If you want utmost stability in the wood you are using, you really need to know what the equilibrium moisture content (EMC) is for your given area. 14% in one area may be fine but not good in another area. A 14% moisture content is fine if your average humidity is 75%. Here is a calculator for determining the EMC for a given humidity and temp.
http://www.woodworkerssource.com/moisture.php
And here is a good article on EMC and wood movement:
http://www.thisiscarpentry.com/2010/09/03/moisture-content-wood-movement/
Now granted, you are just making a bowl so a little movement will not hurt you, like Victor says above.
Also, depending on the moisture meter you are using, be sure to correct the reading based on species. You should have a chart in your manual that shows the correction procedures. This is because most moisture meters are calibrated for Doug Fir and different species of wood have different specific gravities, affecting the moisture meter's readings.
Again, this is all if you want utmost precision. I am a little bit into technical accuracy so these types of things are important to me! Then again, I have a $400 moisture meter that i can input the specific gravity of the wood I am measuring and it will automatically correct for that species.