|WX AND TIME OF DAY: EVENING
METEOROLOGIST JEFF HABY
Evening has a time frame from sunset to bedtime. Since bedtime is highly variable, a general time frame for the end of evening is sometime
between 9 and Midnight. Sunset is highly variable also since it depends on the time of year and latitude. What is considered evening will
vary greatly from one person to the next as far as when it begins and when it ends. For this writing, evening will be taken to be from 6 pm
to 10 pm. When it comes to weather, this time of day is typically when the temperature cools off, the troposphere starts to stabilize and
the character of storms changes.
One generality is that temperature gradually cools. Once the sun sets, the ability to warm temperature through solar radiation ends. On a typical
day this means the temperature will cool off since the ground cools by emitting longwave radiation. The cooling off tends to not be as abrupt
as the warming in the morning hours. Typically the temperature will gradually cool off hour by hour from sunset to sunrise. The low temperature
for the day typically does not occur in the evening but occurs around sunrise.
Since the temperature cools off, this begins the process of the atmosphere stabilizing. The threat from severe weather tends to be less in the
evening as compared to the afternoon. This is a generalization though since strong storms and convective systems do often continue into the
evening hours. The cooling of the ground though reduces instability and this contributes to severe storms being less common in the evening
as compared to the afternoon.
While severe storms are less common in the evening as compared to the afternoon, significant storm events still occur. Storms with heavy rain
and lightning can occur from convective systems, lifting mechanisms that move through in the evening and from storms that have held together
from the afternoon and into the evening.