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Winds aloft, officially known as the winds and temperatures aloft forecast, (known as "FD" in the US and Canada, but becoming known as "FB", following the World Meteorological Organization [WMO] nomenclature), is a forecast of specific atmospheric conditions in terms of wind and temperature at certain altitudes, typically measured in feet (ft) above mean sea level (MSL).
In the past, and sometimes today, a theodolite was used to track the balloon in order to determine the speed and direction of winds aloft. [1] The principle behind the ceiling balloon is that timing of a balloon with a known ascent rate (how fast it climbs) from its release until it disappears into the clouds can be used to calculate the height ...
In meteorology the Ellrod index is a technique for forecasting clear-air turbulence (CAT). It is calculated based on the product of horizontal deformation and vertical wind shear derived from numerical model forecast winds aloft.
Winds circle anti-clockwise around lows in the northern hemisphere, and clockwise in the southern hemisphere, due to opposing Coriolis forces. Low-pressure systems form under areas of wind divergence that occur in the upper levels of the atmosphere (aloft). The formation process of a low-pressure area is known as cyclogenesis.
Coder/decoder CofA Certificate of airworthiness: COMM or COM Communications transceiver, Communications receiver, or Communications radio transmitter: Now, normally: either VHF or UHF; HF communications avionics are usually abbreviated simply HF CORSIA Carbon Offsetting and Reduction Scheme for International Aviation: COTS Commercial off-the ...
Fronts are generally guided by winds aloft, but do not move as quickly. Cold fronts and occluded fronts in the Northern Hemisphere usually travel from the northwest to southeast, while warm fronts move more poleward with time. In the Northern Hemisphere a warm front moves from southwest to northeast.
There is a long history of theodolite use in measuring winds aloft, by using specially-manufactured theodolites to track the horizontal and vertical angles of special weather balloons called ceiling balloons or pilot balloons (pibal). Early attempts at this were made in the opening years of the nineteenth century, but the instruments and ...
AIRMET TANGO (Turbulence) moderate turbulence, sustained surface winds of 30 knots or greater, and/or non convective low−level wind shear. AIRMET ZULU (Icing) Moderate icing and provides freezing level heights. For an authority to issue an AIRMET, applicable conditions must be widespread.