Tuesday PM future Barry update: Holding pattern

Good evening. It’s just a wee bit hot out there this evening, so we hope folks are taking it easy. In this update, we will discuss the latest on the developing tropical system in the Gulf (Invest 92L or “Future Barry”) and what the latest model guidance has suggested.

One sentence summary: Our disturbance is finally heading into the Gulf and will spend the next 24 hours or so slowly figuring out where exactly it wants the center to form before heading west, which means there is still a good deal of uncertainty regarding the final outcome of this system.

Now

Invest 92L is somewhere over the Florida Panhandle or just offshore; there isn’t quite a defined center just yet. This is half the challenge with the forecast. We are relying on models to tell us where the center will form, not basing the forecast off an actual center. So there is some inherent uncertainty in the forecast because of this.

Invest 92L is far from organized this evening, but it is loaded with thunderstorms. (College of DuPage)

With that in mind, there are clearly plenty of storms along the eastern Gulf Coast, and these will slowly meander offshore tonight, allowing for 92L to figure out where it wants its center to form and how that relates to what is happening above it in the atmosphere. We should see a small uptick in track forecast confidence tomorrow morning, followed by perhaps a stronger uptick in confidence tomorrow afternoon.

Today’s modeling

In a nutshell, the Euro held firm, while the GFS trended toward the Euro. Both deterministic models indicate a storm tracking toward and arriving somewhere between Jefferson County, TX and Vermilion Bay, LA. Should that actually happen, impacts in the Houston area will be minimal, but Louisiana would take quite a hit from rainfall and some wind at the coast.

The latest forecast for 92L, or Barry on Saturday morning is shown here, with the ECMWF (Euro) on the left and the GFS (American) on the right. Both deterministic models take this system to Louisiana as of today. (Tropical Tidbits)

But, as I have to hammer home: Deterministic models are never the right tool to use when making a 4 to 5 day forecast, particularly for tropical storms. You need to look at ensembles. As I did yesterday evening, here is a look at the European ensemble’s track density forecast from the University of Albany.

The European ensemble track density outlook favors a Louisiana landfall, but a notable minority of ensemble members still try to bring this to Texas. (University of Albany/Alan Brammer)

This takes the forecast tracks of the 51 ensemble members of the Euro and gives you a “spray” chart to see where clustering for higher confidence may occur, and we clearly see that something like 60 to 70 percent of the ensembles bring this toward Louisiana. But there is still a persistent, call it 20 to 25 percent minority of these ensembles that insist this will come to Texas. Until the center forms, and I can see what modeling is saying at that point, I want to be cautious about being too optimistic that we are going to miss out on impacts from future Barry.

Why the faster turn north on the models today? Some of it may have to do with how 92L’s organization has gone so far, but some of it also likely has to do with the fact that over the last two to three model cycles, this trough over the Great Lakes and Midwest has trended a little stronger.

The upper air pattern has pointed to a stronger trough over the Midwest late this week, which may be aiding in trying to “pull” 92L/Barry more to the north than had previously been shown. (Weather Bell)

The stronger that trough is, the more ability it will have to “tug” 92L or Barry to the north. It may not necessarily capture it, but it could allow it to gain enough latitude fast enough to avoid a date with Texas or even western Louisiana. So that has been helpful for us. But again, until we know where that center is going to establish, we have to treat all individual model runs cautiously.

One final note: Weather modeling did shift a bit stronger with this system as it made landfall, which could indicate that while the ceiling on intensity for this storm may not be at an elite level, it could come ashore as a strengthening tropical storm or even low-end hurricane. So let’s hope that today’s track trends are accurate for us here in Houston.

So the bottom line this evening:

  • Invest 92L is gradually emerging in the northeast Gulf as expected. Over the next 24 hours or so, it will gradually develop a center of circulation that we can lock in on to allow us to gain forecast confidence on track.
  • Weather modeling held on to a shift to the east today, focusing the center and most impacts in Louisiana. 
  • However, a notable minority of reliable data continues to cling to a potential further west scenario, closer to Houston. It’s because of this that we will be keeping our guard up until we get a sense of where the physical center of the storm is going to develop.
  • Modeling also trended a bit stronger with the storm, keeping the idea in play of a strong tropical storm or even low-end hurricane at landfall, regardless of where it goes; another reason to not yet call an all-clear.

We will have another update for you in the morning. Meanwhile, stay tuned in and vigilant and take one final opportunity to make sure your hurricane kits and plans are up to date, just to be safe.

The latest on late week Barry risk and current heat

I will jump into the latest on the potential for a tropical depression or storm named Barry in just a moment. I did go extremely in depth on where we stood last evening with regard to Barry, which you can check out as well. First, we do still have some important weather (heat) to get through before that.

