Well, they don’t call them natural disasters for nothing. For some residents, of course, last night was but a breezy affair. For others, especially along the coast, there is substantial wind and flood damage to contend with this morning from Hurricane Nicholas. And then there are the half a million customers in the greater Houston region without power this morning.
For those of you recovering today—and I count myself among you as power went out in my neighborhood, trees are down, my backyard flooded—it may not feel like it, but this storm could have been so so much worse. With this post I want to discuss that, but first lets update the status of Nicholas and present a short-term forecast.
Tropical Storm Nicholas
As of 10am CT, the center of Nicholas is very nearly directly over Houston, located just 10 miles southeast of downtown. As it has moved inland for nearly 10 hours, Nicholas has weakened to a storm with sustained winds of 45 mph. The storm is moving slowly, the northeast, at about 6 mph. It should continue to turn more easterly, and then dissipate over Louisiana in two or three days. The main rainfall threat has moved east, and the southern half of Louisiana could see 6 to 10 inches of rainfall over the next several days.
The forecast for today and Wednesday will allow for recovery in the greater Houston area. Some light, scattered showers will be possible today and Wednesday, but chances are fairly low and accumulations should be slight. The strongest winds, too, have moved east of the area despite the presence of Nicholas’ center.
If you’re without power, high temperatures today will be quite reasonable for this time of year, in the upper 70s. Humidity will be high, of course. Lows tonight will drop into the low 70s. Highs on Wednesday should reach the mid-80s with a mix of sunshine and clouds.
If you want a more hopeful thought, we’re seeing fairly strong hints in the models for a decently strong fall front moving into the region in nine or ten days time. That’s a long way out to forecast, so grain of salt and all that, but it is the right time of year for a front. So maybe, hopefully, fall is but 10 days away. I’m ready.
Nicholas could have been so much worse
First of all, if you can remember all the way back to Saturday, I presented three different scenarios for Nicholas’ track and eventual flooding in Houston. The first of these was the “Coast Hugger,” in which the storm remained close to the Gulf, brought 2 to 4 inches of rain to Houston and higher amounts along the coast, while keeping the heaviest rains offshore. This is largely what happened, with Nicholas remaining very close to the coast even after moving inland. If we look at satellite-derived precipitation totals for the last three days, the heaviest swath of 10-20 inches of rainfall came offshore.
A track even 40 or 50 miles further inland would have set up those heaviest rains directly across the Houston metro area, and created a much more serious flood situation. Hopefully this offers you some insight into the challenge of predicting these kinds of rain events. It was a very close call, a matter of miles, between significant inland rainfall flooding in Houston, and relatively clean bayous this morning.
The second factor is wind. Nicholas turned out to be a fairly nasty storm in terms of wind gusts, and pushed a larger storm surge—as high as 6.1 feet into Clear Lake—than predicted. This is a reminder of the power of a hurricane, even one that was “only” a minimal Category 1 storm. The truth is that the track of the storm was very nearly a worst-case one for Houston in terms of winds and putting a maximum storm surge across Galveston Island and into Galveston Bay.
It is September 14, the absolute peak of hurricane season in the Atlantic, and a time when sea surface temperatures in the Gulf of Mexico are at their warmest of the year. So this morning I’m thinking about what would have happened if we had not had some wind shear over the western Gulf of Mexico yesterday, or if Nicholas had been able to consolidate a more well defined and consistent center of circulation. It would have been much, much worse for all of us had a significantly stronger hurricane made landfall last night. So while we pick up the pieces this morning, realize Nicholas could have been much more of a terror.
Matt will have our next update—and probably our last update specific to Nicholas—at 5 pm CT today.