Hurricane Nicholas made landfall at 12:30 am Tuesday on the eastern part of Matagorda Peninsula, about 10 miles west of the small city of Sargent. It had maximum winds of 75 mph at landfall. The storm is moving about 10 mph to the north-northeast, and along this track the storm should pass almost directly overhead Houston on Tuesday after sunrise. After that it should turn more to the northeast.

Winds

We’re starting to see wind gusts above 60 mph along the coast of Galveston Island, and we expect to see gusts in the 40s and 50s spreading inland over night. So far power outages in coastal counties range from about 90 percent of customers out in Matagorda County, closest to Nicholas, to about 20 percent in Brazoria County, to 10 percent in Galveston County. Further inland, Wharton and Austin counties have significant outages. More can be expected as Nicholas moves closer to Houston and Harris County this morning.

Rains

So far tonight we’ve seen a thick band of rain showers moving inland from Nicholas, and while the rains have been heavy they have not been excessively so. These rates of generally less than 2 inches per hour are helping to moderate totals. Overall accumulations through Tuesday should be 2 to 8 inches for coastal counties near Houston, with potentially more rain east near Beaumont as Nicholas tracks inland and slows down. Here is the latest rain accumulation forecast from NOAA for now through Wednesday morning.

For the Houston area, it’s likely that the heavier rainfall will wind down between sunrise and noon on Tuesday, with lesser chances afterward. Winds should die down as well. A sense of normalcy should return to our weather by Tuesday afternoon.

“Dirty” side of the storm

We often talk about the “dirty” side of a hurricane, which is located to the right of a storm’s center. This is where the strongest winds, rains, and surge typically lie. And this evening as Nicholas was moving into the Texas coast, its radar signature provided a textbook example of all the activity falling on the east side of the storm, with virtually nothing occurring to the west of the center.

Matt will have our next update by or before 5:30 am CT.

‘Twas the night before Tuesday, when all through the city
None were stirring, not even Harry Styles more’s the pity;
Dry stockings were hung by the chimney with care,
In hopes that St. Nicholas soon would not be there.

Alas, Nicholas is here. And he’s bringing lumps of coal for all. So we’d better discuss the forecast.

As of 10 pm CT, the National Hurricane Center says Nicholas has become a hurricane with 75-mph winds. Its center is presently located 20 miles southeast of Matagorda, Texas. The storm is moving to the north-northeast at 10 mph, and should come ashore the upper Texas coast later tonight, possibly near Sargent, Texas. No additional strengthening is anticipated, the hurricane center says. The storm is expected to cross the Houston region on Tuesday morning and then move into southeastern Louisiana and essentially stall before dissipating by Thursday or so.

Houston area rainfall

Our overall rainfall forecast remains largely unchanged. If you live inland of Highway 59 and Interstate 10, you’re very likely to miss out on heavy rainfall overnight and into Tuesday morning. My expectation would be for 2 inches, or less. If you live closer to the coast, particularly in Brazoria, Galveston, and Chambers counties, heavy rainfall is much more likely. Widespread totals of 4 to 8 inches are likely, with bullseyes of 10 inches or more that may produce localized flooding.

The radar image below tells the tale of the night. We can see the main band of thunderstorms along the Texas coast, but mostly offshore. This band of gnarly storms will to move to the northeast tonight, and how bad things get for the Texas coast will depend on how far inland it gets (or how far offshore it remains). Right now I’d be surprised if the heaviest rains pushed much farther inland than League City tonight. But we’ll see. I’ve also annotated the line where there’s no rain now. There probably won’t be much precipitation west and north of this line tonight, either, as Nicholas moves to the northeast.

As this system slogs toward the northeast over night, it will have the potential to drop rainfall across all Texas coastal areas. However, for now, it appears the heaviest rains will come over Galveston and Chambers counties, with lesser amounts further east, including the Beaumont and Port Arthur areas on Tuesday morning.

Wind and power outages

For inland counties, including Fort Bend and a majority of Harris County, this now appears more likely to be a wind storm rather than one of significant rains. As of 9:30pm about three quarters of Matagorda County were experiencing power outages as Nicholas battered its shores with hurricane-force wind gusts. These winds, although diminished, should spread inland over the next several hours. I’d expect at least scattered outages as trees fall into power lines.

When does this mess end?

Our confidence in when the heaviest rains from Nicholas push east of Houston remains middling, but I’d expect rains in Galveston County to wind down around sunrise or mid-morning.

