[--MAIN HOME--] [--ALL HABYHINTS--] [--FACEBOOK PAGE--] HOW DOES A NIGHTTIME RAIN IMPACT WEATHER THE NEXT DAY? METEOROLOGIST JEFF HABY Some rain events occur at night. This is especially true for rain that occurs from dynamic lifting mechanisms such as from fronts and positive vorticity advection. Overnight rains can significantly influence the weather the next day. It can help create an increase of early morning cloud cover. This can keep the temperature cooler than it otherwise would have been due to the clouds blocking out the morning sun. Ironically, it could also make it warmer than it otherwise would have been since significant cooling can occur on clear nights. Thus, forecasters can have a challenging temperature forecast when it rains overnight. The added moisture changes the weather also. Evaporation of moisture into the air can help cool the air. The increase of moisture though can also trap more longwave radiation which can lead to warmer conditions. This is another ironic situation forecasters have to deal with. The added humidity when combined with warm temperatures can make it feel warmer (heat index). Each situation is unique. The added moisture to the air in some cases can increase the chance for rain during the day since a greater amount of moisture can help it more easily rain during the day. Much depends on the stability profile of the atmosphere. For example, a strong cold front can bring rain overnight but can also bring in very stable air the next day and thus no rain.