Tropical Storm Alberto flinging heavy rain and storm surge at the Texas coast

Headlines

  • Tropical Storm Alberto will head for a landfall in Mexico tonight, but its broad circulation is delivering rain, gusty winds, and tidal flooding impacts up and down the entire Texas coast.
  • Behind Alberto, the next Gulf disturbance looks to try to track a little to the south and struggle to develop, but it may deliver a flooding risk to Mexico.
  • The system nearing the Bahamas continues to look relatively unimpressive and should not have a meaningful impact on Florida at this time.

Alberto arrives

The first named storm of the 2024 Atlantic Hurricane season is officially with us now, as Tropical Storm Alberto was declared this morning. Alberto is as lopsided a storm as you’ll ever come across. Winds of tropical storm force extend out 415 miles north of the center and maybe 25 miles south.

Tropical Storm Alberto will quickly scoot ashore in Mexico tonight. (NOAA NHC)

The National Hurricane Center says that Alberto has 40 mph maximum sustained winds. We’ve seen frequent gusts all the way up into the Galveston area of 40 to 45 mph or even a bit stronger at times, which is about on brand for a storm of this nature. Persistent easterly flow across the Gulf and the large swath of wind accompanying Alberto has made its storm surge perform in an outsized manner for a typical low-end tropical storm. For instance, San Luis Pass, just southwest of Galveston is experiencing a surge level around 4 feet at the moment.

Click to enlarge and see tide levels at San Luis Pass, which is on the cusp of “major” tidal flooding. (NOAA)

For some places, the tide levels will meet or even come close to exceed the levels met during Hurricane Nicholas in 2021. Either way, this is the highest water in a few years on the Upper Texas Coast. You can view a wide range of tide gauges on this special NOAA site for Tropical Storm Alberto.

Meanwhile, rainfall continues to add up. It was slow to start last night and this morning, but it has kicked into gear today. We’ve seen squalls with strong winds, possible tornadoes, and rain rates currently approaching 2 inches in an hour with storms passing through Rockport, Fulton, and Sinton north of Corpus Christi. Storm totals so far are as high as nearly 5 inches just east of Rockport.

12 hour rainfall is on the order of 1 to 4 inches on average from just north of Corpus Christi across to Matagorda Island south of Port O’Connor. (NOAA NSSL)

Rain, squalls, and thunderstorms will continue to push ashore this afternoon and evening along the Texas coast, with a few spots seeing several more inches of rain perhaps, especially from near Surfside Beach southwest of Galveston into South Texas.

Showers, squalls, and thunderstorms will continue to push inland from Alberto south of Houston into South Texas through the afternoon and evening. (College of DuPage)

This rain is deceptively heavy, as evidenced by some torrential downpours in Houston this afternoon leading to localized street flooding. And combined with high tides, watch for flooding along the bays of Texas, as well as the Gulf waterfront. Even parts of southwest Louisiana, as expected, are dealing with tidal flooding. The worst of tidal flooding should be occurring now, or shortly, with a gradual decline in tides tonight and tomorrow as the winds slowly ease up.

Again, also be mindful of waterspouts or quick tornadoes along the coast, particularly from Matagorda Bay into far south Texas.

Total additional rainfall will be on the order of 4 to 8 inches in South Texas, including the metros in the Valley between Laredo and Brownsville. Flash flooding remains possible there. Higher amounts will likely occur in northern Mexico, with upward of 16 inches of rain in the mountains and a risk for mudslides and flooding.

An additional 4 to 8 inches of rain is possible in South Texas, including the Valley, with amounts as high as 16 inches possible in the mountains of northern Mexico. (NOAA NHC)

Alberto should release its grip on Texas and Mexico weather after tomorrow.

What’s next for the western Gulf?

Once Alberto gets out of the way, these areas will get about 2 days of quiet weather before the next iteration of the Central American Gyre kicks into gear.

