LATEST UPDATE: Invest 91L Is Trending Stronger & Further West!

[00:00:00]Good morning. It's David Schlotthower here with another detailed update on Invest 91L for Sunday morning, July 19th, 2026. So, to start off the video, here's a look at the latest infrared satellite imagery over the northeastern Gulf of America for your Sunday morning.

[00:00:16]And as we take a look at the infrared on invest 91L for this morning, we can clearly see that the system is getting its act together just a little bit here.

[00:00:26]And in a way where we could actually see where a low-level circulation actually is. If you look at this imagery very closely, we could see low-level cloud filaments in the lower parts of the atmosphere. We can see that happening right about in here towards the end. We can see flow doing this coming all the way around. So we have a circulation. We have westerly wind here on the southern side. We have southwesterly flow here.

[00:00:50]And we have southerntherly flow. So it does appear that we do have a low-level circulation somewhere in here underneath some of the feathery white cirrus clouds on this image. Now while a well-defined circulation does exist here with invest 91L, the convective structure does not allow this to be declared a tropical depression at the moment. But that could change in a hurry if these trends do continue. So when we zoom out here and look at the water vapor satellite imagery across the Gulf of America, we can clearly see where our system actually is here. So that's 91L as we speak. And when we look at the water vapor imagery, you could see a little bit of a tongue of drier air that is working its way into the circulation.

[00:01:34]And that is exactly why we're not seeing persistent deep convection. Although recently we have a huge blossom of thunderstorm activity popping off just to the west of say Sarasota as well as parts of Tampa Bay, Florida for this morning with another batch of thunderstorm activity that is finishing up well to the west of the circulation.

[00:01:55]So therefore that's why this system is having a bit of a tough time getting its act together. But given the fact that we have a robust mid-level and low-level circulation, it will not take a whole lot of time for this to get really organized with a lot of deep convection.

[00:02:10]And we are still looking at a potential tropical depression or tropical storm in the next couple of days. Now, another way to visualize just how defined the circulation actually is is when we take a look at our latest RTMA data at the surface. We can see clearly we have westerly winds here, really strong southerntherly winds on the eastern side of the circulation. Those winds are wrapping all the way around here. So, we definitely have a well- definfined circulation. And it does appear on this map that a low-level circulation is consolidating somewhere over in here, a little bit further to the southwest than what models previously thought. Now, really quickly, when we do take a look at our actual windshare analysis here, this is observed analysis, vertical wind shear over the system, and we can see where our area of low pressure actually is. It's right on the southern side of this neutral environment of vertical windshar of at least 20 knots. So, right now, vertical windshar at the present time over the circulation is roughly anywhere between 10 to 15 knots, which is generally quite favorable. And there's not a whole lot of vertical wind shear surrounding the system. However, we will have to keep an eye on this little area of vertical wind shear off to its northeast coming in out of the easterly and northeasterly direction which will impact the system eventually in the next couple of days.

[00:03:30]Now, when we take a look at the latest National Hurricane Center 7-day graphical tropical weather outlook, you can see clearly they have upped the chances quite considerably right now with a 60% chance of tropical development over the next 2 to 7 days.

[00:03:45]And here is why. Recent satellite wind data and nearby surface observations indicate that an area of low pressure located over the northeastern Gulf of America is slowly becoming better to find. However, its associated shower and thunderstorm activity remains disorganized. Regardless though, gradual development of this system is forecasted and a tropical depression or even a tropical storm folks could form over the next couple of days as this system moves generally slowly northwestward or northnorwestward. interests along the northern Gulf of uh northern Gulf Coast of Florida need to be monitoring this system very closely as heavy rainfall over portions of that region during the next several days are possible. An Air Force Hurricane Hunter recondens aircraft is scheduled to investigate the system later today if necessary and I think they're probably going to have to because of the chances of development that this system is exhibiting. Now, with that being said, let's talk about the intensity forecast with Invest 91L.

