If you plan on visiting the lounge, you can get ice there and bring it along on your trip. Maybe pack a small softside cooler and ziplocs to keep things cold?

You're also allowed to carry ice packs on, but its best if you can get them to the airport totally frozen -

Frozen liquid items are allowed through the checkpoint as long as they are frozen solid when presented for screening. If frozen liquid items are partially melted, slushy, or have any liquid at the bottom of the container, they must meet 3-1-1 liquids requirements.