Matt Lanza

August 24, 2023 Outlook: Franklin drifts north, while eastern Gulf development odds increase

One-sentence summary

While the Gulf or northwest Caribbean may see action next week, Tropical Storm Franklin is on its way away from the Caribbean islands and will meander north over the next few days.

Tropical Storm Franklin maneuvering north

Franklin has exited Hispaniola and is on its way north today. It is slowly trying to get its act together.

Franklin has moved north of the islands and will slowly gain strength in the coming days. (Tropical Tidbits)

Maximum sustained winds are 50 mph, and you can see from satellite that there’s a pretty healthy burst of convection (or thunderstorms) indicated by the deep red cloud tops showing up north of Hispaniola. That said, Franklin is not yet really organized, as almost all of these thunderstorms are to the east of the center of circulation.

Franklin will drift northeast over the next few days before being shunted back to the west a bit. It may

Franklin’s track is interesting but makes meteorological sense. It will continue north and turn northeast, but as high pressure builds west a little over the Central Atlantic, Franklin will slow down and turn back northwest or north, before continuing north and northeast and eventually out of the picture. The challenge regarding Franklin is that exactly where this maneuvering occurs will determine what sort of impacts are experienced on Bermuda — and for that matter, Atlantic Canada. Model consensus overnight shifted Franklin’s track a little farther west; good news for Bermuda. Folks in the Maritimes will want to monitor Franklin’s progress as it comes north next week. Anyone on the East Coast should probably expect a bit of rough surf and rip currents to become an issue later this weekend or next week as well.

We’ve seen most storms struggle this year, and Franklin has been no exception to date, but as we go into the next few days, Franklin should find a more hospitable environment in which to organize, which should lead to it becoming the season’s second hurricane.

Gulf & western Caribbean mischief

Yesterday evening, the National Hurricane Center dropped a lemon (20% development odds) on the map for the potential of development in or near the Gulf of Mexico next week. Today, that’s an orange, with a 50 percent chance of development over the next week.

The National Hurricane Center now gives the Gulf area a 50 percent chance of development over the next week. Keep in mind that the “hatched” area on the map above indicates where a system may form, not where it will track. (NOAA NHC)

As noted in the caption, it’s important to remember that when the NHC posts these hatched development regions, they are showing what region they believe a system may form, not where it will track.

Models have been oscillating back and forth on this area for days now. The overnight GFS operational run delivered a sheared, disorganized batch of moisture to Cuba and Florida. No organization. The overnight operational European model brought a tropical storm-type system north of Tampa.

A look at the ensembles this morning shows some decent consensus that is not that different from the operational guidance: The GFS ensemble is unenthused overall, while the European ensemble is excited, though generally low-end on intensity. Remember, ensembles run each model 30 to 50 different times with some tweaks to produce a more realistic “spread” of outcomes. We need them because single deterministic (operational) models give us no real forecast uncertainty gauge. You need that, especially with tropical storms. The map below shows the two ensemble groupings and their spreads so you can get a sense of what we’re looking at.

A look at the two ensemble spreads for next Wednesday evening shows that most GFS ensemble members (right) struggle to develop this, while most European ensemble members develop it in some capacity, though they disagree on intensity and obviously the exact track. (Weathernerds.org)

Based on those maps, what we see in operational guidance, and what we know about the Gulf and northwest Caribbean, what can we say today?

Well, for one, we are fairly confident that whatever happens will track north and/or northeast. The weather pattern next week favors west to east or south to north moving winds over most of the central and eastern Gulf of Mexico. This should steer whatever develops (if anything) to the north and/or the northeast. So for folks in Texas and Mexico outside the Yucatan, keep tabs, but this is probably not going to be a big concern. For folks from eastern Louisiana eastward and especially in Florida, it is a good idea to continue watching. Perhaps it’s just an uptick of rain chances instead of an organized tropical system that you see next week, but it’s far too early to say which outcome is more likely right now. We will keep you posted.

Elsewhere

The good news is that there are no other items of concern for land anywhere on the board right now. Emily’s remnants continue to look likely to regenerate into a tropical storm over the open Atlantic, west of the Azores. Invest 92L still has an outside shot at developing over the next 5 to 7 days.