You can see on the GFS model that once Alberto enters Mexico, a new system will try to form off the Yucatan and track into Mexico near or just south of where Alberto traveled. (Tropical Tidbits)

The good news is that the National Hurricane Center is maintaining low odds of development with this next system. The other good news is that modeling is tracking this thing farther south than Alberto, so hopefully it avoids repeating the exact same outcome over South Texas and northern Mexico that would lead to a higher likelihood of flooding the second time around. It also looks less impressive than Alberto did on model guidance to this point, so I think we’re setting up for a lower-end system, maybe a depression moving into central Mexico on Sunday or Monday.

Rainfall forecast between Saturday and Tuesday for South Texas and northern Mexico from the ECMWF model shows about 1 to 3 inches possible. Higher amounts would be possible in portions of Mexico. (Weather Bell)

For now, look for something like 1 to 3 inches on average south of Corpus Christi into Mexico. Models indicate that especially in the Sierra Madre Oriental just inland from the coast of Mexico could see upwards of 5 to 12 inches (125 to 300 mm) of rainfall. So flooding will be something to watch in Mexico, with or without a defined tropical system.

Off the Atlantic coast

The NHC continues to advertise about a 20 percent possibility of development from the disturbance in the Atlantic Ocean that will work toward Florida in the coming days.

A 20 percent possibility of development is still all that can be garnered from another tropical disturbance in the Atlantic heading toward Florida. (NOAA NHC)

This does not seem likely to develop, and even if it does, it will be doing so in an environment that’s less than ideal for strengthening. So there should be a pretty firm cap on how strong this can get. Either way, rain chances may pick up a little in Florida or the Southeast next week, but that should be about all.

Elsewhere, things look quiet for now. There were some operational model hints that perhaps this Atlantic system could get pulled into the Gulf and try to slowly organize, but those are low impact, outlier scenarios right now and we won’t be taking them seriously at this point.

Potential Tropical Cyclone 1 will potentially bring flash flooding to South Texas and Mexico

10 AM Wednesday update: PTC 1 is now Tropical Storm Alberto. We will have an update early Wednesday afternoon on the rain and surge issues impacting the Texas coast.

Headlines

  • Potential Tropical Cyclone #1 to bring marine impacts and heavy rain to portions of Mexico and Texas over the next couple days where flash flooding is quite possible.
  • Atlantic development remains fairly unlikely east of Florida, but some additional rain chances may arrive there this weekend or next week.
  • A second system, perhaps very similar to PTC #1 will track toward the Bay of Campeche Sunday or next week, bringing additional heavy rain chances into Mexico and/or Texas.

PTC #1 brings the rain tonight and tomorrow to Mexico and Texas

Late yesterday, Invest 91L was given the tag Potential Tropical Cyclone #1. Why? The National Hurricane Center needed to issue watches for a system that had not yet developed into a technical surface low and had winds of tropical storm strength. Basically, it’s their way of saying “We need to alert on this storm, but it hasn’t met meteorological criteria for formation yet.” From an impacts and what you experience on the ground standpoint, little has changed since yesterday.

PTC #1 is expected to become a tropical storm tonight or tomorrow before scooting ashore in northern Mexico. Impacts from PTC 1 will extend far from the storm with low-end tropical storm force winds, rough seas, and torrential rain in the northwest Gulf of Mexico. (NOAA NHC)

We still expect this system to move ashore in northern Mexico sometime tomorrow evening. It will deliver a variety of impacts to Mexico and Texas, including coastal flooding (also in parts of SW Louisiana), rough seas, and gusty (but likely not damaging) winds. Scattered power outages in South Texas can’t be entirely ruled out, but they would likely not be severe.

Moderate to locally major coastal flooding is expected between Cameron, LA and South Padre Island, TX with onshore winds and rough seas elevating tides, likely closing some roads and causing some isolated property impacts. (NWS Corpus Christi)

But the main thing I think to watch with this system will be the rain. Rain will push ashore in Texas and Louisiana later today and later tonight to the south into Mexico. Based on what we see on modeling and satellite this morning, it would seem that the heaviest rains will take aim to the south of Houston, more toward Matagorda Bay and eventually Corpus Christi.

