What Mark Twain actually said about the weather in New England.

From http://www.twainquotes.com/18761223.html:

Old Probabilities has a mighty reputation for accurate prophecy, and thoroughly well deserves it. You take up the papers and observe how crisply and confidently he checks off what today's weather is going to be on the Pacific, down South, in the Middle States, in the Wisconsin region; see him sail along in the joy and pride of his power till he gets to New England, and then - see his tail drop. He doesn't know what the weather is going to be like in New England. He can't any more tell than he can tell how many Presidents of the United States there's going to be next year. [Applause.]

Well, he mulls over it, and by and by he gets out something about like this: Probable nor'-east to sou'-west winds, varying to the southard and westard and eastard and points between; high and low barometer, swapping around from place to place; probable areas of rain, snow, hail, and drought, succeeded or preceded by earthquakes, with thunder and lightning. [Loud laughter and applause.]

Then he jots down this postscript from his wandering mind, to cover accidents: "But it is possible that the program may be wholly changed in the meantime." [Loud laughter.]

(reported in The New York Times, December 23, 1876.)

http://www.islandnet.com/~see/weather/arts/twain1.htm says: "Old Probabilities" refers to Prof. Cleveland Abbe, who was a highly respected civilian meteorologist who worked for the U.S. Army Signal Service and later the Weather Bureau as a forecaster.