[00:04:47]Whether or not will it become a tropical depression or tropical storm Bertha over the next 3 to 6 days. With that, we're going to start looking at the European artificial intelligence forecasting system or Aphys for short. And we can see there's our disturbance really well modeled here. In fact, I believe the artificial intelligence model really got this down very very well with its initialization, which is very important because why it's important is the system is forecasted to really strengthen over the next 60 or so hours. In fact, if we go back in time here, you can see 6 hours, we got 12 hours here. So, Sunday morning, Sunday early afternoon, by the time we go into Monday, it really strengthens. And then by Tuesday morning, it really takes off here. And we do have a pretty good fetch here of tropical storm force winds. That's the green area that you see on your screen.

[00:05:42]And then this darker um color here, that's the orange and red. Those are winds that could be on the order of 45 to 55 mph. I would not even be surprised if winds in this system based on this model reach 60 mph. So, we're definitely looking at a robust circulation with 91L here for sure. And as this goes further to the west, it does drift westward over the next couple of days. So between Tuesday and Wednesday morning, it really does make that run generally westward here. And you'll see that here on the ensemble forecast. And then it gets into perhaps southeastern Texas in about 5 days. And it does show it weakening a little bit, but still this green little patch here is still near or at tropical storm wind intensity here with winds at around 39 to 44 mph. Now looking at the European intensity forecast, the deterministic forecast, not the AI based version, we can see this has also trended stronger as well in this model run compared to the last run. You can see how it was a lot weaker in the last couple of runs and in the recent run it really has shown some strengthening which is not good. We do not like seeing this. We don't like seeing the uptrends at all. And so that's why we are making a video on this in the morning. And so in about 3 days here by Tuesday night into a Wednesday morning, we do have a small fetch here of winds that could reach 45 to 50 m an hour. So we could be looking at storm surge flooding. We could be looking at some very heavy rainfall and some freshwater flooding right along the coast of Florida, which you all do need the rain, but way too much here with this system that's stalling out or moving very slowly could really end badly. So that's why we're really watching the model trends here very closely. So by Wednesday morning, Wednesday early afternoon, the system drifts generally westward here. That's been a new thing on the euro. If we look at the previous run, it was a lot weaker. There was barely a reflection here on the 18Z forecast and even on the 12Z forecast there was barely a reflection. But recently in this run we have seen a much stronger version here leaping towards or agreeing with the artificial intelligence model which the AI is on to something. It's doing a really good job at resolving this and that's why these AI models are really good in in in a sense right. So over the next 5 days, the euro does show this really moving slow. It doesn't move very much at all over the west or the northern Gulf here of America, which is a little bit of a concern with those winds that could be at tropical storm intensity even over the southern tip there of Louisiana. Now looking at the Canadian model, something similar is evolving on this too. We can see uh throughout the day today strengthening does commence that circulation does become more better defined with winds that are nearing tropical storm intensity. Oh wait, no these are not tropical storm winds. Um that's 20 knot winds. I want to make sure the euro didn't show that. Okay, this is not tropical storm intensity. Sorry, the graph is the the legend is a little bit off that it was different on the uh artificial intelligence. So sorry about that. So tropical storm force winds are going to be more up in this middle echelon orange color.

[00:09:06]So here we do have tropical storm force winds here later on in the period into early Tuesday morning, Tuesday afternoon with a 1,1 mibar low over the big bend of Florida. So that's what we're really waiting to see. And yeah, wow. This does get pretty darn strong. You can see a narrow fetch there over Pensacola, Pan Panama City, Florida with with winds that could be on the order of 40 to 45 knots. That's close to about 55 to even 60 m an hour. So, we really really have to watch this. We really do. That's one aggressive model. Um, compared uh to the last run, we have seen huge uptrends in their runs recently. Not a good thing that you want to see here. And then this continues to move further off towards the west. even on the Canadian. So, we have general agreement. Now, this looks to drift generally westward over the next 5 days arriving over the southeastern portion of the coast of Texas within that time frame with winds that are near tropical storm force. And even the Icon model is in agreement with all of our other global computer models.

[00:10:11]Now, you're probably asking me, why am I not going to be showing the GFS model?

