Archives
Categories
WeatherGuys Links
Category Archives: Seasons
Why don’t trees freeze and burst in the winter like cold pipes?
When liquid water freezes, it expands as the water molecules spread out to form a solid crystalline lattice. If the freezing water is contained in a closed vessel, such as a metal pipe, it can press hard on the sides as it expands, causing the container to burst.
Trees contain water that is transported throughout the tree by the phloem and xylem, which we can think of as pipes.
Continue reading
Will the recent the groundhog predictions come true?
Punxsutawney Phil saw his shadow, which means there will be six more weeks of winter. On the other hand, Jimmy the Groundhog in downtown Sun Prairie did not see his shadow at sunrise during the 78th annual Groundhog Day Prognostication, which per tradition means we are due for an early spring. Which to believe?
We don’t put stock in either. Continue reading
Why are viruses more common in Winter?
Colds and the flu are caused by viruses, not by cold wintery conditions. Viruses such as rhinoviruses, which cause the common cold, and influenza viruses spread from person to person through respiratory droplets or physical contact, regardless of the temperature outside.
However, weather and climate do play a role in why colds and the flu are more common in winter though. The colder temperatures associated with winter affect how viruses behave in the environment. Winter’s colder temperatures and lower humidity help viruses survive longer and spread more easily. Research studies show that many respiratory viruses survive longer and remain infectious for extended periods of time in cold, dry environmental conditions.
Dry air also causes tiny droplets released when people breathe, talk, cough, or sneeze to evaporate quickly. These droplets evaporate quickly, creating smaller particles that stay suspended in the air longer and travel farther, increasing the chance that others will inhale them.
Winter’s low humidity can dry the lining of one’s nose and throat. This reduces the effectiveness of mucus, which normally traps viruses and helps move them out of the airways.
In cold weather, social events tend to be indoors, bringing us in close contact with others. This increases the chance of the spread of a virus.
Preventive measures such as vaccinations, good hygiene practices, and wearing masks in crowds help to reduce the risk of viral infections. Improving indoor ventilation and maintaining adequate humidity during winter can also reduce transmission risk. Cold weather can be challenging for people with existing respiratory conditions such as asthma. Continue reading
Why is Wisconsin winter weather so cloudy and grey?
Climatologically, the winter months are the cloudiest time of the year in Wisconsin. Wisconsin’s average monthly cloud cover for December, January, and February for the years 2006 to 2024 was 65.3%, 61.1% and 50.5% respectively. There are a few factors that contribute to this climate observation.
Wisconsin sits in a latitude band where synoptic scale storm systems often pass nearby. This scale is associated with large weather patterns like mid-latitude cyclones and anticyclones. During the winter, the mid-latitude storm tracks tend to be along the polar front and the upper tropospheric jet stream. These winter storms have large stratiform cloud shields that move across the Midwest, producing more persistent cloudy conditions. Even when storm centers miss the state, these cloud shields can linger for days afterward. Continue reading
Category: Climate, Meteorology, Seasons
Comments Off on Why is Wisconsin winter weather so cloudy and grey?
Comments Off on Why is Wisconsin winter weather so cloudy and grey?
Will shifts in the polar vortex cause extreme day-to-day temperature fluctuations to become more common?
The polar vortex is a large area of low pressure in the lower stratosphere that is bordered on its southern edge by the polar night jet — so-called because it develops as the sun sets at high latitudes after the autumnal equinox, creating large and deep pools of cold air. The characteristics of this stratospheric polar vortex have a substantial influence on wintertime temperatures in the lowest part of the underlying troposphere, which is where we all live.
The nature of the polar vortex changes throughout the winter. When the vortex circulation is largely west-to-east around the pole, it tends to contain the most extreme cold air masses at high latitudes. When it is characterized by high amplitude waves, often associated with a weaker vortex, it can initiate rapid transport of warm air poleward in some locations and frigid air equatorward in others. Such waves, or lobes, of the polar vortex can pinwheel over the Northern Hemisphere, sending cold air southward in association with weather systems tied to the underlying tropospheric jet stream. Continue reading
Category: Meteorology, Phenomena, Seasons
Comments Off on Will shifts in the polar vortex cause extreme day-to-day temperature fluctuations to become more common?
Comments Off on Will shifts in the polar vortex cause extreme day-to-day temperature fluctuations to become more common?
