Penn State Weather Camps Basic Weather Forecasting Guidelines Sat I Sat I - Sat II - Radar -Sat II Radar sfc. map 1 sfc. map 1 - sfc. map 2 – sfc map 3sfc. map 2sfc map 3

Basic Forecast Guidelines Persistence Forecast = yesterday’s valuesyesterday’s values Radar derived precipitation

Know what to expect! = Climo. PSU … June 15 data

Basic Forecast Guidelines Climatology Forecast = averages for today Persistence Forecast = yesterday’s valuesyesterday’s values

Basic Forecast Guidelines What causes temperature to change? ◦Cloud cover:  Day Vs. Night ◦Precipitation:  When it rains T’s tend to be higher/lower? Why? ◦Wind and Fronts:  Direction ◦ N vs. S  Speed ◦ Day Vs. Night

Basic Forecast Guidelines What causes rain? ◦Need clouds!  Will any ole cloud do? ◦Moisture supply  Bodies of water – Moisture content of air ◦Upward motion:  How does this affect clouds/precip.?  Mechanisms for “lift” ◦ Fronts – Topography – Low Pressure – Jet stream dist. ◦(In) stability:  Warm down low … cold up high!

Basic Forecast Guidelines Extrapolation/trend Forecast = Look upstream to see what’s coming! ◦Sat IR - Sat II - Sat VIS - Radar - sfc. map 1 - sfc. map 2 – sfc map 3Sat IR Sat II Sat VIS Radarsfc. map 1 sfc. map 2sfc map 3 Thunderstorms/Moist Convection ◦Triggers ? ◦Fuel  LI LI  Cape – Cape fcst CapeCape fcst

Basic Forecast Guidelines The “Models” ◦Simulate future state of atmosphere ◦Higher resolution / lower resolution The “Models” ◦Lower Res. (GFS)Lower Res. (GFS) ◦Higher Res. (GFS)Higher Res. (GFS) ◦Higher Res. (NAM)Higher Res. (NAM) ◦Higher Res. (HRRR)Higher Res. (HRRR)

Your competition !!! ◦The National Weather ServiceThe National Weather Service ◦The Weather ChannelThe Weather Channel ◦AccuweatherAccuweather ◦The guy or gal to your left and right