With an occluded front,

grab a sweater because it's going to be cool
put on a tank top because it's warming up
get out of the area because a tornado is coming

grab a sweater because it's going to be cool

A front is a zone of transition between two air masses. It is mainly responsible for the type of weather condition exhibiting in an area.  An occluded front forms when a cold air mass moves over a warm air mass. It is evident that cold air masses are faster than the warm air masses because of low density of air. The cold air masses are prominent over the hot air masses, hence this results in the winter conditions.

Therefore, grab a sweater because it's going to be cool is the correct option with the occluded front. As, the occluded front likely to bring winter conditions.    

your body is trying to warm itself up. or more precisely, sensors in your skin send messages to your brain to generate heat to your body.