A/C blows cold and strong for 15 minutes and then blows cold and very weak until I turn off the car?

When I start up my car, the A/C is blowing cold air very strongly and has no issues with air flow. After about 5-15 minutes of driving the air flow will nosedive to almost no air flow even at the highest fan setting. I will feel just a tiny bit of cold air flowing out at the highest fan setting and it will remain like this until I shut the car off for twenty or so minutes and then it will repeat the same cycle. The cabin air filter is clean, air line PSI is optimal. I don't know the next step to check after this.