if (sigmet.getForecastGeometries().get().get(forecastIndex.get()).getNoVaExpected().isPresent()&&
sigmet.getForecastGeometries().get().get(forecastIndex.get()).getNoVaExpected().get()) {
Can be replaced with:
if (sigmet.getForecastGeometries().get().get(forecastIndex.get()).getNoVaExpected().orElse(false)) {
Can be replaced with:
Note that the getter names have changed.