( ( Weather conditions ) ( ( ( are often ) ( described ( in ( terms ( of precipitation ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Weather) (NNS conditions)) (VP (VBP are) (ADVP (RB often)) (VP (VBN described) (PP (IN in) (NP (NP (NNS terms)) (PP (IN of) (NP (NN precipitation))))))) (. .)))
Weather conditions are often described in terms of precipitation .
(ROOT (NP (NP (NP (NNP Precipitation)) (ADJP (RB commonly) (JJ occur))) (PRN (-LRB- -LRB-) (PRP s) (-RRB- -RRB-)) (PP (IN along) (NP (DT a) (JJ cold) (NN front))) (. .)))
Precipitation commonly occur(s) along a cold front.