Why Surface Weather Maps First Surface Weather

Why Surface Weather Maps?

First Surface Weather Map

The Telegraphic Communication Revolution

First Real-Time Weather Maps

Fronts

Fronts

Still Used Today

What is on surface charts?

Surface Observations are plotted using the station model

Station Model

Practice

Pressure Change over the Past 3 hr

Current Weather

Sky Coverage

Sky Obscured…you are in cloud

Wind Pennants

Wind Speed

You need to be able to read the station models

What kind of observations are plotted on surface charts?

Drifting Buoys

Isobars of sea level pressure are found on station map

Why use sea level pressure rather than station pressure— the pressure at the elevation of the barometer?

Terrain effects on pressure would swamp the meteorological signal

Example of Pressure Reduction

Pressure Reduction

Once the analysis is done, put on H’s and L’s

Winds and pressure

Will explain why in a few weeks

In the northern hemisphere winds tend to blow countclockwise around lows and clockwise around highs (opposite in the southern hemisphere)

Other features on surface charts

What are fronts?

Definition A front is a boundary between air of relatively uniform warm air and a zone in which temperatures cools rapidly

Four Main Types of Fronts

Warm Front

Stationary Fronts

Occluded Front (a hybrid)