Matt Lanza

As Eric has been alluding to all week, things have now changed, and they will continue to do so in a big way for not just Houston but all of Texas. Last evening’s rowdy (and in some cases damaging) storms were the first phase in what will be a much different weather pattern for the rest of the month. The Texas-wide drought is on notice for what should be significant relief.

Today

We’re starting the morning off with some noisy storms south of Houston. The storms are generally moving east, but the overall trend seems to be to build storms back to the north some. None are severe at this point, but there are some special marine warnings on the coast due to 35 to 45 mph wind gusts, or a bit stronger, as well as the potential for waterspouts.

As the day goes on, storms should continue expanding northward and inland. Locally heavy rain is again possible today. Thus far, rates are fairly manageable, but a few spots may need to be watched today for some street flooding. Most of Southeast Texas has been outlined in a marginal (Level 2/4) risk for flash flooding today. As a precaution, we are going to issue a Stage 1 Flood Alert, based on the SCW Flood Scale.

Street flooding is possible anywhere in the area today, but I would watch areas west of Houston that saw 2 to 3 inches of rain yesterday, as well as areas south of Houston, where the heaviest rain is right now. Yes, this is welcome rain to be sure, but some nuisance street flooding feels possible today, especially through early afternoon.

Storms should calm down by evening. Clouds and showers will keep temperatures down today. Highs should only be in the 80s, though if you see sunshine in your location, you could pop above 90, especially north and west of Houston.

Invest 99L & weekend

The weekend forecast will be hit and miss for most folks. At this point, I think both Saturday and Sunday carry a good chance of at least scattered showers or storms, near the coast in the morning, expanding inland during the afternoon. Locally heavy rain is possible, but widespread heavy rain seems unlikely this weekend. Both days should see some sunshine, which will allow us to punch back into the 90s in most spots, with morning lows in the 70s.

Regarding the tropics, the National Hurricane Center continues to highlight the potential for now-classified Invest 99L to become a tropical depression or storm over the next 24 hours before moving inland over Mexico on Saturday.

This should have no direct impact on our weather in the Houston area, but it’s possible that some heavier rains get close to South Texas later in the weekend or early next week.

Next week

I am not going to even try to pin down the specifics of any day next week. What we know is that there will be rain chances every day. Some of the rain could be heavy. Parts of the state are going to see a lot of rain (see below), probably to the north or northwest of the Houston area. Daytime highs will flirt with 90 every day, but days that see more widespread showers or storms will probably stay in the 80s. Humidity will stay high, so nighttime lows well into the 70s are still likely.

Rain totals

So just how much rain will Texas see over the next week or so? The answer is a lot. The current NWS outlook for rainfall across Texas is below and shows as much as 7 to 8 inches in interior Texas, including the DFW area and possibly the Austin and San Antonio areas as well. Higher amounts are possible, as is flooding across the state.

While the Houston area should see a bit less than other parts of the state, there’s still enough uncertainty in the forecast to think we have a chance at higher amounts, especially north and west of the city. Whatever the specifics, this is a big, big drought denter for the entire state of Texas. We’ll keep you posted as needed over the next few days.

After a summer of fishing for things to talk about in each week’s Eye on the Tropics, we’re quickly transitioning into peak season now, with a number of things to discuss. Today’s post will explain one system that should bring us some boosted rain chances heading into the weekend or next week, the chance of activity in the Atlantic, and what the pattern change expected over Texas will mean for us in terms of tropical risks.

Tropical outlook in a sentence

Activity should begin to ramp up this weekend and next week with a possible weak system in the Bay of Campeche, followed up by some additional tropical waves in the pipeline across the Atlantic worth watching.

Bay of Campeche & south Texas

This weekend saw tremendously beneficial rains in far south Texas. There may be more coming but who sees them remains a question. A tropical wave located over the southwest Caribbean is expected to move generally northwest over the next few days.

