few showers(=isolated; в сводке погоды; few is used interchangeably with isolated (NOAA); not many, amounting to a small number: used to describe a small number of showers over a time period or an area (bom.gov.au) Lavrin)
widely scattered showers(roughly speaking widely scattered (20 % affected area) stands for isolated (about 10 % affected area); в сводке погоды; E.g.: Partly sunny in general with a few isolated to widely scattered showers possible. Lavrin)
isolated showers(roughly speaking isolated (about 10 % affected area) stands for widely scattered (20 % affected area) в сводке погоды; E.g.: Isolated showers are moving across East Tennessee this Memorial Day and will be followed this afternoon by showers and thunderstorms. Lavrin)