Better than science, I have pictures. As you can see in two of the pictures, in October the leaves have color but not in the warmer sun tanning months.
FWIW (SREF grain of salt warning) the last SREF run brought .6 to IV4 and has been fairly consistent with a mean of 10 inches or so here.
http://www.spc.noaa.gov/exper/sref/fplumes/index.php?YMD=20150126&RT=09&PRM=Total-QPF&SID=1V4&INC=ALL&NNC=&max=&min=&mZOOM=8&mLAT=44.49234506559211&mLON=-72.82372153625488&mTYP=roadmap
Plus the SREF do bring some nice dendrite growth up this way. I don't look at the SREF for much but I do like the dendrite growth loops.
http://www.spc.noaa.gov/exper/sref/sref.php?run=2015012603&id=SREF_prob_dend_50__