When you say weather magic , i would assume that you like to do spells in relations to to controlling the weather patterns i assume?
Do you have a specific purpose for doing that ? Weather is not chaotic and is balanced . You doing such spells only serves to affect the balance of nature . Unless you are doing it for a higher purpose than simply having the pleasure seeing the weather bent to your whim , I don't recommend doing so.
As to you wanting a better meditation technique , i would also need more information . What do you seek from your meditation?Self empowerment?Absorbing of cosmic energy?Relaxtion and atmosphere setting? There are many powerful meditation techniques catered to different purposes.Tell me so i can dispense the appopriate information.
Also , which diety or being do you work with to cast your weather spells? After all , i don't believe the power of one person is enough to influnece the weather to such extent you described.
As to how to word the incantation to a spell , you should try to make it rhyme . This is not simply to make your spell more beautiful and artistic but to make it easiear to remember. You would want to be able to say it all without thinking and go with the flow. You would want your words to spill out naturally . The incantation serves as a tool for you to express and send out your energy , nothing more . If you find that you are capable of doing that , an incantation is usually not needed.
As to what items to use , you can get some offerings to whichever diety or being you are working with to bring about change in the weather . But it is really up to you actually . If you decide to use any particular pre ritual before your casting , use their materials needed then. They are usually not needed and you should just simply use offerings at the very most to thank the beings that you are working with for their cooperation.
I hoped this helped .