Just a quick update on Wednesday afternoon to say that our forecast from this morning holds—effects from Tropical Storm Cindy are unlikely to be too significant for the greater Houston area. Mostly, we can expect some heavy rainfall. The only thing that could change this is if the storm follows a westerly track into the Galveston area, but at present that seems to be a low probability.

Rainfall

We’re starting to see some convection firing up on the west and northwest side of Cindy’s center today, but the storm is running out of time to become a real rainmaker for the Houston region as it will near the coast tonight, and move inland by Thursday morning. The water vapor image below shows some of the convection developing out in front of Cindy as the storm moves northwest toward the Texas-Louisiana border.

Water vapor image from early Tuesday afternoon. (US Navy)

Most of the model guidance suggests the Houston region will likely see 1 to 3 inches of rain from Cindy later today, tonight, and on Thursday. Generally, rain chances will be greater to the east of Interstate 45. Given the tropical nature of this system, we can’t rule out some isolated bullseyes of 6 inches, but I think we can confidently say this is likely not going to be a major flooding event for the area.

Average rainfall totals from GFS ensembles for now through Friday. (Weather Bell)

Tides and winds

At present waves are coming up onto Bolivar Peninsula, and seas are rough, but road conditions along the coast are generally manageable. Rip currents are a concern as well. It looks like high tides will reach a maximum of about 4 feet above normal.

In regard to winds, expect some gusts tonight in the upper 20s or low 30s in the city, and possibly in the low 40s along the coast. Sustained winds will be lower.

We’ll keep you posted as conditions change.

Posted by Eric at 1:55pm CT on Wednesday

 

Tropical Storm Cindy began moving again on Tuesday evening, but after strengthening into a 60-mph system it has become a little ragged overnight. Increasing wind shear and dry air have caused the system to look like something less than a tropical storm. This bodes well for the Houston region, as without wrap-around rains the storm seems unlikely to bring the worst—floods and damaging winds—into the area.

Track

Cindy has been moving to the northwest overnight, and models now generally agree that the system will turn north toward the Texas-Louisiana border later today. It should make landfall around midnight tonight, or during the pre-dawn hours Thursday. This would place the greater Houston region on the left side of Cindy tonight and that should make some difference in our weather conditions.

Official forecast track of Tropical Storm Cindy at 4am CT. (National Hurricane Center)

Rainfall

During the last 24 hours Cindy’s northern rain bands have battered the northern Gulf Coast, generally producing 4 to 6 inches of rain across a widespread area along Interstate 10 from Louisiana through the Florida panhandle. More is coming today while the west and southern sides of the storm remain mostly dry. This is due to the asymmetric structure of the storm in which most of the severe weather is north and northeast of the center. Read More…

As most of you probably know, Tropical Storm Cindy formed in the Gulf of Mexico today. This post will assess the storm’s rainmaking potential, and whether high winds or tides will impact the Houston area. I’ll also discuss why I’m becoming a little more concerned about Cindy.

Track

Although Cindy has improved its circulation, it has stalled in the Gulf of Mexico a few hundred miles south of Louisiana. This adds some uncertainty to the landfall location, but I still feel pretty confident that it will be come ashore somewhere between Matagorda and the Texas-Louisiana border. Landfall timing is probably Wednesday night or Thursday morning.

The European model shows a tropical storm coming ashore near Galveston early Thursday. (Weather Bell)

Read More…

(Note: I deeply apologize for Monday evening’s server issues. We are addressing the problem, and should have a permanent fix within place in 24 to 48 hours).

Houston will have one more sunny, hot day on Tuesday—with highs likely in the mid-90s again, and boy did Monday sure feel like summer out there—before our weather becomes affected by a tropical system in the Gulf of Mexico. That will therefore be the focus of today’s post. Please also note that this is a dynamic forecast, and Houston could still see some fairly significant effects from this system based on some of the latest available model data.

Organization

The tropical disturbance appears to slowly be organizing this morning and nearing tropical storm status, but for the purposes of rainmaking, that doesn’t really mean a whole lot. What we often see with storms in the Gulf of Mexico during this time of year, when wind shear is fairly high, is a struggle to get organized and then a strengthening just before landfall. If that happens with this system, I think we can expect a moderate tropical storm coming ashore on Thursday some time. The primary threat remains heavy rainfall.

Water vapor image of storm on Tuesday morning, showing track favored by European model. (US Navy/Space City Weather)

Track

So where is it going? A lot of the track models have shifted closer to the European model, which brings the storm to the upper Texas coast—between Corpus Christi and the Texas-Louisiana border—by Thursday morning or so. As we discussed Monday, the bulk of the rains with this system are well east of the center, so the significant rainfall totals are going to be east of wherever the system comes ashore.

The official track from the National Hurricane Center.

Rainfall

As a best guess, this likely means parts of southeastern Louisiana and Mississippi could see 10 to 12 inches of rain on Wednesday and Thursday. Closer to home, rain totals are really going to depend on landfall location. If the European model is correct, a landfalling storm just south of the Houston area could bring 4 to 6 inches of rainfall to the Houston region beginning some time on Wednesday and running through Thursday (these would be mostly manageable totals, but still very wet days). If the final track is closer to Beaumont—currently favored by the National Hurricane Center—then the Houston area may only see 1 to 2 inches of rainfall, if any at all. Bottom line: This tropical system remains a close call for Houston.

Winds

These will, again, be highly dependent upon the final track. But if the storm comes ashore along the upper Texas coast as I expect, we can expect some blustery days on Wednesday and Thursday, with gusts in the 20s and perhaps 30s along the coast. If the storm strengthens, those values could rise a little bit higher, but I’m not overly concerned about the prospect of wind damage at this time. Should the storm make landfall in Louisiana we’ll still see some winds blowing out of the north, but nothing too significant.

We will update as warranted today.

Posted at 7am CT on Tuesday by Eric

Here’s an afternoon update based upon the latest model guidance for the tropical system, Invest 93L, now located in the southern Gulf of Mexico. A hurricane hunter is investigating the system this afternoon, and it may be upgraded into a depression or storm later today.

It’s best not to think of this system as a classical tropical storm or hurricane, but rather, as my colleague Matt Lanza puts it, “an atmospheric river” of moisture flowing from the south into the United States. In other words, we’re dealing with something that’s going to bring a lot of rain to someone along the Gulf of Mexico coast. Consider the following forecast, from the European model, for precipitable water values on Wednesday night.

Precipitable water values for Wednesday night. (Ryan Maue/Twitter)

Any value above 2 inches of precipitable watyer is quite high, and you can see that although the center of this storm is near the Texas coast, it is funneling a massive amount of moisture from the Gulf of Mexico into Louisiana. That spells a heavy rainfall event.

Read More…