The National Hurricane Center is giving this about a 20% chance of developing into a depression or storm over the next 2 to 5 days. While a lot of folks will see this and be alarmed, there are reasons to think this system will struggle in terms of organization. For one, while wind shear was low in the Gulf as Invest 98L came crashing ashore on Sunday, wind shear in the western Caribbean and Bay of Campeche is not low. It’s fairly robust, and based on most model data I’ve looked at, some elements of shear are going to persist around this system until it comes ashore. My hope is that this will cap the ceiling on intensity potential.

The other reason not to really worry is that the pattern is going to likely keep it from coming up the Texas coast. It will track toward northern Mexico or the Rio Grande Valley as a disorganized tropical low, depression, or low-end storm. No credible modeling shows anything worse than that right now.

While South Texas saw a heck of a lot of rain from Invest 98L, where the rain falls this time around will be a little trickier to project. If the system can organize some, heavier rain is possible again in South Texas, while scattered storms would impact the Houston area at times. If the system remains rather disorganized, it’s possible that South Texas will see limited rain, but the bulk of the moisture coming from this wave will end up entrained in a cold front stalled over north Texas, bringing heavier rain to the Panhandle, DFW area, and into northern Louisiana and Arkansas. In that case, again Houston would see just scattered storms.

So for now, while I wouldn’t worry about this one specifically, I would continue monitoring it to see how rain chances will evolve.

Atlantic waves

Behind this wave, there are a few others in the deeper Atlantic.

Modeling is showing a lot more noise in the Atlantic from these waves now, meaning more ensemble model members are developing some of them. However, there’s not a whole lot of signal in the noise. That’s both good news and bad news. It’s bad because it doesn’t give us anything to hone in on just yet. So, all we can say is “Hey, the tropics are going to be active in late August.” Bold statement! But it’s good because there’s always a chance that the lack of signal indicates the environment will remain somewhat hostile toward tropical development. We’ll continue watching this to see if there’s anything to latch onto in the coming days, but as of now there’s nothing to hang our hats on.

Does the pattern change mean a change in Texas’s tropics risk?

We’ll close today’s note with a quick comment about the big picture pattern. For most of summer, Texas has been shielded by high pressure over the southern Plains and Central United States. This is why June and July were so hot.

That high pressure system acted to basically keep us hot, dry, and protected from any Gulf threats all season. The pattern is changing now, rather dramatically. The new look will feature high pressure mostly anchored in the northern Rockies or western Canada, as well as near Bermuda, with a rather healthy trough in the Eastern United States.

This means a couple things. For one, we’re no longer really “shielded” from the Gulf. So anything that can get into the Gulf will be apt to gain a bit more latitude than it would have back in June, July, or early August. That certainly doesn’t guarantee that we’re at risk for storms, but it has made us more vulnerable. That said, the other element to this is that the trough in the East *may* act to help “pick up” Atlantic systems more easily. In other words, the stuff coming off Africa may be more likely to get lifted north earlier, which favors either out to sea tracks or up the East Coast tracks. So our focus would probably be less on long-tracking storms from Africa and remain on systems like 98L, this week’s system coming out of the Caribbean, or anything that can spin up on the tail end of old fronts. So, this is a good news/bad news sort of scenario for us. The key points I want you take away from this post today are:

• The tropics are finally coming alive, as is usually the case in late August.
• The main system to watch right now, a tropical wave in the Caribbean, will likely track toward far south Texas or Mexico this weekend and increase our rain chances some.
• Additional waves have the potential to develop farther out in the Atlantic next week, but none looks like a slam dunk just yet.
• The general pattern change we will see in Texas is going to leave us open to local, “homebrew” Gulf threats, but there is a chance that the pattern in the Eastern U.S. will favor deep Atlantic systems turning out to sea or perhaps getting closer to the East Coast.
• With the season ramping up now, it’s time to start checking in once each day or two to see what’s happening and make your final checks on emergency kits and plans while we grind through things into September.

