Isolated to scattered severe thunderstorms appear possible across portions of the Southeast and Carolinas on Saturday where a Slight Risk (Level 2 of 5) has been issued. A Slight Risk Excessive Rainfall Outlook (Level 2 of 4) has been issued for part of the northern Gulf Coast Saturday due to the threat of flash, urban, and riverine flooding. Read More >
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Density Altitude
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On a hot, muggy day, the air becomes “thinner” or less dense, and its density at a pilot’s location is equivalent to a higher altitude in the standard atmosphere. It is hazardous to aircraft during takeoff and climb because:
- Aircraft power is reduced. The engine will ingest less air to support combustion.
- Aircraft thrust is reduced. A propeller will have less "grip" on the air, while a jet engine will will exhaust less mass.
- Lift is reduced. The thinner air will exert less upward force on the airfoils.
As a result, a longer takeoff and landing roll is required, especially for a fully-loaded aircraft. After takeoff, the aircraft will have a smaller rate of climb and will have a lower service ceiling.
Density altitude is usually reported at each AWOS/ASOS station in the Remarks section of the METAR, if the value is greater than 1000ft higher than the elevation of the airfield. Here's an example:
METAR KMSY 291400Z AUTO 18006KT 10SM CLR 28/13 A3001 RMK SLP161 DENSITY ALT 1000FT
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