A satellite image from late Tuesday morning shows deeper moisture offshore of Texas, aimed toward the middle and southern coast, particularly from near Matagorda Bay and southward. (College of DuPage)

And indeed, this seems to be where modeling is rather consistently now focusing the heavier rain chances tonight and Wednesday. You can see from the rainfall map below that we’re expecting anywhere from 2 to 4 inches in the Houston area to 6 to 10 inches near Corpus Christi. I included the plus sign in my annotation on the map because the reality is that there will likely be embedded higher amounts anywhere in the entire region, depending on exactly where any banding features setup, a forecast that’s impossible to pin down more than a couple hours in advance.

Rain totals will peak on the middle Texas coast with anywhere from 6 to 10 inches and locally higher amounts from just south of Corpus Christi up through Matagorda Bay. (NOAA)

Flood Watches are in effect for the entire Texas coast, RGV, and South Texas. Most of this rain will be welcome in interior Texas, where it has been quite dry. The rain in Mexico will hopefully be manageable, but as always in the mountains, we’ll need to watch for mudslides. Some fairly intense rain is also possible on the southern periphery of PTC 1’s circulation, delivering heavy rain to Central America, including 16 to 20 inches (400 to 500 mm) to portions of El Salvador and Honduras.

Significant rain is likely for Central America as well, with portions of Nicaragua, Honduras, El Salvador, and Guatemala seeing impressive totals. (NOAA)

Travel tomorrow may be difficult across South Texas, so expect to run into delays or flooded roads. Conditions will improve a bit on Thursday and especially Friday. For the latest on Houston conditions, visit our Space City Weather site.

Southwest Atlantic system

Meanwhile, we continue to keep tabs on the disturbance in the Atlantic that the NHC gives about a 20 percent chance of developing over the next week. This one is likely to be a nothingburger for the Southeast and Florida and may just serve to elevate rain chances a bit this weekend or next week.

Southwest Gulf of Mexico: Take two

As we see PTC 1 exit late this week, quieter weather will build into the Texas and Mexico coasts, with just some isolated to scattered daily thunderstorms. But then by later in the weekend or early next week, we may get almost a carbon copy of this system: Likely lower-end in intensity, moisture-laden, and tracking toward northern Mexico. The problem will again be rainfall I think. While much of the rain from PTC 1 is welcome and will soak in, if a second system follows suit, the math gets a little more challenging.

Heavy rain is possible again, as you can see from rainfall anomalies between Saturday and Friday of next week on the GFS ensemble. (Tropical Tidbits)

Currently, the heaviest rain is expected to fall just south of where PTC 1’s rains will hit hardest. However, it is far enough out in time and with enough uncertainty to think that we will see things change with this. Interests along the lower Texas coast and in Mexico will want to monitor the next system’s progress closely, particularly with respect to the rainfall outlook. We’ll keep you posted.

Elsewhere, things look fairly quiet with no other systems of note at this time.

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South Texas flooding risks increase this week as near record amounts of atmospheric moisture plow ashore

As of Tuesday Noon, a new post has been updated: Potential Tropical Cyclone 1 will potentially bring flash flooding to South Texas and Mexico – The Eyewall

Headlines

  • A developing flash flood threat will occur in Texas this week, with heavy rain between Houston and Brownsville. Heaviest rains seem likely between Matagorda Bay and Corpus Christi.
  • Invest 91L in the Bay of Campeche continues to show signs that it will develop into a lower-end system before coming ashore in northeast Mexico midweek.
  • An Atlantic disturbance may approach the Southeast coast later this week, with low odds of lower-end development.
  • An additional system or large area of rainfall may impact Texas and Mexico again next week.

Texas axis and Invest 91L

The focus for this week will be very much on Texas and Mexico as impacts from a combination of a long axis of atmospheric moisture and a possible Bay of Campeche tropical system work to deliver heavy rainfall to parts of the region.

The current rainfall forecast as of Monday morning for the upcoming week. Most of this will fall Tuesday night through Thursday morning. (Pivotal Weather)

The rainfall forecast for this system will be tricky. Much like was witnessed in Florida last week, plentiful amounts of moisture in the atmosphere will lead to efficient (read: heavy) rainfall production. Put simply? The potential for some very high rain rates will be in play for the entire Texas coast this week. While the amounts above are a good average for the period, there will almost certainly be higher amounts in spots.

