High and Low Pressure Forecast

H = High pressure (trade winds, nice cool air, blue sky, sunshine and good weather)

L = Low pressure (warm humid air that brings cloudy sky and rain showers)

General Information

-High Pressure:

Clear Skies

Light Winds

Settled Weather

Isobars are quite far apart

Travel clockwise in Northern Hemisphere

-Low Pressure:

Strong Winds

Heavy Rains

Unsettled Weather

Isobars are close together

Travel counter clockwise in southern Hemisphere

-Cold Front: Blue Line with triangle on it

-Warm Front: Red Line with half circles on it

-Occludded Front: Purple Lines with triangles & half circles on it Occurs when a cold front catches up to see warm front Clouds & Rainfall

-Weakening Warm front: Red half circles & triangles separated by an X A front that is starting to dissipate Cloud & Rainfall start to disappear

-Trough: Thick black line Increasing cloud cover & increase chance of rain

A long area of low surface pressure

-Average Sea Level pressure is 1013 MB.

Below 1013 is low pressure & above is high pressure

Hurricane, Typhoon and Cyclone Storms

Category 1 winds 74-95 mph surge 3-5 feet

Category 2 winds 96-110 mph surge 6-8 feet

Category 3 winds 111-130 mph surge 9-12 feet

Category 4 winds 131-155 mph surge 13-18 feet

Category 5 winds 155+ mph surge 19 feet or higher