Why does it get colder when the sun rises?

Question

Location: Las Vegas
Time of year I've noticed this: February
What happens: sudden 5 to maybe even 7 degree temperature drop everyday a couple of minutes right after morning light appears.

I've heard hikers call this "Sun Suck".
But what causes it?!!!?

Answer 1

I use to work as an airport weather observer and had noticed that this occurs often. Based on my observations, this occurs most often when the environment is stable and/or the temperature drops down to near the dew point. In other words, relative humidity is near 100 percent. In both cases, it is best that the surface winds are near calm at sunrise.

When the environment is stable at night, the coldest air sinks to the ground surface. An official temperature measuring device by international standard is about 4 to 6 feet above ground. (Some are even higher, like RAWS weather stations, are even much higher above the ground.)

With the cooling temperatures at night, the relative humidity (RH) will go up. If the RH is high and near 100 percent right before sunrise, condensation may occur on or around the sensor area. This condensation would evaporate with the heating of the morning sun. This evaporation process will briefly cool the air near the location of the sensor. As a result, the temperature will drop suddenly after sunrise.

Here is the other possible reason. With a stable environment and calm wind, the coldest layer of air usually settles below the temperature sensor. When the sun comes up and starts warming the surface, the colder air below the sensor will start to mix upward. When this layer of air reaches the sensor height, the temperature will briefly fall. Then it will start to rise when this colder layer mixes out.

So in either case, it will likely result in a brief drop in temperature after sunrise.

Answer 2

lots of the individuals who spoke back touched on the proper answer maximum did not. floor temperature is a stability between the incoming skill (almost all of that's from the daylight in the type of seen gentle or short wave radiation) and outgoing skill somewhat in the type of infrared or lengthy wave radiation. The temperature will proceed to chop back so long because the earth floor receives a lot less skill than it radiates into area. This crossover takes position no longer in the previous sunlight upward push yet a touch after damage of day. With all different climate parameters being equivalent, floor temperatures received't commence to extend till about 30 to 40 5 minutes after damage of day even as the perspective of the daylight will enhance to the point that that's radiant skill exceeds the quantity of outgoing infrared radiation. many times there are winds or terrain consequences that cancel this out. it really is maximum probably talked about in flat desert aspects on sparkling nights without wind. also, this solutions the question why is the most constructive temperature of the day in overdue afternoon. The temperature maintains to upward push with the help of the day till the daylight is low adequate that the infrared radiation of the earth exceeds the incoming short wave radiation of the daylight. This extremely many times takes position very overdue in the afternoon, an hour or 2 in the previous sundown. for sure this can get replaced with the aid of different impacts which includes clouds, rain or chilly fronts.

Answer 3

Good question. This occurs for the same reason that maximum temperatures for the day due not occur when we have maximum solar insolation around noon but rather later in the afternoon around 3 - 4 p.m. When the sun comes up it must be absorbed by the earth, the earth must begin to warm and re-radiate longwave infrared radiation which then heats the atmosphere. So there is this lag between solar insolation and heating. Hope this helps a little.

Answer 4

Because as the sun comes up it heats the mountain tops causing some of the snow to melt. This sends cold are into the valleys.

Answer 5

as the sun heats up the air it rises pulling the cooler air over you
probably not really getting colder just feels that way