Understanding Weather Forecasting

• Weather forecasting uses tools, data, science, and technology to predict weather conditions in advance.
• Early weather forecasting relied on observation before the advent of computer models.
• The first computer-generated weather forecast was created in 1955.
• Weather forecasts inform daily life and long-term planning.
• Forecasting involves measuring temperature, pressure, precipitation, wind speed, and cloud cover, and sharing these readings.
• Weather forecasts help understand and prepare for the impact of weather on daily life.
• Severe weather forecasts are crucial for saving lives, property, and crops.
• Weather reports provide information on current atmospheric conditions, including temperature, pressure, wind speed, and precipitation.
• Weather forecasting aims to predict atmospheric conditions for the near future.

Weather Forecasting Tools

• Meteorologists use tools to measure and gather weather data.
• Tools for measuring current weather conditions include:
• Outdoor thermometers: air temperature
• Barometers: air pressure
• Anemometers: wind speed and direction
• Hygrometers: humidity
• Radar detects objects in the air, primarily precipitation.
• Radiosondes are balloon-borne instruments that gather precise atmospheric data during severe weather.
• Radiosondes measure and transmit pressure, temperature, and humidity to a ground station.
• Data from various instruments are fed into computer models to generate forecasts.

Barometers

• Barometers measure atmospheric pressure, which is the weight of air above a given level.
• Air pressure and temperature are related; warm air correlates with higher pressure, and cold air with lower pressure.
• Temperature differences create pressure differences, causing air to move from high to low-pressure areas.
• Air movement seeking balance creates weather.

Radar

• Radar (Radio Detection and Ranging) is a critical tool that emits microwave pulses.
• When the wave hits a target (rain, cloud, insect), part of it bounces back.
• The return is amplified and displayed, with brightness indicating rain intensity.
• Radar detects the location and intensity of precipitation and can aid in detecting tornadoes.
• Red and purple on radar indicate strong returns and intense precipitation.

Thermometers

• Thermometers measure air temperature.
• Liquid-in-glass thermometers, using mercury or red-dyed alcohol, are common for surface air temperature.
• When air warms, the liquid expands and rises in the tube.
• Temperature impacts water's state: below 32°F (0°C) water is solid, above it is liquid.
• Water evaporates/boils at 212°F (100°C).
• Water vapor holds heat, meaning Earth's surface temperature directly relates to water.
• The coldest temperature, -128.6°F (-89.2°C), was recorded in Antarctica in July 1983.
• The warmest temperature, 134.1°F (56.7°C), was recorded in Death Valley, California, in 1913.

Computer Models

• Computer models analyze incoming weather data to interpret patterns for short and long-range forecasts.
• Computer forecasting is called numerical weather prediction (NWP).
• NWP uses mathematical equations with variables like temperature, pressure, and moisture.
• Computers calculate how these variables change over time, typically for 12-48 hour periods.
• Weather forecasting uses probability, such as researching past snowfall occurrences on New Year's Eve in NYC.
• Mid-latitude forecasting is challenging due to temperature variations.
• Meteorologists use four classifications of weather forecasts: short-range, medium-range, long-range, and hazardous weather forecasts.

Types of Weather Forecasting

• Short-range forecasts predict weather 12-48 hours ahead.
• Medium-range forecasts (MRF) predict the atmosphere 132 hours ahead, or 3-7 days.
• Long-range forecasts are probability-based regarding temperature and precipitation (below, at, or above normal).
• These are given 8-14 days out, monthly, and seasonally.
• Hazardous weather forecasts are statements from the NOAA/NWS Storm Prediction Center (SPC) for severe weather within a seven-day window.

Examples of Hazardous Weather Forecasting

• The Storm Prediction Center (SPC) aims to provide data on tornadoes, severe thunderstorms, lightning, wildfires, and winter weather.
• Meteorologists monitor forecasts and data for potential severe weather.
• If conditions favor severe weather, a watch is issued, and local weather services, news, and EMS personnel are notified.
• A warning indicates imminent severe weather (tornado, thunderstorm, tsunami) and is issued upon visual confirmation or radar detection.
• Early detection via these forecasts enables preparation and seeking safe locations.

Discover the science and tools behind weather forecasting. Learn how meteorologists predict atmospheric conditions using data, technology, and observation. Understand the importance of weather forecasts in daily life, long-term planning, and preparing for severe weather events.