Posted by Eric Berger at 6:33 AM
The city of Galveston started September with a 12-inch deficit in annual rainfall, and now, a little more than halfway into the month the city has a nearly 5-inch surplus. The last two weeks have been incredibly wet for the island, and the southern half of the Houston region as tropical moisture has surged into the area.
Galveston temperature and rainfall (bottom) plot for 2018. (National Weather Service)
The image below, showing rainfall over the last 14 days, demonstrates how the coastal areas have been inundated, whereas some inland areas have received as little as 1-2 inches. While these rains—in excess of 20 inches for locations along the coast—have caused some flooding problems they have not been too widespread. This is because the region can handle 20 inches of rain over two weeks. It’s the 20 inches of rain in two days that causes major problems.
14-day rainfall totals for the Houston metro area. (NOAA)
While we are not done with rainfall entirely, I think it is safe to say we are likely done with the threatening, heavy tropical rainfall for awhile. Good riddance.
A partly to mostly sunny day today, with only isolated to scattered showers later during the afternoon hours. The sunny skies and lack of precipitation should allow temperatures to nudge up into the mid-90s for most parts of the Houston region. Summer, alas, is not quite ready to loosen its grip.
Posted by Eric Berger at 6:32 AM
Did thunderstorms wake you up? A band of rainfall related to a disorganized tropical disturbance moving into South Texas blew through the Houston region this morning, bringing heavy rains and some really loud thunder cracks. This band has weakened now, but a few more storms will rotate through the area today before the westward moving system clears the area. After this we will see mercifully waning rain chances for awhile.
Looking at the radar, a mass of storms associated with the tropical disturbance can be seen moving steadily westward. However, Houston will remain on the northeastern periphery of the disturbance today, so we can expect to see more showers rotate through. Right now we don’t anticipate anything too extreme, but areas that pick up 1 to 2 inches of rain in an hour can probably expect to see some street flooding, which is most likely for areas between downtown Houston and the coast, and southwest of the city.
(National Weather Service)
The National Weather Service has a flash flood watch in place for coastal counties that expires at Noon today. They may extend it through this evening as a precaution. We can probably expect the heaviest rains to die down by this afternoon or this evening.
Posted by Eric Berger at 6:17 AM
As we’d hoped, the radar has generally been quieter this morning across the Houston area, with showers neither as intense or widespread as they’ve been over the previous two mornings. And while we’re not out of the woods in terms of heavy rain and street flooding potential, we can at least see a period of sunnier weather in the distance.
The southern half of the Houston area remains under a flash flood watch through Thursday evening, and this is primarily because of already saturated grounds due to a very wet week for the coast. Generally, we don’t expect coastal areas to pick up more than an additional 0.5 to 2 inches of rain during the next 24 hours as moisture continues to stream inland. This should be manageable, but we’re definitely watching several bands of stronger showers just offshore that could move inland.
NOAA rain accumulation forecast for now through the weekend. (Pivotal Weather)
Friday and Saturday
The oft-discussed Invest 95L—and there really has been a lot of sound and fury for a tropical system that never really has appeared all that threatening—will continue to move toward the Texas coast, and should come inland Friday. The threat from this storm will be heavy tropical rainfall, but as the system remains disorganized, it shouldn’t be that potent of a rainmaker. Some areas along the Coastal Bend may see upwards of 3 to 5 inches of rain over the next few days with some higher isolated totals, but in the Houston area I expect the coastal areas to hopefully see less than that, and inland areas perhaps 1 inch of rain through Saturday.
Posted by Eric Berger at 4:22 PM
After another wet morning along the coast, the heavier rains have mostly stayed offshore this afternoon. The big question now becomes: Will Thursday morning offer a repeat performance of Tuesday and Wednesday morning super soakers along the coast? We hope not, and we think not. But alas, we are not certain.
The area of the flash flood warning is shown in the hash-marked area. (National Weather Service)
The National Weather Service has issued a flash flood watch for coastal areas that extends from midnight tonight through Thursday evening. The weather service expects an additional widespread 1 to 2 inches with isolated 4 inches of rainfall are possible across the watch area.
This seems about right, but for the most part, we don’t expect quite the punch we’ve seen the last two nights where areas such as Dickinson, League City, and Kemah have seen a total of eight inches. But given the moisture available in the atmosphere we can’t rule it out.
Also of note: We’re continuing to watch Invest 95L, which could become a tropical depression on Thursday in the Gulf of Mexico as it moves toward the southern Texas coast. However, we still don’t anticipate major effects for Houston at this time. That could change, of course. But at this point we’d sooner bet on a partly sunny Sunday than we would on a complete washout this weekend. We’ll be back with a full forecast early tomorrow.