Welcome to the forum.
You could get an Enertia now, ride it for a year (especially in your climate), then sell it to get the Empulse.
I would expect that used Enertias will be similar to used 250cc bikes that are good for someone new to EV motorcycling. The demand is strong in my area of the country for used entry level bikes.
I am planning to keep my Enertia for a few years before I move on to an Empulse. I am financing it with a zero interest, two year deal with Best Buy. I would bet that there will be future upgrades available to the Enertia. Brammo is intending to keep the Enertia model along side the Empulse model for customers to buy.
If the Enertia meets your needs now, I say go for it and have a blast.