August 22, 2023 Outlook: Tropical Storm Harold arrives in Texas, while Franklin struggles in the Caribbean

One-sentence summary

Tropical Storm Harold will make landfall soon near South Padre Island, TX bringing rain and storms to Texas and Mexico, while Tropical Storm Franklin is struggling in the Caribbean but still aiming to bring heavy rain to Hispaniola.

Tropical Storm Harold

Tropical Depression 9 was upgraded to Tropical Storm Harold overnight. In a twist of minor irony, Harold will make landfall about 100 miles south of the storm whose name it replaced (Harvey) on the Texas coast in about 4 to 6 hours.

Tropical Storm Harold is just a few hours from making landfall, likely near South Padre Island. (NOAA NHC)

Harold is struggling a bit this morning in terms of organization. It has 45 mph maximum sustained winds, but it is clearly dealing with a hostile environment for quick organization. There have been wind gusts as high as 46 mph in Corpus Christi and south of there, mostly in heavier showers.

Wind gusts have been as strong as 46 mph in Corpus Christi and also in Kenedy County. (NOAA)

Showers and storms are pushing across South Texas this morning and into Mexico. Steadier rain is waiting offshore and looks as if it will push into Corpus Christi and points south for the later morning. The Valley may see more intermittent rain and thunderstorms.

Numerous thunderstorms are moving ashore from Harold from Matagorda Bay south into the Valley and Mexico. The steadier rain associated with Harold will move in near Corpus Christi and just south of there for the later morning and early afternoon. (RadarScope)

Within these thunderstorms, as occasionally occurs with tropical storms, isolated tornadoes are possible. Even some of the more intermittent and isolated showers well north of the center (toward El Campo or Victoria or just south of San Antonio) could produce an isolated, brief spin up. Something to be aware of in South Texas today.

Total rainfall will be on the order of 1 to 4 inches in South Texas, with the highest amounts just west of the Lower RGV back toward Laredo and into Mexico, where totals in isolated spots will approach 6 to 10 inches. Some of the rain may be heavy enough to produce isolated landslides in the mountains of Mexico, and flash flooding is possible in northern Coahuila and northern Nuevo Leon.

Rain will be welcome in South Texas, but in portions of northern Mexico it may produce some flash flooding or isolated mountain landslides. (NOAA)

Harold will quickly move inland today and tomorrow, and it should be into the Desert Southwest, aiding in some rainfall by tomorrow evening.

Tropical Storm Franklin

We’re all having a bit of a difficult time finding the exact location of Franklin’s center this morning, as it is presumed to be drifting northwest in the Caribbean.

Tropical Storm Franklin is very disorganized this morning as it presumably drifts northwest in the Caribbean. (Tropical Tidbits)

If you look at the satellite image above, you can just see South America’s coast at the bottom and Puerto Rico at the top right. Hispaniola is in the middle near the top. The bright colors indicate deep, intense thunderstorm activity. If you look closely, you’ll notice that the main area of storms is actually being pushed south. There are also a bunch of lighter looking clouds moving left to right toward those storms. That indicates a whole lot of wind shear in the atmosphere. Tropical storms do not like wind shear, as it inhibits their development. Overall, Franklin is a moisture-laden but extremely disorganized tropical storm. It’s not clear that Franklin will get much better organized over the next couple days as it moves north toward Hispaniola.

Tropical Storm Franklin should move across the Dominican Republic tomorrow. It may find a slightly better environment for organization once it gets out into the open Atlantic. (NOAA NHC)

Overall, Franklin’s main concern for people will be heavy rainfall, capable of producing flooding over Hispaniola, particularly in the Dominican Republic. The models differ on exactly where the heaviest rain will be, but they all put it in the southern Dominican Republic. The greatest uncertainty may be in southeast Haiti, where models have waffled a bit between manageable rainfall and some higher totals closer to 10 inches.

