Kitty cannot cross 5 yards in the space it would take Storm to simply create a thunderflash to blind Kitty or create a monsoon to dizzy Kitty.
We're assuming Kitty can phase through Storm's initial attacks, and somehow cross 5 yards in time to kill Storm.
Which isn't happening. A far more likely scenario is Storm flying straight into the air.
If Storm doesn't think she can fly up high enough in time, then she can use lightening to blind Kitty or a sudden fog to hide her from Kitty.
Once Storm's in the air, Kitty can't do sh**. Sure she can "elevator" around the air but Storm can simply evade and fly faster. And she can cloak herself with a variety of precipitation effects thus hiding her from Kitty.
Until then, Storm can focus on creating an electrical impulse that's capable of harming Kitty's phased form. Which may take awhile but with her energy perception abilities and her sudden increase in capabilities to control a portion of the electromagnetic spectrum. It's not that far off...