The amount of moisture available in the atmosphere on Wednesday will be near record levels on much of the Texas coast. (Tomer Burg)

The biggest question we are faced with as forecasters is where those higher totals will occur. All weekend, we’ve seen some changes here and there in terms of where the “bullseye” of heavy rain will occur. In general, it looks focused on the Matagorda Bay region south into Corpus Christi, with locally heavy rain but gradually decreasing totals on either side of that. Given the moisture situation, we could easily see 10 to 15 inches in the most persistent bands, possible anywhere, but again most likely between Matagorda and Corpus Christi. Flash flooding will be a good bet in those areas, so please travel cautiously in coastal Texas this week.

In addition, coastal Mexico and the mountains south of the Rio Grande will likely see elevated totals, perhaps as high as 10 inches or so. Flash flooding is a good bet in parts of Tamaulipas and Nuevo Leon.

Conditions should gradually improve Thursday and Friday. Quick note: We are getting a lot of questions about vacation plans, flights, etc. We can’t get to all of those, so just use your best judgment and heed the advice of local officials around your travel. Prepare for at least some delays the next couple days.

In terms of tropical development, Invest 91L is what’s spinning in the Bay of Campeche and has a 70 percent chance of developing into a tropical system. Hurricane hunters will be out to investigate the system later today.

Invest 91L has a broad circulation associated with it over the Bay of Campeche. We’ll see what data is snatched up this afternoon when it’s investigated by the Hurricane Hunters. (Tropical Tidbits)

It seems that 91L has a broad circulation overall, mostly in the mid-levels of the atmosphere. To get declared as a tropical system, we’ll need a low-level circulation and low pressure at the surface. It’s got a little time to do this before it nudges inland over northeast Mexico midweek. Regardless of development, the broad southeast flow to the north side of it will help amplify the rain chances in South Texas and northern Mexico.

Southwest Atlantic rumblings

A disturbance sitting north of Puerto Rico will continue to backpedal to the west over the next few days, eventually approaching the Southeast U.S. coast by Friday or Saturday. It has about a 30 percent chance of developing right now, which seems reasonable given the amount of wind shear it will likely experience in the days ahead.

As the Atlantic disturbance tracks toward the Southeast coast, it is likely to run into a fair bit of wind shear that will likely serve to cap development and intensity chances. (University of Wisconsin CIMSS)

This remains an area to keep watching, but given the setup, it also seems likely that this will have a fairly low ceiling in terms of intensity and organization. The best guess for track would be toward Georgia or South Carolina, with perhaps some added rain up that way later this week.

Texas & Mexico rinse and repeat?

We continue to also keep tabs on the potential for a follow-up round of rain and low-end tropical development next week off the Gulf Coast. Models continue to indicate continued Central American gyre activity near the Yucatan and Bay of Campeche. The pattern will finally break down later next week, with high pressure likely building into the Gulf of Mexico. But before that happens, we could see another disturbance associated with the CAG begin to track into Mexico or South Texas. This shows up nicely when you look at the “spin” in the mid-levels of the atmosphere as forecast by the European ensemble model between this weekend and next Thursday below.

As the Central American gyre begins to get displaced and breaks down next week, one more round of heavy rain may get forced ashore on the Texas or Mexico coasts. (Tropical Tidbits)

It’s far too soon to figure out exact details here. But what we see: A CAG that begins to move and break down, the potential of a tropical system forming within that mess, and a strong signal for above normal rainfall, if not much above normal rainfall again next week in Mexico and South Texas. We’ll continue to watch this closely, especially after one round of heavy rain this week.

Western Gulf Coast to get soaked from major moisture plume as potential new system moves toward Florida

A happy Father’s Day to those celebrating today! We’re here on Sunday with the latest for you on what continues to be an active June in terms of impacts.

Headlines

  • Tropical development is very possible in the Bay of Campeche this week.
  • Regardless, the pattern supports a very heavy rainfall threat for the Texas and Louisiana coasts into Mexico as well, with flash flooding becoming increasingly likely.
  • A new disturbance may track toward Florida late in the week, but most impacts should be north of the areas worst impacted by last week’s rains.
  • Another western Gulf system is possible after this week with more rain in Texas.

