FAA TFR List

Weather Links

The Weather Channel

The Weather Channel - Ann Arbor

Aviation Digital Data Service - Pireps, Notams, TAFs and METARs

National Weather Service - Aviation Weather Center

intellicast.com - Weather for Active Lives

www.duat.com - for Weather Briefings

www.duats.com - for Weather Briefings

CAPE / CIN Charts

Unisys Weather - K Index Plot

Ohio State University K Index Plot

A K-Index of 0 is very dry air and thus if the air is lifted there will be very little chance that clouds/precipitation will form due to adiabatic cooling. Thus very little heat will be released to the atmosphere when this occurs. This means that the atmosphere will tend towards greater stability.

When the K-Index is 20 to 40; the atmosphere is getting very wet and is set to create a lot of clouds/precipitation upon lifting from adiabatic cooling. Once the clouds form (called the lifted condensation level) heat will start being released to the atmosphere (latent heat of condensation) driving the atmosphere towards instability.

Unisys Weather - Lifted Index Plot

Ohio State University Lifted Index Plot

The Lifted Index directly measures the instability of the atmosphere. The atmosphere is unstable when the Lifted Index is posting negative numbers, say 0 to -4 (a very unstable atmosphere). Lifted Index readings that are positive 0 to 5, 10, 15, etc. indicate a stable atmosphere.

However, an unstable atmosphere may not produce weather if the air is very dry. Conversely, a stable atmosphere that has a lot of moisture can quickly change particularly if there is a strong lifting mechanism. Strong convective lifting from the sun in the summertime; frontal lifting often called frontal wedging; orographic lifting from strong surface flow up rising terrain such as along mountainous areas are all examples of lifting mechanisms.

Unisys Weather - Current Satellite Surface Map

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