OK so I just got done flying and it was somewhat windy. The P4 was holding position perfect , not budging until a fairly strong gust hit and the P4 started ascending up. The gust lasted about a good 10 seconds but before the gust stopped I brought the p4 down and hand caught it. I uploaded my flight data to healthy drones and it says average wind was 12mph and gust was 19.7mph. Since I've never really flown in gusts this high is it common for the P4 to ascend while getting hit with a 20mph gust? I should also mention where I was flying is a parking lot surrounded by all desert which the parking lot is lower than the desert so the wind was coming over a hill sort of. I did walk up the hill and the wind was stronger than down on the parking lot. Now could the way the wind was blowing over and down into the parking lot caused the p4 to raise? The p4 was about 2 or 3 feet above the desert so about 20 feet above the parking lot. Any thoughts? Thanks and if this is a dumb question I'm sorry I'm still learning the ropes and how the p4 behaves.

Also It has never done this before

The P4 in my short experience doesn't like wind and i imagine no drone does.

I have seen my own P4 act very erratic in windy conditions with altitude and position, so i don't risk it anymore (I gave up when the drone wouldn't return to home the head wind was so strong it simply didn't have enough power to fly against the head wind)

The battery doesn't last long either in windy conditions because the drone is working hard to keep position (not good for motors i imagine)
I noticed the picture on the tablet i use as well goes to $hit with pixelation and lock ups when flying in wind.

I just wait for nice calm days now

Desert wind?!!

You're lucky it didn't get blown away with no hope of flying it back to you.  I shoot commercially in the desert (Stills) and have had tripods blow over, lights go airborne, and stuff just blows away never to be recovered.  Some people get blown off balance, e.g. women in high heels, as well by some odd gust.

The Autologic's Autopilot makers recommend not to fly over 10 and 15 is the limit they've seen with their app.  I have an old Dwyer wind gauge with the little pith ball that rises in winds between 2-10 MPH.  If it hits the top of the tube which is 10 MPH, I don't fly as it will likely get worse at some point, especially afternoons out there.  Put the drone in atti and watch it fly away.

Every environment is different as gmccurdy has mentioned. I live in ohio and it is pretty flat but there are trees to help break up the wind. I have flown the P4 in winds gusting to 16 mph and it handles pretty good. What I am wondering is if you were flying just under a thermal cause being in the desert and on a parking lot is a good setup. Thermals are what gliders use to ascend. But I wouldn't  fly if winds are higher then 16 mph.

so no flying in hurricane matthew... check
I'm in Florida

I live in South Florida.  I have never had any problems flying in 15mph winds.  You get that all the time at the beaches.

I live in southern California mountains and the wind here is often 25 to 30 mph.  It does not prevent me from flying and my Advanced handles it just fine.

Check out this video a about 1.2:  WIND

Thanks MD_Icarus for a video. How strong was the wind? What model Phantom are you flying? I can tell that the P4 drone is not just steadier in the air than the P3 but the gimbal is better. I noticed when flying both drones in 16 mph wind.

One thing to keep in mind in gusty wind conditions.
The Phantom, or most drones for that matter, use a barometer as the primary altimeter. This is a air pressure sensitive instrument, and it tells the drone to stay at a set air pressure level. When you let go of the left stick, it memorises that particular air pressure, and tries to keep the drone at that level.
When a gust of wind hits the drone, there is normally a rise, or drop in the relative air pressure, and the drone tries to compensate for it by either rising or lowering.
At lower altitudes, the ultrasound sensors as well as the vps sensors ( those little cameras at the bottom of the drone) help to keep the dron at a stable height.
I am not sure at what height the P4 prioritise which sensor, but the higher you fly, the more it will rely on the barometers, as the ultrasound and vps will not be that effective.
This would explain the rise and fall of your drone in gusty conditions.
By compensating with the left stick, you will have to help the drone if you want it to stay at a certain height, but it is not a problem. There are to this date no magic sensor that will keep your drone at a rock steady height in gusty conditions. There are simply too many variables.