[00:10:16]It's because it is a huge outlier. It literally shows no development with this system whatsoever. And it's again, it's a huge huge conservative outlier for some reason. And the GFS has not done very well for some reason in other aspects. Hopefully, they get down to the bottom of that soon. So, looking at the German model, we can see the system does strengthen a little bit here with winds again between 30 to 40 mph. That system generally moves off towards the west and really parallels the coast here of Louisiana, bringing a lot of heavy rainfall. In fact, if we just look at our rainfall uh associated with this system, there is definitely some yuckiness to the forecast here for the southern coast of Louisiana. Moderate to heavy rainfall and maybe some minor or marginal flooding is expected or potentially possible. Now, there is one other model that I wanted to show you all since we did get our hurricane models in recently. We have the Hwarf model that has done a great job with this system so far and it seems to have a better handle with it than our other hurricane models. And this is a look at invest 91L once again. You can see the moderate to heavy rainfall. Really, really well done here with that deep convection that we're seeing already initializing. That's what it was forecasting and it seems to be panning out right now. So that's why I'm putting a little bit more reliability on the Hwarf model. And so as we go forward in time here, the Hwarf model does show a consolidation of a surface low here with some pretty good banding futures to the south of the system. You can see even what appears to be a partially formed eyewall like future here, which is not what you want to see. You don't want to see that. That means a the system is trying to intensify. It's trying to show signs of it trying to become a high-end tropical storm with winds of 70 plus miles an hour. But the good thing is there will be some vertical wind shear on this system preventing any significant intensification as we as we see or as far as I can see little bit of heavy rainfall even on the coast here of Florida. So like Tallahassee could get some banning futures with associated with this system and this is going to continue um for a while. You can see system really does try to take shape here over the course of the next 84 hours. So it does move onshore potentially over Louisiana here on this particular run with some moderate to heavy rainfall. And the surface low here I believe if we get our mouse readout we can bring that up. Surface pressures here are at 998 millibars. That's what the model is picking up on. And they get down. Yeah. So they pretty much bottom out here at around 9990 about 992 993 millibars as this generally moves towards a west northwest. So now that we looked at the intensity forecast, let's take a look now at the track guidance forecast with our tropical like disturbance that is developing and evolving rather quickly over the northeastern Gulf of America. So one thing that has been the thing in recent models is this ridge of high pressure.

[00:13:22]So, we know this high is here over the desert southwest. That's what's bringing the monsoon over the four corners region. We have a trough that is now exiting the picture over the northeastern United States. So, what that's going to do is it's going to open the door for this ridge right here to nestle in towards the east here to build gradually towards the east and this ridge to help to absorb and just kind of form to the north of our system. So what you see here on the model now is we have had a recent conclusion here on the forecast that this trough the next trough that arrives will arrive a little too slowly and a little too late before this ridge is able to develop. So therefore this system right here that is over the northeastern Gulf gets mired underneath that ridge. It gets caught underneath and gets captured. So, what we end up seeing here is a system that gets that pretty much moves generally off towards the west here as it's being felt by this steering flow generally out of the easterly direction helping to steer our storm generally westward at about 10 to 15 or even close to 20 mph as this high pressure remains to the north of our disturbance. And then after that period um that system could reemerge out in the middle of the Gulf or not the Gulf over um the eastern Pacific as a mid-level wave trough like future right here. You can see that as this high continues to remain quite dominant. That has lend to some confidence in the track guidance forecast here as far as where this system could be headed. Right now, we think in the short term the system could pivot towards the north here briefly as the vortex becomes more stable and better aligned. And then once that occurs and it gets captured and get m gets mired underneath that mid-level ridge to the north, the system is likely to take a sharp turn off towards the west and parallel the Louisiana, Mississippi, and Alabama coast over the course of the next 3 to 6 days once that westward jog does begin. Now, another thing that is important about this is if this does spend more time over the Gulf and the how can that actually happen, you might be asking is, well, if it spins further offshore, uh, so if you get a track like this, it has more time over the water versus a track that looks something like this that gets a lot closer to the land area here of Louisiana, Mississippi, and Alabama. It spends lesser time over the water, which means it's not able to get as strong. So that's why members that are closer to the coast are weaker. Members that are further away from the coast are stronger. That's why we see green lines here indicating winds of 40 to 50 knots.

