Weather Forecasting and Prediction

Methods of Forecasting  Step 1 - Outside!  Step 2 - Satellite maps  Step 3 - Radar imagery  Step 4 - Surface and upper air maps  Step 5 - Computer models  Step 6 - Forecast experience/education

Step 1 – What’s Happening Outside  Cloud Types (High, Middle, Low, Cloud Cover)  Sunshine  Temperature  Winds (Direction, Speed)  Dewpoint (How Sticky Is It)  Precipitation (Rain, Snow, Sleet)  Lightning and Thunder

High Clouds  A Sign of Upper Level Moisture, Precipitation or Storms Possible within 24 Hours

Middle Clouds  If Seen In Morning with Vertical Development, Possibility of PM T-storms

Low Clouds  Usually Little Precipitation (Drizzle, Light Rain, Snow Shower)

Cumulonimbus – Thunderstorms Approaching

Local Observations  Metar Reports  KLNS Z 02008KT 9SM -RA BKN015 OVC024 14/13 A2984 RMK AO2 RAB50 SLP104 P0000 T  First the station, then the date and time (Z = GMT), then the wind direction (first three digits) and speed (last two digits) and the abbreviation KT for knots. Then the visibility, in SM (statute miles), the present weather (if any), and the sky cover. The two numbers separated by a slash are the temperature and dew point, in Celsius. Then comes the altimeter setting, in hundredths of an inch of mercury, preceded by an A. Finally comes the remarks.

Step 2 – Satellite Maps  We Have Satellites That Orbit Around the Earth and Take Photos of The Clouds  There are Several Types of Satellite Pictures –Visible (Shows Land, Water, Clouds) –Water Vapor (Shows Atmospheric Water Vapor) –Infrared (Bounces Radiation Off Clouds, Can See Fog and Snow Cover)

Visible Satellite Image

Water Vapor Satellite Image

Infrared Satellite Image

Radar Imagery  Nexrad (Next Generation Radar)  150+ Doppler Radars  Detects Precipitation  Wind Direction and Velocity  Radar Dish Sends Out Pulse Which Bounces Off Clouds and Precipitation and Returns Back to the Dish

Surface and Upper Air Maps  Shows Features (High Pressure, Low Pressure)  Wind Direction and Velocity  Heights of Pressure Levels  Temperatures

Computer Models  Take Mathematical Formulas and Climatology Data and Predict What Will Be Going On In the Atmosphere  Predictions Out to 16 Days, However, Best Data Within 3-7 Days  NAM (North American Model)  GFS (Global Forecast System)  European, Canadian, + Many More

Forecast Experience/Education  Know Geography and Climate of the Area You are Forecasting  Understand Forecast Model Trends  Remember the Weather Can Change at Any Moment without Warning  Understand the Processes That Occur In The Atmosphere