well here's the deal with that...communication is a huge part of being a meteorologist...it's your job to use your knowledge and training to disseminate/communicate information to the general public or clients...
if communication is a weak area for you, then you need to work on it...you may never be the best public speaker or the most eloquent...but you can build adequate skills for what you need to do...in the field of meteorology, it is absolutely imperative you know how to communicate...
not trying to go all psychologist on you...but because you know you have a weakness in communication, it seems like you are hyper aware of your "deficiency" and this leads to a lack of confidence...and a lack of confidence will also hinder your ability to communicate effectively...
if you really truly want to improve, you start off with a basic public speaking class...or join something like Toastmasters...you'll be surprised at how much easier public speaking is once you boost your confidence...
also, it seems as if you need to work on your interviewing skills...this will also improve if you boost your confidence/comfortlevel with verbal communication...it could be that because you don't think you are a good communicator you worry too much while you are trying to communicate and that worry actually gets in the way of you being able to communicate effectively..
here's the deal...i don't usually share this information...but i stutter...and i am painfully aware of how that effects my ability to verbally communicate...in the beginning i passed up some job interviews because i didn't want the interviewer to hear me bumble around like an idiot...and i still remember this horrid interview i had with the USGS EROS Data Center...oh my, i crashed and burned, to the point where i only got through half the interview and they stopped it and said "Thanks but no thanks"
but, this is who i am...i can't make it go away, so i find away to work with it...it will always be a bit harder for me than the rest of the population to verbally communicate, but i can't hide from life...i just have more confidence now...and if i mess up, well, it happens...i just stop, take a breath and start over...