Weather fronts - cold fronts, warm fronts and air masses
The uneven heating causes temperature differences, which in turn cause air High and low pressure areas, wind, clouds, and precipitation. When a cold front passes through, temperatures can drop more than 15 On a weather forecast map, a cold front is represented by a solid line with blue. Thermodynamics: In general, the relationships between heat and other properties (such as temperature, pressure, density, etc.) In forecast discussions.
The watch area may be upgraded to a warning or advisory - or canceled - based on updated information and analysis. Therefore, emergency management officials and the public should prepare to take action.
Watches are normally issued based on seismic information without confirmation that a destructive tsunami is underway. It forms during night and morning hours in late fall and winter months following the first significant rainfall.
A leading cause of weather related casualties in California. Turbidity The thickness or opaqueness of water caused by the suspension of matter. The turbidity of rivers and lakes increases after a rainfall. Turbulence Irregular motion of the atmosphere, as indicated by gusts and lulls in the wind. Turkey Tower Slang for a narrow, individual cloud tower that develops and falls apart rapidly.
Formulation of Weather Forecasts
The sudden development of turkey towers from small cumulus clouds may signify the breaking of a cap. Turning Point In hydrologic terms, a temporary point whose elevation is determined by additions and subtractions of backsights and foresights respectively. A similar structure exists over the Atlantic Ocean, where the mean trough typically extends from Cuba toward Spain.
Like the mesocyclone, specific criteria involving strength, vertical depth, and time continuity must be met in order for a signature to become a TVS. Existence of a TVS strongly increases the probability of tornado occurrence, but does not guarantee it.
A TVS is not a visually observable feature. Forecast sky cover height and amount of cloud basescloud tops, visibility including vertical visibilityweather, and obstructions to vision are described for a corridor 25 miles either side of the route.
Ceilings are always above ground level. Twilight The average time of civil twilight, which is the time between civil dawn and sunrise in the morning, and between sunset and civil dusk in the evening. Twister In the United States, a colloquial term for a tornado. Two-Ribbon Flare In solar-terrestrial terms, a flare that has developed as a pair of bright strands ribbons on both sides of the main inversion "neutral" line of the magnetic field of the active region.
A noise storm composed of many short, narrow-band bursts in the metric range - 50 MHz. Narrow-band emission that begins in the meter range MHz and sweeps slowly tens of minutes toward deka- meter wavelengths 10 MHz.
CLIMATE & WEATHER
Narrow-band bursts that sweep rapidly seconds from decimeter to dekameter wavelengths - 0. These include surface and upper air observation reports, readings from automatic weather stations such as air temperature, humidity, rainfall, etc from Hong Kong and other places in the world, as well as meteorological satellite and weather radar data. Forecasters need to analyze the latest weather data carefully and determine what weather systems and relevant mechanisms responsible for the current weather situation.
During the analysis, the spatial and temporal distribution of various observed weather elements will be compared with those of typical weather systems. The purpose is to sieve through huge amount of data to determine the most likely weather system, such as cold front, trough or tropical cyclone, will affect the local weather.
Forecast evolution of weather system Numerical weather prediction NWP products are widely used nowadays Figure 1 in forecasting the evolution of weather systems. NWP is performed by using a computer to simulate the motion of air in the atmosphere.
An NWP model is a suite of computer programs to simulate the atmospheric motions.
Glossary Terms | National Weather Service
Such a model incorporates different laws of Physics, including Newtons Laws, gas law, thermodynamics equations, fluid mechanics, etc. If atmospheric conditions are such that precipitation can occur and the temperature is above freezing, then rain may form.
If the temperature is below freezing, then snow may form. The type of precipitation is also affected by the temperature in the layers of atmosphere through which the precipitation falls. For example, if precipitation starts falling from clouds as snow and then passes through warmer layers of atmosphere, rains falls.
If the rain then passes through colder layers of air, hail may form. Sometimes, the precipitation will not fall to the ground at all.
Formulation of Weather Forecasts
If the air layers are dry enough, the moisture may evaporate before reaching the ground. Humidity Humidity is the amount of water vapor in the air.
Most atmospheric water vapor comes from evaporation of water from the ocean or other bodies of water.
Water vapor in the air greatly affects the type of weather we have. It is the source of all clouds, fog, and precipitation. Water vapor also helps warm the air when it absorbs energy from the sun.
Dew Point Dew point is the temperature that air would have to be cooled to in order for the air to be saturated with water vapor. In other words, it is the temperature at which an object, such as a blade of grass or a car windshield, will become wet with water from the air. Dew point affects how comfortable you feel.
By afternoon, it warmed up to 90 degrees, but the dew point stayed at You would definitely feel sticky and hot and you would think the humidity was very high! This would not be the case. Dew point and humidity are important because water in the air, in the form of water vapor, clouds, or liquid, greatly affects the weather.
How can dew points be used to predict the weather? In terms of weather, dew point is a good measure of the possibility of forming fog or having thunderstorms. It can also be a tool to predict low temperatures for the night.
Since dew point is the temperature the air would have to be for saturation to occur, if the difference between the air temperature and dew point is small, there is more moisture in the air and clouds and fog will likely form.