No, tornadoes are accompanied by low pressure.
Not necessarily. The intensity and size of a tornado are more closely related to the atmospheric conditions that create the storm, rather than the specific air pressure. Factors such as wind shear, temperature, and humidity play a more significant role in determining the size and strength of a tornado.
a high pressure system is moving into an area
The same as the atmospheric pressure on anything else on the surface of the earth.
Rain typically occurs in low atmospheric pressure systems where air rises, cools, and condenses to form clouds and precipitation. High atmospheric pressure systems typically bring stable and clear weather conditions with less likelihood of rain.
pressure is usually measured relative to atmospheric this is called gauge pressure. if you compare against absolute zero pressure (vacuum) this is called absolute pressure.
A drop in pressure usually indicates bad weather.
There is a negative correlation between precipitation rate and atmospheric pressure. As atmospheric pressure decreases, it usually indicates a low-pressure system approaching, which can lead to rising air and ultimately increased chances of precipitation. Conversely, higher atmospheric pressure tends to be associated with clearer skies and lower chances of precipitation.
Rising atmospheric pressure typically indicates that a high-pressure system is moving into an area, which often leads to clearer skies and more stable weather conditions. This increase in pressure is associated with descending air, which inhibits cloud formation and precipitation. As a result, rising atmospheric pressure usually signals fair weather and can suggest that a change in weather is on the way.
Temperature: usually room temperature (25 degrees Celsius) Atmospheric pressure: usually 1atm
A barometer.Barometric pressure is usually read and rated in millibars of atmospheric pressure. A standard day at sea level, would be 29.9 on the barometric scale. That is, neither a high or low pressure in the area and generally sunny.
Gauge pressure usually refers to the pressure difference between ambient, atmospheric pressure and the pressure in a vessel or line. A gauge pressure of zero would mean that the vessel or line was at atmospheric pressure. Normally the pressures of interest are ABOVE atmospheric so the gauge pressure is positive. Vacuum gauge pressure measures how far BELOW atmospheric pressure a vessel or line is. As such vacuum gauge pressure may be measured as a negative number - or for convenience it may be reported as a positive number with the caveat that it is "vacuum gauge pressure", meaning that the reported pressure is how far atmospheric pressure is above the pressure in the vessel or line.
Barometers, such as mercury and aneroid barometers, are commonly used to measure atmospheric pressure. Other instruments like electronic pressure sensors and weather balloons equipped with instruments can also measure atmospheric pressure.