Last night Matt provided a solid overview of the reasoning behind Houston’s flash flood watch for Wednesday, and truthfully not much has changed. Wednesday and (especially, we think) Wednesday night have the potential for widespread, heavy rainfall with possibly some severe thunderstorms. We’re not expecting anything too extreme, rain-wise, but some street flooding is possible later tonight.
The big question for today is timing. As of about 7am, a fairly robust line of strong rain showers extends along a line almost half way between San Antonio at Houston. It’s not clear when the bulk of the rainfall will arrive. It could be as early as just before noon for western parts of the city, but not until afternoon, or even evening for most of the city. (Note: If you haven’t seen much or any rain by sunset, it doesn’t mean that the forecast is a bust, or the rain “missed” us. Hold on.) We’ll be watching closely, and update this site as necessary. Highs today should reach about 80 degrees under mostly cloudy skies.
Sometime later tonight, probably about 9 to 11 pm, the forecast models move a boundary into the Houston region, and this should serve as a focusing point for heavy rainfall between that point and perhaps 2 to 4am on Thursday morning. This is the period during which we think the heaviest rain showers will move into Houston, along with the potential for some inclement weather like hail. Most of the area will probably see 1 to 3 inches of rain, but depending on where this boundary sets up—perhaps along the US-59 corridor, perhaps closer to the coast—we could see higher amounts than this. Either way, if you’re a light sleeper, thunder and lightning will probably wake you at some point tonight.
This boundary should move offshore sometime on Thursday morning, bringing an end to the rainfall, hopefully before the morning commute really gets going. Skies should clear up on Thursday afternoon, with highs rising to around 80 degrees.
Friday and Saturday
As advertised, the outlook for Friday and Saturday remains exceptional, with highs near or at 80 degrees, sunny skies, drier air, and cool nights with lows around 60 in Houston, and cooler to the north while a bit warmer right on the coast.
Easter looks nice, too, with highs around 80 degrees, partly to mostly sunny skies, and a touch more humidity as the onshore flow resumes. Rain chances are essentially zero.
The forecast for next week isn’t entirely clear, but at this time, I think we’ll see a bit warmer weather, with highs in the low 80s, for the most part, and lows in the 60s and 70s. Rain shouldn’t be much of an issue before Wednesday, and perhaps not even by then.