There is a text box in the top left which says "Local forecast by "City, St" or Zip Code". Enter your city, state, or zip code in that box and select the location. Then it opens the forecast page. I have included a link to San Francisco below. You get a full 10 day forecast. I'm not sure what else you want.
You must be counting the day and night forecasts as separate days. There are no 10-day forecasts on the linked page. The furthest-out forecasts are 7 days into the future.
https://forecast.weather.gov/MapClick.php?lat=37.7771&lon=-1...