Matt Lanza

Welcome to another edition of our weekly tropical outlook. The last two hurricane seasons have been full of many quick developing, lower-end storms. Some folks deride the National Hurricane Center for “wasting time” naming these things, but if it looks like a duck and quacks like a duck, whether bloated, thin, short, tall, round, square, or what, it’s still a duck. And that’s why we have added another storm since last week.

If you blinked, you might have missed Tropical Storm Danny yesterday, but it formed off the coast of South Carolina, made landfall and weakened to a depression within about 12 to 18 hours. It wasn’t quite like Imelda, and its fast forward motion will keep it from becoming a Carolina or Georgia version of Imelda, but it went quickly, and it came from an area I didn’t even mention a week ago. So go the tropics.

Tropical outlook in a sentence

While there is one area in the Atlantic for us to monitor, it will likely face an uphill battle to make it to the Gulf in a position to develop any more significantly.

Invest 95L

The area people have been watching a good bit since last week is Invest 95L, which today does not pose much risk of making it to the Gulf. It will likely either stay disorganized and continue across the Caribbean (where it will face mountains of shear) or it will develop a little and get pulled north toward the Bahamas, Florida, or Eastern Gulf. Colloquially, some of us in meteorology will use the phrase “weaker, wester” to describe these things. It seems highly unlikely that 95L makes it to Houston. The National Hurricane Center has just lowered odds of development risk on 95L to 30 percent over the next 5 days.

Invest 97L

The one area I want to focus on is the new Invest 97L, which now has a 40 percent chance of developing over the next 5 days according to the National Hurricane Center (up from 20 percent this morning).

As you can see on satellite above, Invest 97L has some loose thunderstorm activity, but it is not yet organized. The one thing about Tropical Storm Danny: Say what you will about it being “pathetic” or whatever, but at least it had that swirly cinnamon bun look going for it yesterday. 97L is not there yet.

Invest 97L will be steered west or west-northwest around the periphery of high pressure in the Atlantic. Both key operational models, the Euro and GFS tend to buy into Invest 97L developing over the next three days. However, they differ significantly on *how* much development occurs. I’ve plotted the GFS and European models below, showing you what we call 850 mb vorticity. What? That’s a good map to look at to gauge where things stand with potential development risk. And you can indeed see both the GFS & Euro show ample “spin” (yellow & orange) and low pressure near the entrance to the Caribbean on Friday morning, with the Euro on the left and the GFS on the right.

The difference is that the GFS is far, far more aggressive in organizing Invest 97L over the next 3 days. Why does this matter? Because the GFS has been the only model showing this coming to the Gulf as a significant storm. If it’s unrealistically strong 3 days from now, that doesn’t bode well for its accuracy on days 7 to 10. So right now, using context clues, there is a good shot we see the potential for a tropical depression or storm approaching the southern Lesser Antilles by the end of this week.

From there, this will have a mountain to overcome. The Caribbean is full of shear, and any system will not be greeted by favorable conditions on the other side of the islands. While the GFS keeps this going somewhat across the Caribbean, the Euro rips it to shreds. Neither model’s ensemble is particularly bullish on this system’s future either. So sitting here on Tuesday, I find it difficult to think that Invest 97L will make it to Texas as an organized tropical entity.

That said, the weather pattern over Texas is likely to say fairly cool and wet for most of the next 2 weeks. It gets tough to think that a tropical system makes it here as an organized system, but a bigger risk could be that the moisture gets here and exacerbates an already wet Texas.

That’s a wet Texas to say the least. So the bottom line is that we’ll want to sort of watch this system for its moisture. But at least at this point there’s no reason to think it’s going to become a problem for us, and I can’t point you to any reliable, outlier model guidance that says it will. We will let you know if that were to change.

Beyond this, expect a quieter tropics for a little while, as the atmospheric background signals (what we often call the “intraseasonal phase” of the atmosphere) is fairly suppressed over the Atlantic basin, meaning it will inhibit storm formation. That doesn’t mean we won’t see a storm or two, but in general, storm development risk should be lower than it has been. This could allow for our first significant Saharan dust event of the summer as well sometime in mid-July. We will see.

We’re starting the day just a tiny bit less humid than yesterday. It has sure felt like summer the back half of this week. The humidity will remain high, but temperatures are going to gradually step back a bit as rain chances kick back up later in the weekend.

Friday & Saturday

Both today and tomorrow should feature mostly similar weather. Expect a mix of sun and some clouds, with highs in the low to mid-90s and lows in the mid to upper-70s, along with fairly high humidity. Rain chances will be pretty typical for this time of year, with at least a few showers or thunderstorms around. There could be a slight uptick in storm chances late Saturday afternoon or evening as the pattern over our area begins to change to one dominated by a trough in the upper atmosphere. This would be especially true south and east of Houston.