Our next update will come at around 1 am CT.

Good evening. Tropical Storm Nicholas is nearing the middle Texas coast and should make landfall near Matagorda Bay within several hours. The storm’s maximum winds increased to 65 mph this afternoon, and it’s quite possible Nicholas will become a Category 1 landfall before landfall tonight. Wind gusts from Nicholas are starting to arrive along the upper Texas coast, and should peak around midnight or during the wee hours of Tuesday.

As Nicholas nears the shore we are starting to get more confidence in rainfall forecasts for tonight and Tuesday morning as the heaviest rains from the storm move through. And as a result of this we are lowering our Flood Stage alert for all but coastal counties.

As you can see on the (very professionally drawn) map above, we are keeping a Stage 3 alert for coastal counties, Stage 2 for the next tier, and Stage 1 for areas northwest of Houston. Basically, if you live near the coast, an additional 6 to 12 inches of rain is possible tonight, with higher localized totals. For areas roughly along Interstate 10, values should be about half of this, give or take. And for areas well inland, overall accumulations will likely be 3 inches or less. As a reminder here’s what our various flood scale alerts mean:

Timing of events

The overall pattern for events tonight should not change a whole lot. Heavy rainfall will advance from the southwest into the Houston region tonight, likely reaching a corridor from I-45 South to downtown Houston around midnight, or an hour or two later. These storms will then continue to push to the northeast, perhaps moving away from Harris County by around sunrise or mid-morning.

Maximum wind gusts of 50 to 60 mph will likely move into Brazoria and Fort Bend counties by late evening, with gusts in the 40s reaching Harris County by around midnight. These winds should begin to weaken by around sunrise on Tuesday morning. Expect scattered power outages, at least, as trees and debris fall into power lines.

We think conditions may begin to improve across the area by around sunrise on Tuesday, or perhaps mid-morning. So our advice is to not have any concrete plans for Tuesday morning, as we cannot say a whole lot about conditions with confidence. By Tuesday afternoon we expect conditions to improve markedly. At this point we think Wednesday should see a return to normal activities across the region without too much difficulty, and excluding any areas that saw widespread flooding on Monday night.

Our next post will come by around 10 pm to fine-tune the forecast for tonight and Tuesday.

Good afternoon. Much of Houston is seeing a reprieve from storms after a band of showers moved through the region around noon. It looks as if rain showers will remain somewhat scattered and non-threatening through the late afternoon or early evening hours. The main event is still offshore, and will reach our region later tonight.

Speaking of the main threat, Tropical Storm Nicholas retains 60 mph winds as of 1 pm CT, and continues to move north toward the Texas coast. It likely will make landfall near Matagorda Bay later this evening. The storm covers nearly all of the western Gulf of Mexico this afternoon.

Throughout the day, we’ve been getting our first inputs from high-resolution models about rain accumulations tonight and on Tuesday for the Houston metro area. The early returns suggest that most of Houston may fare pretty OK from rain dropped by Nicholas. We still have some very serious concerns, however. Let’s discuss.

Our confidence is increasing that a line of storms associated with the core of Nicholas will move into our region from the southwest tonight. It looks like these storms will reach Brazoria County around midnight, or shortly thereafter. Then they should progress toward downtown and the I-45 South corridor some time after midnight and before 6am CT on Tuesday. This is a little slower than previously anticipated, and may give Houston residents a few hours after sunset this evening before roadway conditions deteriorate. (Gusty winds will probably also arrive in Harris County around midnight, or after).

The other major shift we’ve seen in some of the model guidance is that the threat for heavy rainfall is becoming more concentrated along the coast, in places like Brazoria, Galveston, and Chambers counties as well as the Clear Lake area of Harris County. If this forecast holds, areas inland of Interstate 10 may see only a couple of inches tonight, whereas the coast will face a higher threat of 5 to 15 inches. One of our big questions right now is whether the heaviest precipitation falls offshore, or along the coast in places like Matagorda, Sargent, Freeport, and Galveston Island.

Matt and I have discussed this quite a bit this afternoon, and for now we’re holding to a Stage 3 flood scale warning for the entire Houston metro area. But that probably oversells the threat to locations north of Interstate 10. We’re going to continue to look at more data and decide whether to reduce our flood scale warning later today. We’ll leave you with this: It’s OK to have some hope about the Nicholas forecast, but we still have a lot of questions and a very explosive, tropical air mass headed this way.

Our next update will come at 6 p.m.