Rain totals continue to look significant over the next 2 to 3 days in Hispaniola, with 10 inches or more possible in spots, which will lead to flash flooding and the potential for mudslides. (Weathernerds.org)

Flash flooding and mudslides are possible across the Dominican Republic as Franklin passes by. Beyond Hispaniola, Franklin’s future remains up in the air. Modeling suggests it will likely become a hurricane over the open Atlantic. Exactly how close this gets to Bermuda on its way north is to be determined. There are even a couple model solutions now suggesting that Franklin comes even a bit farther west toward the Southeast coast a bit. I don’t want to speculate too much on this, particularly given that it’s currently tough to even figure out where Franklin’s center is. Bermuda should monitor Franklin’s progress closely, and folks on the U.S. East Coast should at least keep tabs on what’s happening in a couple days.

Other Atlantic systems

Tropical Depression Gert, east of the islands should dissipate today. Tropical Storm Emily dissipated yesterday. That is still on the big board, however, with a 20 percent chance of redeveloping in the open Atlantic as it curves out to sea.

The next system, Invest 92L, continues to plod along west of the Cabo Verde Islands. Development odds are down to 50 percent this morning, as a very slow organizational process may occur with this system. I think if it’s like most Atlantic systems this year, there’s something likely to act against it and who knows if it can truly get off the ground. We’ll see.

Invest 92L west of the Cabo Verde Islands will struggle to get off the ground in the next few days. (Weathernerds.org)

That covers all the noise out there right now.

Fantasyland (beyond day 10): Mired Gyre

The only other area really showing up at all on modeling as a development risk is off the Yucatan at some point on a few models (not the majority). We’ve discussed this whole gyre thing for several posts now, and maybe it comes to fruition, maybe it doesn’t. There’s enough signal in the model noise to say there’s a meaningful chance it could happen. But exactly what that looks like, I’m not sure. The overall background state of the Atlantic may actually become more hostile to tropical development in the early days of September, perhaps allowing us to catch our breath before the season finale and/or curtain call. The 2023 season to date has thus far been an example of quantity over quality which hopefully continues to be the case.

Tropical Depression 9 heading to Texas; Franklin a flood threat in Hispaniola

One-sentence summary

Tropical Depression 9 will move into South Texas, where tropical storm warnings are now posted, with gusty winds and heavy rain tomorrow.

TD, TD Number Nine

The National Hurricane Center upgraded Invest 91L in the Gulf to Potential Tropical Cyclone 9 this morning and since its potential has been realized, it is now Tropical Depression 9. Despite these changes, they were mostly expected, and not much has changed from our morning post in terms of expected impacts in Texas and Mexico.

Tropical Depression 9 is expected to become Tropical Storm Harold tonight before making landfall in far South Texas on Tuesday morning. (NOAA NHC)

Tropical Storm Warnings are posted along the Texas coast from the Rio Grande River north past Corpus Christi to Port O’Connor. A Tropical Storm Watch extends north from there to Sargent, TX. Looking at TD 9 on satellite this afternoon shows a whole lot of storms. I said it this morning, and I’ll say it again. We are fortunate that this thing has a limited amount of time left over water.

Tropical Depression 9 is rather well defined over the Gulf this afternoon, and slow strengthening overnight seems likely before it runs out of water to feed on. (Tropical Tidbits)

It has all the ingredients you need in place to blow up into a big storm, except the most critical thing: Time. The depression is racing west at 18 miles per hour, which means it will be ashore in Texas by Tuesday morning. Impacts will be minor to moderate in South Texas, with the potential for some gusty winds to tropical storm force, mainly south of Corpus Christi and offshore. Meanwhile, beneficial rain will fall in South Texas, where generally 1 to 3 inches will fall. There will likely be a few pockets of 4 to 5 inches in Brush Country and more into the mountains of Mexico.

Rain totals of 1 to 3 inches, with pockets of 4 or 5 inches are likely in much of far south Texas into Mexico. (NOAA)

Rainfall impacts will be minimal north of there, with Houston and San Antonio mostly missing out on anything. In fact, with a bit of a breeze in between the heat ridge to our north and TD 9 to our south, we may have a slightly enhanced risk of fire danger in parts of Texas again on Tuesday. When it fails, it fails hard.