Sunday & Monday

Both Sunday and Monday will probably see scattered to numerous showers and thunderstorms. Monday may have slightly more coverage than Sunday, but both days will see considerable chances of rain at virtually any point in the day. Look for highs in the 80s, especially Monday. Lows will be in the 70s.

Rest of next week

The overall weather pattern next week will be a bit odd across the country, with all-time record breaking heat in the Pacific Northwest (seriously, just an incredible and disconcerting weather event up that way, amid a historic drought too; both events carrying the fingerprints of climate change), a hot East Coast, and a cool trough sort of stuck over the Central U.S.

What does this mean for Houston and the surrounding area? Well, it means we shouldn’t see any severe heat next week. Yay, us. High temperatures will actually be held down some because of higher rain chances. Days with more rain will be in the mid to upper 80s. Days with less rain should be in the low-90s. Lows should be in the 70s.

As is often the case, pinning down the exact timing of showers and storms and who will see the most rain is a bit of a meteorological slog; we just don’t know yet how things will precisely unfold next week. But suffice it to say there will at least be chances of rain or storms each day. Right now I’m favoring Tuesday and maybe Friday for the greatest coverage of storms, as the trough tries to reload itself nearby later in the week. But we’ll fine tune that through the weekend.

How much rain should we expect? As of right now, I don’t think this will be a major, widespread excessive rain event. But, a healthy 1 to 2 inches should be expected in most places on average between now and next Friday, with the regular caveats that some places could see more and others a little less. I do think areas south and east of Houston have a higher chance of seeing some of those higher amounts.

At this time, we don’t expect to have to use the Space City Weather Flood Scale, but we’ll be watching closely the next few days to see if that thinking changes.

By the way, it’s a good time to download our weather app, so you can know right away if any changes to the forecast occur this weekend! Tap here for Apple. Tap here for Android.

Tropics

We continue to watch this tropical disturbance (Invest 95L) way out in the deep Atlantic, and also way out of bounds for what is normal this early in the season. The National Hurricane Center has dropped development odds on this one a little since yesterday, sitting at 30 percent as of 1 AM CT.

We’ll get another update not long after I publish this post.

As of right now, we don’t think this has much of a future in front of it as it treks across the Atlantic. Given how out of bounds it is climatologically and a somewhat hostile road west, development, if any, would be very slow and possibly erratic. Probably nothing we will need to ever worry about, but it’s certainly nothing for us to worry about right now.

More on Monday morning or perhaps Sunday, if necessary.

Like we did in 2020, Eric and I are pleased to bring back the “Eye on the Tropics” series to Space City Weather. Each week, normally on Tuesday afternoons, either myself or Eric will write a more detailed post specific to tropical weather in the Atlantic. This allows us to go more in depth on what is happening, what we are watching, and what might be buzzing on social media with respect to tropical storms or hurricanes. We will keep these weekly updates going into August. Usually by mid-August there’s enough happening each day that we’re covering it in our daily posts.

Anyway, we are off to a roaring start this year.

Tropical outlook in a sentence

While we are monitoring the progress of a tropical wave east of the Caribbean islands and some model solutions have brought that or another system into the Gulf as a substantial tropical storm, there is still far too much uncertainty regarding its future to consider it a serious concern at this time.

2021 so far

Before we get to the Atlantic system we’re watching, let’s hit you with some statistics about the season so far. Claudette’s remnants are steaming out to sea in the Atlantic, our third named storm of the young 2021 hurricane season. While Claudette was quite quick to become our third storm, it did not come close to last year’s speed, when Cristobal was named on the 2nd of June. We won’t threaten the fastest to storm #4 either, as Danielle’s record in 2016 is already in the rearview mirror (June 20th). So, at least we aren’t quite pacing 2020 right now. Beyond that, there’s little to deduce based on this season’s activity so far.

Atlantic disturbance

The main thing to talk about this week is a disturbance in the Atlantic basin that the National Hurricane Center is currently giving 30 percent odds of development over the next couple days (Author’s note: Since publication, this has been dialed back to 20 percent odds).

This particular disturbance has probably already caused some folks heartburn as a few social media focused weather pages have irresponsibly shared operational model guidance from Sunday showing a presumed major hurricane hitting Texas in early July. What they don’t tell you, besides failing to offer any context, is that the very same model has subsequently sent a weaker storm to Brownsville, Mobile, the Florida Big Bend, Tampico, New Orleans, and Pensacola in various runs. In fact, I’ve put together a gif of the pinball game the GFS model has been playing lately below.

Again, some of the best advice we can give you, besides not looking at operational model runs to mentally prepare for a storm forecast, is to not waste your time on various Facebook weather pages that don’t identify who the authors are and with whom they are affiliated. But I digress.

