#1
So the action at the lower frets for me is fine, but at the higher frets (7th and on), it is very high. Any ideas why this would be?
#2
probably your neck isnt straight and you need to straighten it becasue there's too much relief
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Jackson SL-3 Soloist w/ licensed Floyd Rose
Peavey VK 100 Head
Earcandy Boa 2X12 Cab w/ 70 watt Speakers
Fender Frontman 15 Watt Practice Amp

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#4
the one major thing that I noticed is that I dont' recall the higher frets having such a high action; it happened within the last month or two...hmm, maybe I need to adjust the truss rod? Before I go cranking on the thing, I would like clarification from more experienced guitarists here..
#5
chances are that the changes you are describing are the effects of humidity. it looks like you live in Iraq so this isn't uncommon at all.

without seeing the guitar it is hard for me to tell you whether or not you need to adjust your action or your neck relief. the first thing you want to do is check your neck relief and then your neck angle. here are some articles concerning these two things:

http://www.frets.com/FRETSPages/Musician/GenSetup/TrussRods/TrussRodAdj/tradj.html
http://www.frets.com/FRETSPages/Musician/Guitar/Setup/NeckAngle/neckangle.html

if you check these and everything is good to go, you can safely proceed on with lowering the action to fix your problem. action is adjusted at the nut and at the saddle. adjusting the action at the nut is a bit more of a bother and has a lesser effect on the condition you are describing so i wouldn't even bother with it. i'd immediately go to the saddle for adjusting the action. here is an article concerning that:

http://www.frets.com/FRETSPages/Musician/Guitar/Setup/LowerAction/loweraction01.html
#6
if I sand the bridge down, won't the lower frets create fret buzz? It's only past the 5th or 6th that has a high action.
#7
^--You dont sand the bridge down, you sand the saddle down. And it will only create buzz if you sand too far.
It sounds to me like your neck may have too much relief, but as Jimataka said, its difficult to diagnose without being able to see the guitar.