Toril’s polar auroras. How far south can they be seen?

Well again, Master Ed! I was wondering about Toril’s polar auroras. How far south can they be seen? Do you get glimpses as far south as Silverymoon or are they mostly limited to above the Spine of the World? They are most brilliant and prevalent north of the Spine of the World, but the aurorae can be seen (on infrequent occasions) as far south as Triboar (so, south of Silverymoon and Everlund).@Realmslore

— Ed Greenwood (@TheEdVerse) March 25, 2020