$(window).on('resize.ui.modal', function(){
    $modal.position({
        my : "center",
        at : "center",
        of : window,
        using: function(pos) {
            var topOffset = $(this).css(pos).position();
            if(topOffset.top < 30){ $(this).css("top", 30) }
            if(topOffset.left < 0){ $(this).css("left", 0) }
        }
    });
})