TERMINOLOGY Flashcards
Adiabatic cooling.
A process of cooling the air through expansion is better known as…
ADVECTION FOG
Answer: Forms day or night as a result of moist air moving over a cold surface.
Atmospheric Pressure?
Answer: It is the force per unit area exerted by the weight of the atmosphere.
BROKEN BKN
BKN (5/8 to 7/8 coverage) and
CLOUDS FEW
FEW (1/8 to 2/8 coverage),
CLOUDS OVERCAST OVC
OVC (8/8 coverage).
CLOUDS SCATTERED SCT
Answer: Scattered (SCT) is defined as 3/8 to 4/8 coverage.
COLD FRONT
Occurs when a mass of cold dense stable air replaces a warm mass of air. Typically rapid moving 25-30mph with extreme fronts moving up to 60mph. The rapidly ascending air causes the temperature to decrease suddenly, forcing the creation of clouds. The slope is typically characterized as being step which forces air to rise rapidly creating cumulonimbus clouds and dangerous weather.
Prior to the passage of a typical cold front, cirriform or towering cumulus clouds are present, and cumulonimbus clouds are possible. Rain showers and haze are possible due to the rapid development of clouds. The wind from the south- southwest helps to replace the warm temperatures with the relative colder air. A high dew point and falling barometric pressure are indicative of imminent cold front passage.
COLD FRONT
DURING: DROP IN TEMP, WIND BUILD UP AND SHIFT. HEAVY RAIN, HAIL, LIGHTNING.
AFTER: WIND SHIFT SHOWERS SUBSIDE. AIR PRESSURE RISES. VISIBILITY INCREASES. WIND SHIFTS FROM SW TO NW.
COLD FRONTS ABBREVIATED
cold fronts bring sudden storms, gusty winds, turbulence, and sometimes hail or tornadoes.
Cold fronts are fast approaching with little or no warning, and they make a complete weather change in just a few hours. The weather clears rapidly after passage and drier air with unlimited visibilities prevail. Warm fronts, on the other hand, provide advance warning of their approach and can take days to pass through a region.
CORIOLIS FORCE
CAUSED BY THE EARTH ROTATION IS WHAT GIVES WINDS WITHIN HIGH PRESSURE SYSTEM THERE CLOCKWISE CIRCULATION.
DEFINITION OF WINDSHEAR
Answer: Any rapid change in wind direction or velocity which causes airspeed changes greater than 15 knots or vertical speed changes greater than 500 feet per minute.
Diurnal variation?
Answer: It is the change in temperature from day to night brought about by rotation of the Earth.
HIGH PRESSURE - NORTHERN HEMISPHERE
CLOCK WISE OUT AND DOWN. TOWARD THE LOW
HIWAS
Hazardous Inflight Weather Advisory Service (HIWAS[1]) is a continuous broadcast of hazardous weather information which is transmitted over selected VORs. This hazardous weather includes AIRMETs, SIGMETs, Convective SIGMETs, Center Weather Advisories (CWAs), Severe Alert Weather Watches (AWWs), and urgent PIREPs.[2]
JET STREAM
Answer: The jet stream is a narrow band of strong wind (by arbitrary definition, it has wind speeds of 50knts or greater) meandering through the atmosphere at a level near the tropopause. The jet stream is always found at a vertical break in the tropopause where the tropical and polar tropopauses meet.
LOW PRESSURE -NORTHERN HEMISPHERE
COUNTER CLOCKWISE TOWARD THE CENTER. ACCUMULATING IN THE CENTER. FORCING AIR IN THE CENTER TO RISE. COUNTER CLOCK, IN AND UP.
LOW PRESSURE SYSTEM
Answer: Unstable and usually brings increasing cloudiness and precipitation.
low pressure system?
Answer: Air flows from areas of high pressure into areas of low pressure because air always seeks out lower pressure. In the northern hemisphere, the air flows toward a low and is deflected to create a counterclockwise or cyclonic circulation. The air flows into a low pressure area to replace rising air this air tends to be unstable, and usually brings increasing cloudiness and precipitation.
Microburst?
What is a dry microburst?
Answer: Microbursts are small-scale intense downdrafts which, on reaching the surface, spread outward in all directions from the downdraft center.
A dry microburst often generates a ring of dust on the surface. A microburst is defined if damaging winds extend to 2.2 miles or less horizontally.
MOUNTAIN WAVE
Answer: Mountain wave occurs when air is blown over a mountain range or ridge of a sharp bluff. Generally requires winds of 30 knots or greater but may occur with winds as little as 15 knots. Creates strong updrafts/ downdrafts on lee side which can cause turbulence up to 700 miles downrange. May form lenticular clouds over peaks.
Pressure Gradient force?
Answer: Pressure differences must create a force in order to drive the wind. The force is from higher pressure to lower pressure and is perpendicular to isobars or contours. This force is the pressure gradient force.
RADIATION FOG
Answer: Usually occurs; High humidity during the early evening. Cool cloudless nights with light winds. Favorable topography.
TERRESTRIAL RADIATION
Answer: The Earth radiates energy, this outgoing energy is terrestrial radiation.
