Premise: Global warming is affecting snowfall throughout the state. In 2004, nearly 60% of all precipitation in our state was in the form of snow, whereas by 2009, that percentage had dropped to just 42%.

Conclusion: In 20-30 years, the state may have no snow at all.
Now, let's analyze each option to know which aligns with the climatologist's argument.

Option A - Incorrect:
According to the passage, we only know about the decrement that happened between 2004 and 2009. And from the passage conclusion, we can be totally expressive that the percentage will continue to decrease because of the usage of "may" which implies possibility (i.e can either increase or decrease).

Option B - Incorrect:
The climatologist argument wasn't specific about this claim on if global warming will cease in the state in 20-30 years. We can only decode an expression of possibility "may have no show" which implies that there can either be an increase or decrease. So, therefore, this option is wrong.

Option C - Incorrect:
This argument is concerned about global warming as a factor affecting snowfall in the state. No other factors were stated in the passage and as such, this option's claim is invalid.

Option D - Correct:
The statement, "in 2004, nearly 60% of all precipitation in the state was in the form of snow but in 2009, the percentage dropped to 42%", is a validation of this option. As a result, the amount of precipitation in 2009 was not significantly greater than it had been in 2004. Therefore, this option is the correct answer.

Option E - Incorrect:
This option doesn't correlate with the climatologist's argument because the argument is concerned about snowfall. Hence, the volume of rainfall is contrary to the argument.