In a warm occlusion, relatively cooler air rides up over cold air. This results in a cold front aloft. If the air ahead of the warm front is colder than the air behind the occlusion, then it is a warm occlusion. 

Surface temperatures are cold ahead of the front and warm after passage of the front. Surface dew points rise after passage.  Visibility and weather are usually poor before and during passage, and improve after passage. Pressures will fall ahead of the front. The lowest pressure occurs during passage of the front. After the front passes, pressures rise.  Surface winds can be gusty. They are usually from the south to southeast before passage, and rotate clockwise to the west - northwest after passage (veering winds).