Today & Wednesday

Heat and humidity will dominate today once more. We should shoot for the mid- to upper-90s again this afternoon. Look for potential heat advisories again this afternoon.

Forecast heat index values for 3 PM Tuesday afternoon will be pushing 108° in parts of the area, if not a bit hotter. Heat precautions should be exercised today. (NWS via Weather Bell)

Exercise heat precautions today, stay hydrated, and try to stay in air conditioning if possible in the late afternoon. After some noisy, soaking storms in northern parts of the metro area yesterday evening, we could again see a handful of showers again today, though coverage and intensity should be a bit reduced.

Wednesday looks even worse with high heat and humidity. Expect upper-90s and risk for heat advisories again. There could be one or two showers around but nothing more.

Thursday

We should begin to feel some influence from the potential tropical depression or storm in the Gulf by Thursday, which would just mean a few scattered showers or storms at this point on Thursday afternoon. Otherwise, it will be hot and humid with solid mid-90s if not a little hotter.

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Answering some questions about the late week tropical system

You had questions, we’ve got (some) answers. With the potential of a tropical system (also referred to as Invest 92L or “future Barry”) in the Gulf later this week, I thought I would do a reader-driven Q&A. I looked at comments from our morning post and asked on Twitter what questions folks had, and I’ve chosen some to answer here. I can’t get to a lot of questions in the comments, especially on Facebook, unfortunately simply because of time. So I apologize for that, but hopefully most of what people are wondering will be answered in our at least twice daily posts going forward.

I am traveling from X to Y and I want to know what weather I will encounter. Can you help?

I need to answer this one right out of the gate because based on the volume of questions I’ve seen, it would seem all of Texas is on a beach between New Orleans and Panama City this week. Here is what I can tell you: Given the current forecast, it’s going to be a bit of a stormy period along most of the Gulf Coast between Lafayette, LA and the Panhandle. So expect showers and storms each day scattered about with heavy rain possible in spots, especially Thursday and Friday. I do think travel across Louisiana is going to be challenging later Friday and Saturday before whatever this thing is moves ashore and begins to pull away.

The NWS forecast for Saturday morning shows a tropical system parked south of Sabine Pass, which would likely mean heavy rain along a wide swath of southern Louisiana Saturday. Travel may be problematic there. (NWS WPC)

Houston would likely be free of any serious issues through at least Friday. So if you have travel plans between Houston and points east, it will get progressively worse Thursday into Friday, peak on Saturday or early Sunday, and gradually improve beyond that. That’s the best we can tell you right now.

Do I need to panic? Is this another Harvey? How much rain?

I mentioned this in our morning post, but it needs a bit more prominence here: No, this is not another Harvey. No, you don’t need to panic. You do need to stay aware, however. That storm was unique, and it would take a truly special set of circumstances to see that again. That being said: We always tell you that no two flood events are alike. Whenever there is a risk of heavy rain, there is a risk of flooding in Houston. It will be its own unique event, and given the current rainfall forecast of 5 to 15 inches in the wide region between southeast Texas and southwest Louisiana, yes flooding is a distinct possibility.

The official rainfall forecast has been upgraded today, calling for a widespread 5-15″ on average in and east of our region. This will be adjusted and change with time, but this sort of rain will likely cause some flooding issues in some to be determined places. (NWS WPC via Weather Bell)

Thankfully, this storm should be moving steadily, so we do not believe it will linger down here for 5 days, though storm chances will remain in the forecast into next week. This rain forecast will be fine-tuned in the next few days, so expect some changes, but prepare as if we will be dealing with a heavy rain event in the area this weekend.

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Quiet start to week, but monitoring the Gulf by the weekend

The weekend went about as advertised across southeast Texas with heat and humidity and a distinct lack of rain showers most of the time. We generally topped off in the mid-90s, with warm mornings. Much of this week is likely to play out in a similar fashion. It’s the end of the week when things get more difficult and possible forecast outcomes vary vastly as we will explain below.

Today & Tuesday

We expect both days to carry over the weekend weather: Expect sunshine and hot temperatures. An isolated shower can’t entirely be ruled out, but consider yourself lucky if you see one. We should do mid-90s today and middle to even upper-90s tomorrow.

High temperatures today will sizzle once again. (NWS via Weather Bell)

Take your usual heat precautions the next couple days, as heat index values should top off around 105°, and a few places may flirt with heat advisory criteria.

Wednesday & Thursday

Forecast confidence begins to slump backwards a bit for midweek. As of now, Wednesday looks similar to Tuesday, with mid- to upper-90s and high humidity, sunshine, and limited to nil rain chances. Thursday becomes more challenging. The disturbance to our east in the Gulf of Mexico will determine if we again reach for the upper-90s with dry weather or if we do low- to mid-90s and increasing scattered shower chances. We should hopefully have some clarity on this tomorrow.

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