Penn State Weather Camps

Basic Weather Forecasting Guidelines

Basic Forecast GuidelinesClimatology Forecast = averages for today

Persistence Forecast = yesterday’s values

Basic Forecast Guidelines

Climatology – Persistence – Modified Persistence

What causes temp 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 H20 – Moisture content of air (Td)◦Upward motion:

How affect clouds/precip.? Mechanisms for “lift”

◦Fronts – Topography – Low Pressure – Jet stream dist.

◦Intability (convection): Warm down low … cold up high!

Basic Forecast Guidelines

Climatology – Persistence – Modified Persistence

Extrapolation/trend Forecast = Look upstream to see what the wind’s bringing in !◦ Satellite IR - Satellite VIS - Radar - sfc. map 1 - sfc. map 2

Thunderstorms/Moist Convection◦Triggers ?◦Fuel

LI Cape

Basic Forecast Guidelines

The “Models” ◦Simulate future state of atmosphere◦Higher resolution / lower resolution

The “Models” ◦Lower Res. (GFS)◦Higher Res. (NAM)◦Higher Res. (HRRR)

Clouds Forecasting …◦Soundings◦Cloud forecasting I◦Cloud forecasting II – NAM◦Cloud forecasting II – HRRR

Your competition !!!

◦The National Weather Service

◦The Weather Channel

◦Accuweather

◦The guy or gal to your left and right