NOAA’s rain outlook suggests that a large part of Texas, including Houston, will see between one and three inches of rain. Isolated locations could potentially get more than that if persistent heavy rain sets up over the same area.
The rain may be heavy enough to cause street flooding. NOAA’s Weather Prediction Center recently upgraded the flood risk for Houston from “marginal” to “slight”, which is a level two out of four risk (yellow on the image below). Specifically, level two means there is at least a 15% chance of flash flooding within 25 miles of any point.
Timing of the rain:
Showers and thunderstorms will gradually increase in coverage during the first half of Thanksgiving, becoming most widespread by the afternoon and evening. There will be a break late Thursday night before more widespread showers (with very few thunderstorms) arrive on Friday, especially Friday afternoon and Friday evening. A few showers could linger into early Saturday morning, then it’ll be dry for the rest of the weekend.
In addition to heavy rain, there is a relatively low risk of severe thunderstorms on Thanksgiving. Houston and surrounding areas are in a level one out of five risk for severe storms. Specifically, the Storm Prediction Center says there is a 5% chance of severe winds and a 2% chance of a tornado within 25 miles of any point.
As for temperatures, we’re warming through Thanksgiving, then cooling Friday and Saturday, then warming again Sunday and beyond.