[00:16:05]On the European though, this is a very very concerning alarming evolution that we have seen in the last few ensemble model runs from the euro over the next six days. Uh while in the short term not much strengthening is expected, that's because the system is still in its formative stage. But if it takes a jog far enough south here over the very warm Gulf waters that are running in the mid to almost upper 80s, uh this model in particular, I cannot just be one biased person over one ensemble family. That's why we look at all the spaghetti plots thoroughly. But on this particular plot, it is showing a major hurricane. And some of these members, actually, most of these are in hurricane intensity territory with winds that are greater than 65 to 70 knots. That is a hurricane unfortunately uh for the southern uh portion here of Louisiana into Texas.

[00:17:01]Now, will this verify? It is very very hard to say but there is some reasoning behind this because now our system is going to be captured underneath that ridge and it's going to be able to move a little bit faster and unfortunately could get devoided from any vertical windshar less vertical windshar is a little lesser. The GEFS ensemble is not very optimistic uh for some reason. I don't know what has been going on with this model. So we're just going to kind of move on from that. The Google Deep Mind AI is a lot more aggressive here.

[00:17:33]Uh very aggressive with a lot of greens and even some yellow colors indicating winds between 40 to 55 knots. That is definitely in realm of tropical storm intensity. So that's what we're really to be watching for. Uh and because of this and because the National Hurricane Center has upped their chances, I am pretty confident that this is going to get named. I don't see why this does not get named at all in the northern Gulf over the course of the next say uh 3 to 6 days. And on the Google generational control forecast member ensemble, we can also see a lot of green lines here, green tracks, even a couple of orange tracks which indicate a midgrade tropical storm is not out of the question here. So therefore, we are going to really really need to watch this. Okay, I know a lot of you on this video are going to say, "Oh, I don't think it's going to become a tropical storm, David. It's too close to land."

[00:18:28]Well, that's right now, but what is it going to do? Well, which will determine its fate into the future. Right now, I'm going with the tropical storm. I think this is going to earn its name. And here's a look at the latest spaghetti plot on our hurricane specific models.

[00:18:43]Some of these are not hurricane models, but you get the general idea. Most of the guidance is aiming towards Louisiana and Mississippi as a lowgrade tropical storm here in the next 3 to 4 days. Keep in mind some of these members take 4 days 4 days just to get up to this point which means it has 4 days to get its act together to where it can organize enough and become a tropical storm. That's the concern is it spends that much time go it goes from here to here in 4 days.

[00:19:15]That's pretty slow for a tropical like disturbance. When we look at the intensity forecast, this has been nudged upward from the last forecast. We can see more models now in the realm of tropical storm intensity. And because of this and because of the confidence on the ensembles that we just looked at, I am bringing my intensity up on this system. Now, I'm calling for this Invest 91L to become a tropical storm Bertha with winds that could reach about 45 to almost 50 mph. So, yes, if you're asking a question about will this become a tropical storm, I am now officially saying in this video it is going to get named it will become a tropical storm in the next 2 to 3 days. But anyways, if you did find this video very helpful, detailed, informative, and life-saving on Invest 91L as it rapidly evolves here over the northeastern Gulf of America, please don't forget to subscribe to the YouTube channel, folks. It really means a lot to me. You all did a great job in my last couple of videos at subscribing and showing your diligent support because we are going to go live on this potentially this afternoon on the YouTube channel. Don't miss it. We are going to potentially go live on invest 91L discuss about what I think is going to happen and we might even bring some people on the live stream as well to help out with it. So again, if you have not subscribed to the channel, please consider doing so. It does mean a lot.

[00:20:46]Hit the like button, share this video with your family and friends on social media, and also leave a like. I'll be back with you more this afternoon with another video or live stream update on Invest 91L.