This may or may not be our last weekly post on the tropics, as we may have enough to discuss daily now. Regardless, stay with us for updates on anything of note in the days ahead.

Invest 98L, the tropical disturbance we’ve been watching over the Gulf the last couple days, is now ashore in South Texas, ending any potential development concerns. And it’s probably a good thing, as the disturbance finally starting organizing more rapidly overnight and this morning.

Another 12 to 24 hours over water probably would have led to a formidable named storm. Thankfully, that isn’t the case, and the steady march westward of 98L will continue through the day. For our neighbors to the south, this is about as good an outcome as you could ever ask for: Widespread drought-easing tropical rains without the damaging impacts of a strong tropical storm or hurricane.

Additional rains will add up to about 1 to 4 inches, maybe a bit more in some spots in far south Texas or northern Mexico. Flash flooding is definitely a possibility in spots, but in most cases, it should be brief and manageable. More importantly, reservoirs and rivers in that region will get a boost.

Houston weather

For the Houston area, 98L’s last minute organization really robbed us of moisture to work with initially. As winds turn back onshore today, we should see a slight bump up in shower activity leading to more scattered action. The highest odds of rain will be near Matagorda Bay, with the lowest odds northeast of Houston. Still, there will be scattered showers around anywhere today, and even if your neighborhood will probably remain dry, it will be good to take an umbrella with you if you’ll be out and about. Highs into the mid-90s, cooler south, hotter inland.

Rain chances drop off substantially Monday, Tuesday, and Wednesday. Look for a return to upper-90s, if not 100 degrees in much of our area to start the upcoming week. Better rain chances are still on target to return Thursday or Friday, as a generally wetter, cooler pattern tries to establish over Texas. I don’t want to overstate anything, but modeling continues to strongly argue for a bonafide pattern change in Texas heading into and beyond next weekend. Eric will have more for you tomorrow morning.

Friday saw some very scattered rain across the area. Most inland areas got nothing, but a few spots picked up a half-inch to an inch or so. A few areas around Galveston Bay and along the coast saw a bit more. That refrain will be with us today, with inland areas mostly escaping storms, but coastal areas seeing the highest odds. This is thanks to Invest 98L, the tropical disturbance off the coast that will be tracking toward the southern part of Texas, keeping most of the rain to our south.

Invest 98L

A look at satellite this morning shows that 98L is spinning away in the Gulf. It remains ill-defined, so any development is not going to happen quickly, and it will almost certainly run out of time to become anything of note before coming ashore.

A reconnaissance aircraft is on the schedule to investigate this system around midday today, if it is still deemed necessary. The three big points from our perspective are:

1.) Any tropical development is going to be low-end and short-lived.

2.) No direct impacts are expected in the Houston area or along the coast north of Freeport.

3.) The primary issue in South Texas (Rio Grande Valley, Brush Country, Corpus Christi) from 98L will be heavy rainfall, mostly beneficial but perhaps enough to produce some flash flooding.

Minor coastal impacts, like some erosion or wave runup are possible from Matagorda Bay south. For Galveston down through Surfside Beach, the water may runup the beach a good bit at high tide but flooding is not expected.

Houston area

With 98L not a direct concern for us, we will be on shower watch today. From downtown Houston to the north and west, minimal shower activity is expected today, with just a handful of downpours possible, much like yesterday. South and east of downtown, the odds of showers are notably higher, but even there it will be mostly just scattered in nature, meaning some folks won’t see rain. Wherever showers do fall, a quick half-inch to inch will be possible. Highs will range from the 80s on the coast to upper-90s inland.

For Sunday, expect much more of the same. Some of Sunday will depend on how organized 98L gets before coming ashore. If it can consolidate most storminess, it may keep most areas, even near the coast dry. If it remains broadly disorganized, scattered showers will be more likely, mainly south and east of downtown Houston. We’ll update you on this tomorrow!

We apologize if you did not receive an email yesterday. We had some technical issues to sort out, and hopefully those are fixed before I press send today!