PHOENIX (AZFamily) — Big weather changes are on the horizon for Arizona as we head into the second half of the workweek and the weekend.

Look for a high of 103 degrees today in the Valley, which is just a few degrees above normal for this time of year. Skies will be mostly sunny, and winds should be fairly light.

A weak weather disturbance pushing through the region will bring a slight chance of showers and isolated thunderstorms today to far northern and far eastern Arizona. Dry and quiet conditions are expected Thursday through Saturday, with a slow warming trend.

Look for a high of 106 degrees by Friday in the Valley, with 104 expected on Saturday.

Two weather features bring big changes for the weekend ahead. An area of low pressure is expected to develop and linger off the coast of the Baja Peninsula to the southwest of Arizona. At the same time, a tropical system is developing further south off the southern coast of Mexico. It’s expected to become either a tropical depression or a tropical storm by later today.

By the weekend, the area of low pressure will move through our region, helping to pull in tropical moisture from the decaying tropical system into Arizona. This will increase rain chances mainly Sunday. Some weather models show rain chances as early as Saturday night, but the better chance is looking to be Sunday afternoon and evening, when isolated thunderstorms are also possible. Rain chances for the Valley on Sunday are currently near 50%.

Temperatures will warm to the upper 90s Sunday through next Tuesday. Dry weather returns by Monday.

See a spelling or grammatical error in our story? Please click here to report it .

Do you have a photo or video of a breaking news story? Send it to us here with a brief description.