During the test period, rainfall was associated
with passage of cold fronts and SCAZ events over
Sa˜o Paulo State. Two rainy periods associated with
the SCAZ events (17–21 and 24–28, December,
2001) were observed; however, these events did not
affect all stations, since they reached only Minas
Gerais and Rio de Janeiro States (north of Sa˜o
Paulo) (Fig. 1). Thus, the continuous period of
rainfall recorded in the stations was only associated
with frontal systems. SCAZ was not present in
January, 2002 but cold front interactions with
ULCVs produced instability over the region, thus
contributing to a period of continuous rainfall and
rainfall peaks. Two SCAZ episodes were observed
in 4–7 and 16–24, February 2002, which affected
significantly the weather at the stations. The
occurrence of rain in the remaining period was
associated with new cold fronts.