Potential for widespread heavy rain and flooding in coastal Texas

The main story from an impacts perspective this week will almost certainly be the situation in the western Gulf of Mexico. We are still monitoring the potential for development from a system in the Bay of Campeche this week.

The National Hurricane Center continues moderate odds (60%) for development this week in the Bay of Campeche. (NOAA NHC)

The chances are fairly modest still, up to around 60 percent, and it would appear that any development should have a pretty low ceiling for intensity. The system should be inland over Mexico by Wednesday or early Thursday.

European ensemble members show a likely track of whatever forms in the Bay of Campeche to be toward the coast of Mexico and inland by later Wednesday or early Thursday. (Weathernerds.org)

The problem is that the overall pattern into the western Gulf remains extremely favorable for heavy rainfall over a very wide area. Extremely deep tropical moisture will be pushing in over top of the tropical low that moves into Mexico. This will crash into Texas on Tuesday and especially Wednesday. The forecast for precipitable water, or the amount of moisture available in the atmosphere will be running near both daily historical maxes and potentially all-time record levels for the Texas Coastal Bend. This means that rain will be efficient and heavy.

Rain totals over the next 7 days will potentially exceed a foot on the Texas coast, with lesser but still hefty amounts possible inland. Flash flooding is likely in spots and at times, especially Tuesday night and Wednesday when most of this falls. (Pivotal Weather)

Rain totals have been escalating all weekend and it now appears that perhaps a foot or more rain may fall on the Texas coast. Lesser amounts are likely inland, but they will still be heavy, and it cannot be stated more plainly that flash flooding and potentially serious flash flooding is possible anywhere between Beaumont and Brownsville, depending on exactly where the heaviest rainfall orients.

The Weather Prediction Center has already highlighted the Texas and western Louisiana coasts for a moderate risk (level 3/4) of heavy rainfall on Tuesday. (NOAA WPC)

A moderate risk (level 3/4) of excessive rainfall and flooding is already in place for portions of Texas and Louisiana on Tuesday, including Houston, Galveston, and Beaumont. Suffice to say, this is yet another example of potentially a low-end storm or nameless storm that can produce significant rain and flooding impacts. Folks in Texas and southwest Louisiana should monitor forecast developments closely today and tomorrow. Stick with Space City Weather for those in Houston for the latest.

A new disturbance tracks toward Florida or the Southeast this week

We left you on Friday with the idea that the focus would move to the western Gulf. What has changed since Friday is that a new tropical disturbance seems likely to form north of the Bahamas by Tuesday. The good news is that this will quickly track west, arriving in or near Florida by Thursday and eventually inland through the Southeast.

A new tropical disturbance will likely form north of the Bahamas and track toward Florida this week. (Tropical Tidbits)

The NHC has a 30 percent chance of development with this one as it tracks west. It would seem that whatever forms will probably be lower-end in nature, but given the amount of rain that recently fell in Florida we’ll obviously want to watch this closely. At present, most model guidance seems to favor it tracking toward areas north of the Space Coast. In that case, South Florida will be fine, with most heavier rain falling toward Jacksonville, Georgia, or South Carolina. As always, it will be good to monitor things the next couple days just to make sure everything behaves with this one.

Beyond this week

It still appears that another system may try to form, spiraling around the Central American gyre next week. Details remain uncertain, but it’s pretty evident that modeling supports a continued rainy pattern in Texas.

Rainfall of 200 to 500 percent of normal is likely on the Texas coast next week as well, which could further exacerbate flooding issues. (StormVista Weather Models)

Both the GFS and European ensemble members shown above indicate agreement on about 200 to 500 percent of normal rainfall for the 8 to 14 day period. This would be 1 to 2 inches more rainfall than usual, on average. So we’ll need to continue monitoring Texas and Louisiana for potential flooding concerns into next week too.

Outside of the western Gulf it looks quiet, and hopefully that area will begin to quiet down a bit too after next week.