In addition to heavy rain in South Texas, there is also a chance for isolated tornadoes, as is often the case with landfalling tropical systems. But the main issue to impact your daily life in that area will be heavy rain.

By Wednesday, TD 9 or Harold will make its way across Mexico, and a piece of its remnants may actually find its way into the monsoon flow in New Mexico and Arizona, which would bring some beneficial rain to those areas that mostly missed out on Hilary’s rainfall this past weekend. Rare is the tropical system that is mostly a net positive, but PTC 9 may very well be just that. We’ll keep an eye on rain totals tomorrow to make sure things stay under control.

Elsewhere: Franklin looks to be a big rainmaker in Hispaniola

Franklin’s forecast is mostly unchanged over the next couple days, except for rainfall. There was a bit of a healthy shift west in the highest forecast totals over the next 3 days, which brings the heaviest rainfall a little farther west in Hispaniola, closer to the Dominican Republic border with Haiti.

The heaviest rains from Franklin will fall on the southern coast of the Dominican Republic, but some model guidance has nudged the bullseye west a bit, closer to the border with Haiti. (Weathernerds.org)

Flooding is likely in the southern portion of Hispaniola. Obviously this area is occasionally susceptible to bad bouts of flooding, so hopefully preparations are being made to manage this as best as possible.

Franklin is still expected to come ashore as a tropical storm, though I suppose the odds of a low-end hurricane are not zero. Regardless, the impacts will be similar. As much as 10 to 15 inches of rain may fall on parts of Hispaniola, particularly in the southern Dominican Republic. There’s a good deal of uncertainty on what happens beyond Hispaniola as it lifts north into the Atlantic, something we’ll try to hone in more on in the coming days.

We’ll have more on both of these systems in the morning.

August 21, 2023 Outlook: Gulf tropical wave chugs west toward South Texas; TS Franklin to drench parts of the Dominican Republic

One-sentence summary

A tropical wave in the Gulf offers a slight development chance and some beneficial rains for south Texas, and of the three tropical storms in the Atlantic this morning, only Franklin needs watching for land impacts in Hispaniola.

Tying a bow around Hilary

We hope that all our new readers in California and the Southwest are doing ok this morning after Hilary’s rains yesterday. It sounds as if the mountains and some parts of the desert were particularly hard hit overnight with numerous debris flows, mudslides, and road washouts reported. A better assessment of the damage should emerge today.

While we are a tropics-focused site, we hope you’ll find our information interesting to share with your friends and family. And we may cover more than just hurricanes here eventually, in which case California would be a focus of ours. We are happy to have you here.

Gulf system & Texas rain

First up today, let’s talk about the Gulf of Mexico. We have seen no real progress toward better organization overnight from the tropical wave, Invest 91L in the eastern Gulf.

Invest 91L is not much better organized this morning, which may be a good thing given its size and the look it has on satellite. It still has a better chance than not of becoming a depression or tropical storm before reaching Texas Tuesday morning. (Weathernerds.org)

Just as a quick reminder: Invests are really just meteorological classifications given to tropical disturbances so extra data can be compiled about them; literally “an area of investigation.” There’s no strict definition, but they go from 90 to 99 and then recycle again. In the Atlantic we use “L” as an identifying abbreviation. The East Pacific is “E,” West Pacific “W,” etc.

Anyway, 91L has a broad circulation this morning but does not appear to be tightening up any as of yet. The good news is that this system has about 24 hours left over water before it comes ashore in South Texas. The most likely outcome at this point is an approach just south of Corpus Christi or north of Brownsville.

The most likely track of 91L brings it between Corpus Christi and Brownsville in South Texas, though it’s not out of the realm of possibility that it comes in south of the Rio Grande Valley in Mexico. (Tomer Burg)

Given that we have 24 hours left and given how this thing looks on satellite, my hunch is that if we see this upgraded we may skip the formalities and go right to a tropical storm. The next name on the list would be Harold. At worst, this would probably become a low-end tropical storm (45 to 55 mph maximum sustained winds, mostly in heavier rain bands and over water).

More importantly, this will be a rainmaker for Texas. The entire state desperately needs rain.

