Is there a callback or promise for Aurelia show.bind?

In my template, I have a div I want to use as a tooltip of sorts. When I have a model selected, the tooltip shows, and then I use tether to put it in the correct spot. If I set tether immediately after setting the model that makes the element show, it's size isn't computed properly and Tether doesn't properly limit constraints. If I debounce it with a setTimeout, I can get it in the right place, but that feels hokey. My question:

Is there some sort of callback mechanism I can attach to that is called after show.bind has made the element visible?

My template:

<div ref="tooltip" show.bind="selectedAlert" class="homepage-stats-tooltip panel panel-default">
    <div class="panel-body">
        <h1>${selectedAlert.Name}</h1>
        <dl>
            <dt>Normal</dt>
            <dd>${selectedAlert.NormalVolume}</dd>
            <dt>Current</dt>
            <dd>${selectedAlert.CurrentVolume}</dd>
        </dl>
    </div>
</div>

The function that sets the model and calls Tether:

showTip(event, state) {
    if (!state) {
        return;
    }

    console.log(`Show tip for ${state.Name}.`);
    this.selectedAlert = state;

    setTimeout(() => {
        new Tether({
            element: this.tooltip,
            target: event.target,
            attachment: "top left",
            targetAttachment: "top right",
            constraints: [
                {
                    to: this.usMap,
                    pin: true,
                    attachment: 'together'
                }
            ]
        });
    }, 10);
}

Thanks!