Today marks the autumnal equinox, which means it is the first day of fall. But Houston has felt anything like fall so far this September, as low temperatures have rarely fallen below 75 degrees. The city has yet to see its first real fall cool front—which for the purposes of Houston we define as a daily minimum of 65 degrees or cooler. As you can see on the chart below, the first fall front typically comes around September 16th, or one week ago. The bad news is that there is no front on Houston’s horizon for the next week or so, but the good news that I don’t think we’ll quite break 2005’s record, and have to wait all the way until October 7th. More below.
On Sunday, some nasty but very localized storms developed in northwest Houston along Cypress Creek near the Willowbrook area. We’re going to see the potential for similar storms today, although there should be a bit more south-to-north motion as moisture streams in from the Gulf of Mexico. Overall rain chances are about 50 percent, and while accumulations for most will be under one-half inch, we can’t rule out some isolated thunderstorms bringing a quick 1 to 2 inches of rain. High temperatures should be near 90 degrees.
Tuesday, Wednesday, and Thursday
As high pressure extends its reach over the Houston area, we should see rain chances drop back to around 10 to 20 percent for each of the mid-week days. Accordingly, we should see high temperatures around 90 degrees, with overnight lows in the low- to mid-70s. Mostly sunny skies should really help the area dry out after Tropical Storm Imelda’s nastiness.
Friday, Saturday, and Sunday
We don’t have much confidence in the forecast for next week, as high pressure backs off some, and moisture flowing in from the Gulf of Mexico could lead to some increased rain chances. Right now I’d peg daily rain chances in the 30 to 40 percent range with partly to mostly sunny skies. Highs likely will be near 90 degrees.
First cold front?
It’s not coming this week. However, there are indications in the global models of a pattern shift by around the weekend of October 5th that should usher in the region’s first front. Based upon the historical information in the chart above, that would be awfully late for Houston. But right now we don’t see much evidence for a front much before then—sorry.
We’ve had some questions about Tropical Storm Karen, which will approach Puerto Rico on Tuesday of this week. It will be moving due north at this time, but later this week there are some significant questions about what will happen to Karen, which should remain a relatively small storm.
High pressure developing to its north could block its movement and force it westward—or Karen could dissipate altogether. Readers of this site will probably be worried about Karen eventually moving westward, across the Florida Peninsula, and into the Gulf of Mexico toward Texas. However, there are way too many unknowns right about after about day five of this forecast to make any confident predictions.
Bottom line: Never say never, but any effects for Texas are low probability. We’re definitely not worried. You shouldn’t be worried. And if that changes we’ll certainly let you know as soon as possible.