Posted by Eric Berger at 4:10 PM
A solid round of showers and thunderstorms rolled through Houston on Monday during the daytime, dropping 0.5 to 2.0 inches of rain for most of the area. It now seems likely that the radar will quiet down for most of this evening, before heavier showers being to develop along the coast on Tuesday morning like on Monday morning. The National Weather Service has prudently kept a Flash Flood Watch in place for coastal counties, and the inland tier including Harris County, through noon Tuesday (Note: after this post was published Monday afternoon, the flood watch was extended until 6pm CT Tuesday. Our forecast remains unchanged.) The best hope is that the heaviest precipitation stays just offshore, rather than migrating on shore during the next 24 hours or so.
Area of flash flood watch. (National Weather Service)
Unfortunately, rain chances are not going to go away on Wednesday and Thursday. Although rain showers should be more scattered in nature, and perhaps less intense, we definitely can’t rule out locally heavy rainfall due to the tropical air mass and overall stagnant pattern. Given all of this, we expect accumulations of 1 to 3 inches for inland areas from now through Thursday, with 2 to 5 inches more likely for areas immediately along the coast (with higher isolated totals). The primary threat should be street flooding rather than significant stream and bayou flooding.
Posted by Eric Berger at 6:41 AM
Man, I hate this time of year. Invariably, the tropics reach their crescendo, and this year is no different. In fact, this is only the 11th time on record that three hurricanes have been active in the Atlantic simultaneously, Florence, Helene, and Isaac. This week, Hurricane Florence will rightly suck up a lot of the national oxygen—Matt did a commendable job of summarizing the risks to the Carolinas and beyond, and they are tremendous in terms of flooding, wind, and surge—but we have some homegrown threats to consider as well.
Tropics as of 7am CT on Monday. (National Hurricane Center)
For this post we are going to focus on the near-term threat of heavy rainfall on Monday and Tuesday, and then the late-week threat from a nascent tropical system. Did I mention that I hate this time of year?
Monday and Tuesday flood watch
The National Weather Service has issued a Flash Flood Watch for the coastal and inland tier of counties for 1pm Monday through Tuesday morning, and they admit they may have to extend it. Basically, we have a lot of low pressure hanging around and a super-moist atmosphere. I think at best we can hope for scattered, heavy rain showers; and at worst we probably will see some spots of 3 to 6 inches over the next two days. Most likely the hardest hit areas will be along the coast, and if we’re lucky the heaviest rains will fall offshore.
Area of flash flood warning in effect through Tuesday morning. (National Weather Service)
Both Monday, Monday night, and Tuesday will probably be similar in this regard. We’ll just have to watch radar trends and if you have to drive for more than a short errand, you should probably check road conditions at your destination. This shouldn’t be anything more than street flooding, but we can’t guarantee that.
Posted by Eric Berger at 5:22 AM
Houston will have another day of somewhat drier weather before a wetter pattern returns to the region through Monday. Yes, another soggy weekend. Sorry about that. Also, while we’re on the subject of bad news, if you’re wondering when fall’s first front might arrive, I’m afraid there just aren’t any really strong signals for that right now. I would not anticipate it coming before around Sept. 20, if then.
The region should see some partly sunny skies today, so enjoy the sunshine while you can. Some isolated to scattered showers will be possible, but for the most part it should be a dry day. More sunshine will mean higher temperatures, so we can probably expect low 90s for most of Houston, with a smattering of mid-90s possible.
Friday, Saturday, Sunday, and Monday
Unfortunately, the pattern for this weekend looks wet, with low pressure in place overhead and a plenty moist atmosphere. Effectively this means that most areas of Houston (50 to 70 percent) will see rain on most days from Friday through Monday. Although the forecast models aren’t forecasting any rain bombs at this time that might lead to some street flooding, with this kind of atmosphere during the summer months we can’t rule out some heavier showers that temporarily clog streets.
Temperatures, as usual, will depend upon the extent of cloud cover and rainfall. Look for a range from the mid-80s to lower-90s. Humidity, of course, is guaranteed.
Posted by Eric Berger at 5:26 AM
September has been a wet mess for most of Houston, but the one upside has been temperatures. At a time when we typically see highs in the mid-90s, the last three days have generally produced highs in the 80s. And if you like this wet, slightly cooler than normal pattern have we got a deal for you. Because this rain-lovers-delight pattern should continue for quite awhile.
Wednesday and Thursday
These days should be drier than the recent weather in Houston, but only in the sense that showers and thunderstorms should be more of a scattered nature rather than widespread. Even so, we expect 30 to 50 percent of the region to see some form of rain the next two days. Highs will depend upon shower activity, and likely will range from the upper 80s to the lower 90s. Sunshine will be scarce, but we can probably reasonably hope for a few breaks in the clouds.
The NOAA rain accumulation forecast for now through next Tuesday looks healthy, but not extreme. (Pivotal Weather)
Friday, Saturday, and Sunday
As whatever is left of Tropical Storm Gordon moves well north of Houston, toward Oklahoma, it will leave lower pressures in its wake for our region. This will lead to, again, a healthy chance of rain showers through the weekend, probably around 60 percent each day, give or take. This should keep highs in the 80s or low 90s, and unfortunately we’re going to hold onto those mostly cloudy skies. If you’re planning outdoor activities, uhhh, have a back-up plan.