Drought is getting extreme to exceptional in much of Texas. Rainfall from a steadily moving tropical system would be mostly welcome at this point. (US Drought Monitor)

East Texas and the upper Texas coast are in extreme drought, with pockets of exceptional drought in Hill Country northwest of San Antonio. A quick moving tropical system would be virtually 100 percent positive in Texas right now. This will help. Rain totals of 1 to 3 inches with higher amounts are expected for South Texas, mainly south of Corpus Christi into the Rio Grande Valley and west toward Laredo. Northern Mexico will also receive healthy rains from this.

Rainfall of 1 to 3 inches on average will be expected in South Texas, with pockets of higher amounts in parts of Brush Country and in the mountains of northern Mexico. (Pivotal Weather)

While this will not end drought for South Texas, it will greatly help. Unfortunately, the hardest hit parts of the state are expecting little to no rain this week, meaning drought and fire danger will worsen. See our companion site, Space City Weather for more on that.

Franklin to turn toward Hispaniola

Yesterday afternoon, Invest 90L in the Gulf was upgraded to Tropical Storm Franklin. Franklin is impressive looking this morning, less so for organization and more for how much moisture it is carrying.

Tropical Storm Franklin should make a hard right tonight toward Hispaniola, bringing very heavy rain to the Dominican Republic. (NOAA NHC)

Franklin is expected to turn to the north, almost like something you’d see in autumn. Why? An upper level low and a fairly deep trough for August over the western Atlantic will act to scoop it up, as high pressure over the southern Plains effectively acts as a “block” to letting this come west.

The sun rises on a moisture-laden Tropical Storm Franklin in the Caribbean (Tropical Tidbits)

So Franklin will make a hard right toward Hispaniola tonight or tomorrow. Exactly where this turn happens will determine where on Hispaniola Franklin comes ashore. This will have implications on specific rain totals for both Haiti and the Dominican Republic. As of now, the heaviest rains from Franklin are poised to hit on the Dominican Republic side of Hispaniola, where upwards of 8 to 12 inches or more will be possible, especially in the eastern part of the country.

Flooding is possible there, and some of it could be relatively significant, in addition to tropical storm conditions. For Puerto Rico, you’ll be on the eastern flank of Franklin’s circulation, which should allow for occasional bands of rain to push north into the island, and this too could lead to some more localized heavy rain or flash flooding issues with totals of 3 to 6 inches possible in the worst cases.

Franklin will likely hit Hispaniola as a moderate to strong tropical storm. The island will weaken it somewhat as it emerges to the north, but then it may find a more hospitable environment out ahead of it to gain strength. There is a good chance we could have Hurricane Franklin by the end of the week over the open Atlantic. Initially, Franklin will turn north or northeast. Except there’s a bit of a problem. Models indicate a ridge in the eastern Atlantic may try to build west enough to bump Franklin back off to the northwest, which means there is at least some chance Bermuda will be in play for this as it goes north. Eventually Franklin will turn back out to sea, but where that happens relative to Bermuda is impossible to say right now. So interests in Bermuda will want to follow Franklin’s progress closely in the coming days.

Additionally, if Franklin can get its act together in the Atlantic, there may be some rough surf and rip tide conditions possible on the U.S. East Coast next weekend.

The rest of the Atlantic

Tropical Depression 6? Now Tropical Storm Gert and soon to be history. Tropical Storm Emily formed yesterday from Invest 98L, and that should dissipate today. It is no threat to land. Behind Emily, we have Invest 92L, which has a solid chance at becoming a named storm in the next few days.

Invest 92L will gradually get its act together and has a good chance of developing while on its way out to sea in the open Atlantic. (Weathernerds.org)

It will likely also turn out to sea.

What’s next?

Looking out in time, once we unclog the Atlantic of the current logjam of systems, we can focus our attention more on two areas. One will be the potential that a system can spin off a potential “gyre” circulation over Central America, but that is looking a bit less impressive today than it did last week. The other area will be off Africa, where additional waves may emerge and threaten development in the next couple weeks. In truth, nothing looks especially concerning right now as we head into the start of September. Obviously, we’ll keep you posted.