preload fpc cache

hi , i’m a beginner in magento. i use built in cache and category pages load relatively fast. the problem i have when the cache is emptied the first user takes 20 seconds to load(300 products). after that i assume the page is fetched into cach. is there any way to preload a few category pages , just aftet the cache is cleaned? im talking about 20 to 30 pages. in other words to simulate a user going into the page and “waiting” until it cached. thanks in advance