So the real question is: Should we watch this system? The answer is yes but with the big caveat that there’s probably a very good chance this develops into nothing. And what some models have latched onto in the Gulf late next week may not even be directly associated with this system.

Looking at satellite imagery of the disturbance in question today, we can see just a disorganized “blob” of thunderstorms approaching the southern Windward Islands.

The NHC going with a low chance of development over the next 5 days seems reasonable based on this. The system is likely to be steered west or west-northwest around the periphery of high pressure in the Atlantic. This should bring it into the Caribbean, where conditions over the next 5 to 7 days won’t exactly be hospitable for development.

So even if this survives the trip, don’t expect it to be particularly healthy looking when it gets to the western Caribbean.

Beyond that, our ensemble guidance is very lukewarm on development and no real model at a place where I’m sitting up straighter in my chair out of concern. There’s some chance this could end up falling apart completely. It may make its way to the Pacific. Or perhaps it does indeed come to the Gulf. We don’t know, but we also don’t see anything notably alarming in model guidance either.

So the advice? Check back in every couple days for the latest, as you normally would during hurricane season. I would not waste energy worrying about this one though. Hurricane season is a marathon. Inevitably we are going to have to watch a storm or two with legitimate interest and concern come later July, August, or September. So pacing yourself if you can is a good plan of attack.

Anything else?

The good news is that beyond this system, there’s nothing else of note in the tropics. With a cold front crossing into our area this week and possibly another one next week, it’s probably best to not write the unexpected off completely. But there’s nothing in any modeling that suggests we need to really focus on anything specific for at least a little while.

Compared to earlier this week, it certainly feels a little more comfortable, with temperatures ranging from the mid or upper 60s well inland to around 80 degrees at the coast.

We will see another day or so of drier air, helping to keep us relatively comfortable, thanks in part to Potential Tropical Cyclone #3 in the Gulf, which will pass to our east into Louisiana. This farther east track leads to a handful of minor forecast changes this weekend.

Today & Saturday

Both today and tomorrow look fairly uneventful in our area, with a mix of sun and clouds. Yes, there could be a stray shower or two that makes into the Houston region, and there could be a portion of an outer band from PTC3 that grazes eastern fringes of our area. But aside from that, it will just be hot and a bit humid. Look for highs in the low to mid-90s (some isolated upper-90s can’t be ruled out) and lows in the 70s. Humidity will likely increase a bit tomorrow, and the morning will feel less comfortable than yesterday or today has felt.

The big weekend change is that rain chances look higher on Sunday than they do Saturday now.

Sunday

We begin a little more onshore flow on Sunday, which means more humidity. Morning lows in the upper-70s seem more likely here. It also means a better chance at isolated to scattered thunderstorms, as a weak disturbance in the upper atmosphere finds a route into Texas and taps into some of that onshore flow. Not everyone will see rain, but there will likely be at least a few showers or storms around Sunday afternoon. High temperatures will be in the mid-90s.

Monday

Right now, Monday looks like a classic June day in Houston with sun, clouds, high humidity, morning lows in the 70s, daytime highs in the low-90s, and a chance of afternoon thunderstorms.

Tuesday & beyond

By Monday night, an actual cold front will be moving across Texas from north to south. We are unlikely to enjoy the cooler, less humid benefits of said front, but we will likely see scattered to perhaps even numerous showers and thunderstorms on Tuesday. Locally heavy rain is possible here, and a healthy chunk of the area should see at least some rain. Expect a less hot day Tuesday, with some chance highs don’t get above 90 degrees.

By Wednesday and Thursday, rain chances won’t drop to zero, but they will diminish a bit as the front fizzles and high pressure begins to nose into the area. Look for highs back in the 90s and lows in the mid to upper-70s.

PTC 3 update

Potential Tropical Cyclone #3 continues across the Gulf this morning. To be honest, this is about as healthy as it has looked in its life cycle since it became an area to watch.

There’s a significant blowup of thunderstorms near and north/east of the center. This is why forecasters have been banging the drum regarding heavy rain being the main concern. Whatever the case, we assume we will see Tropical Storm Claudette come of this mess and approach the Louisiana coast tonight between Vermilion Bay and New Orleans.

Locally, no impacts are expected, aside from perhaps slightly rougher surf and stronger than normal rip currents. Please use caution if swimming in the Gulf this weekend.

The main impacts in Louisiana and the Southeast will be from heavy rainfall. About 4 to 8 inches of rain should fall in southeast Louisiana, southern Mississippi, southern Alabama, and portions of the Florida Panhandle.

Higher amounts will be possible there, but the system may actually move along fast enough now to prevent major problems. But if your travels take you east of Louisiana this weekend, plan accordingly.

We aren’t expecting significant forecast changes this weekend, so look for our next update, as per usual, on Monday morning.