watching seriously.

Tropical outlook in a sentence

While the noise is going to increase and we are likely to begin to find some disturbances to monitor in the Atlantic over the next week or so, none appear to be overly serious candidates to end up in the Gulf at this time.

Current Atlantic disturbance

The current disturbance outlined by the National Hurricane Center as having a 10 percent chance of developing over the next 5 days is not really much of a concern for us at this point in time. I think we need a little time to start priming the basin, so while this one may make a little noise in the next few days, it seems unlikely to sustain itself.

Most ensemble members of the major models have this thing flailing around for 72 to 96 hours and not doing much. Thereafter, things could change, but that could also be courtesy of another disturbance. Which leads us to…

Next in line

In general, it’s a little noisy in the eastern Atlantic right now, so it’s tough to separate signal from that noise at this early stage in the game, even in modeling. But either the disturbance currently outlined by the NHC or, more likely, another one should begin to try and coalesce from the mess in about 5 to 7 days in the open Atlantic.

At this early juncture, trying to hash out what this does is very uncertain. Right now, the vast majority of ensemble members either kill this disturbance off or have it recurving over the open Atlantic. Few, if any are taking it to the Gulf. We have about 80 different ensemble members between the GFS & European ensemble models, which provides a nice, wide spread of plausible outcomes. But by no means is it a guarantee that we’ll see either of those scenarios (a recurve or a dissipation) play out. But it seems to be the favored outcome at least at this time.

But, let’s focus on the overall pattern as forecast by the GFS and European ensemble models beginning around day 10 to see if there are any clues. Let me start by showing you wind shear. Both the GFS and European ensembles show a fair amount of wind shear setup over the Central Atlantic — for days.

This makes sense at a high level, and this seems to lend some credibility to the idea that whatever does develop may have some challenges in front of it as it moves across the ocean. Closer to home, the shear relaxes a bit, but until we see a disturbance heading that way, it’s not too concerning.

So where will it track? Great question. If we compare the GFS ensemble & European ensemble forecast maps at the 500 mb level (about 20,000 feet overhead) on day 10, I’ve annotated the maps with some notes.

There is a fairly strong high pressure in the upper atmosphere over the ocean. It’s not overly strong, but it may be enough to allow a weaker system to get kicked westward a little farther than perhaps models currently say. The general rule of thumb with Atlantic and Caribbean systems is that a stronger storm will gain latitude faster and a weaker disturbance will be subject to being “bullied” by high pressure and shoved west a little farther. Of course, if this fails to coalesce into a system at all, the point is moot and all the better.

So at this point it’s nothing to worry about because even through day 15, hardly any reliable model guidance has anything of note looking like it will enter the Gulf. But, given the calendar and trajectory of the disturbances out there, Eric and I will be keeping tabs on things, though not talking much unless it becomes apparent that we’re going to have something legitimate to watch.

Beyond this day 10+ stuff in the Atlantic, there will likely be continued background signal support for further disturbances through August 15th to the 25th or so. There may be some signs of less supportive conditions arriving later in the month, and when you factor in some lag time, that could start to assert itself in September. But I’d rather not get my hopes too high just yet. This concerns the “velocity potential” maps we discussed last week. A colleague and PhD candidate at Florida State, Jake Carstens, wrote a great piece on those maps and how they’ve been used to help sniff out this upcoming active period. He did a great job explaining how those maps work and it’s worth your time if you’d like to really get more into some serious meteorological analysis.

Anyway, enough for this week. We’ll see where things stand when we check back in on the tropics next week!