Weather Forecasts and Prognostics Flashcards
What freq should you obtain an En Route Flight Advisory Service below FL180?
122.0
EFAS can be obtained on 122.0 for AC flying below FL180.
Which weather forecast describes prospects for an area coverage of both severe and general thunderstorms during the following 24 hours>
Convective outlook
Day 1 is issued 5 times per day, Day 2 is issued 2 times per day, and the Day 3 is issued once per day.
Low-Level Significant Weather Prognostic Chart depicts weather conditions
That are forecast to exist at a valid time shown on the chart
Conditions at specified valid times.
The severe weather outlook chart depicts
or
The Severe Weather outlook chart which is used primarily for advanced planning, provides what information?
Areas forecast to have thunderstorms
A 24 hour severe weather outlook for possible thunderstorms
The Severe Weather Outlook chart (now called Convective Outlook) indicates scere storm risk areas in three varieties using labels, SLGT (slight) , MDT (moderate), and HIGH. General nonsevere thunderstorms are outlined but no label on map.
What weather conditions are depicted within the area indicated by arrow F?
Occasionally embedded CB, bases below 24,000 feet with tops to FL480.
An area of CB clouds, meeting select criteria is enclosed by scalloped lines. OCNL EMBD CB indicates 1/8 to 4/8 cloud coverage. 480/XXX indicates the tops at FL 480 and bases below FL240
What are the numbers inside a small rectangle on a High Level Sig. Weather Prog Chart mean?
The height of the tropopause in hundreds of feet above MSL.
Going upward from the surface, it is the point where air ceases to cool with height, and becomes almost completely dry. More formally, the tropopause is the region of the atmosphere where the environmental lapse rate changes from positive, as it behaves in the troposphere, to the stratospheric negative one. (Wiki)
SIGMET are issued as a warning of weather conditions potentially hazardous
to all aircraft
Advises of nonconvective activity that is potentially hazardous to all aircraft
What is the standard lapse rate of temperature?
2*C per 1,000’.
Hazardous Inflight Weather Advisory Service (HIWAS) is a continuous broadcast over selected VORs of
SIGMETS, CONVECTIVE SIGMETS, AIRMETS, Severe Weather Forecast Alerts (AWW), and Center Weather Advisories and urgent PIREPs
Wind Sheer advisories are NOT included in HIWAS
Area forecasts included a forecast period of 18 hours and cover a geographical
area of land of several states
18 hours forecast period
On a low level significant weather prog chart, if an area if ciricled with a solid line, that indicates what?
IFR conditions - ceilings less than 1,000 feet, and or visibility less than 3 miles
Decode the excerpt from the Winds and Temperature Aloft Forecast (FD) at 39,000’ – 830558
Wind 330* at 105knots, temp -58*C
“If a wind direction is coded between 51 and 86, the wind speed is 100knots or greater. To decode, subtract 50 from the direction and add 100 knots to the speed.
“830558” is 83-50=33(0), 05+100 = 105 knots, and -58*C
When is the temperature at one of the forecast altitudes omitted at a specific location or station in the Winds and Temperatures Aloft Forecast (FD)?
Fore the 3,000 foot altitude (level) or when the level is within, 2,500 feet of station elevation.
In the FD, no temps are forecast for the 3,000’ level or any level within 2,500 of station elevation
When is the wind group at one of the forecast altitudes omitted at a specific location or station in the Winds and Temperatures Aloft Forecast (FD)? When the wind..
is at the altitude is within 1,500 feet of the station elevation.
What weather conditions are depicted within the area indicated by arrow B?
Moderate turbulence from below 24,000’ MSL to 37,000’ MSL
Areas of moderate or greater turbulence are enclosed by bold dashed lines.
The hat symbol indicates moderate turbulence.
The number 370/XXX identifies a layer of turbulence form below FL240 to FL370
WND in the categorical outlook in the Aviation Area Forecast means that the wind during that period is forecast
is at least 20 knots or stronger
WND is included in the categorical outlook if winds, sustained or gusty, are expected to be 20 knots or greater
The body of a Terminal Aerodome Forecast (TAF) covers a geographical proximity within a
5 statute mile radius from the center of an airport
A TAF is a concise statement of the expected meterological conditions within a 5SM radius from the center of an airports runway complex during a 24-hour time period.
When are severe weather watch bulletins (WW) issued?
Unscheduled and issued as required.
What does a Convective Outlook (AC) describe for a following 24 hour period?
General thunderstorm activity
The U.S. Low Level Significant Weather Surface Prog Chart indicates tthat the northwestern Colorado and Eastern Utah can expect what?
moderate or greater turbulence from the surface to FL240
Inside the dashed line, can expect moderate or greater turbulence. The hat symbol with the 240 under it indicates that the turbulence will be from the surface and up to 24,000’.
A station is forecasting wind and temperature aloft at FL390 to be 300* at 200 knots; temp -54*C. How would this data be encoded in the FD?
809954
If the wind is over 200 knots, it is coded as 99 and 50 is added to the wind direction. 30+50=80. Wind is 8099. The temperature above 24,000’ is always negative and the minus sign is omitted.
Where does a High Level Sig Prog Chart base its altitude at?
/FL240
What approximate wind direction, speed, and temperature (relative to ISA) should a pilot expect when planning for a flight over PSB at FL270?
24,000
2368-26
30,000
7819-39
225* true at 93 knots; ISA +6*C
For FL270, interpolate between 24,000’ and 30,000’ (see info below). Standard temperature lapse rate is 2*C/1,000’. Given FL270; 27x-2=-54*C. -54*C+15*C (ISA at sea level)= -39*C. -33*C is 6* warmer than -39*C for ISA+6*.
“If a wind direction is coded between 51 and 86, the wind speed is 100knots or greater. To decode, subtract 50 from the direction and add 100 knots to the speed.
“830558” is 83-50=33(0), 05+100 = 105 knots, and -58*C”
PSB
24,000
2368-26
- Wind: 230
- Speed: 68 knots
- Temp 26*
30,000
7819-39
- Wind: 280
- Speed: 119knots
- Temp: -39*
AIRMET’s are issued on a scheduled basis how often?
Every 6 hours.
Which meteorological condition is issued in the form of a SIGMET (WS)?
Widespread sand or dust storms affecting at least 3,000 square miles or an area deemed to have a significant effect on the safetly of aircraft operations
One criteria for a non-convective SIGMET is widespread sand or dust storms affecting at least 3,000 square miles or an area deemed to have significant effect on the safety of aircraft operations.
What is the maximum forecast period of AIRMET’s
6 Hours
The maximum forecast period for AIRMETs are 6 hours
Which forecast provides specific information concerning expected sky cover, cloud tops, visibility, weather, and obstructions to vision in a route format?
249 TWEB 252317
A TWEB route forecast is for a 50nm wide corridor along a line conecting the end points of the route. It describes specific information regarding the forecase weather along the specified route.
How is wind calm shown on a TAF?
00000KT
5 digit readout group.
“VRB” wind entry in a TAF wil lbe indicated when the wind is what?
3 knots or less
A station is forecasting wind and temps aloft at FL390 to be 300* at 200 knots; temp -54*C. How would this data ba encoded in the FD?
809954
If the wind speed is over 200 knots, it is coded as 99 and 50 added to the wind direction. 30+50=80. Wind is 8099. The temperature above 24,000’ is always negative and the minus sign is omitted.
On the Convective Outlook chart, general thunderstorms are shown by an outline of what?
Solid outline without text indication of risk level.
Which values are used for winds aloft in forecasts? Magnetic or true direction?
True direction and knots.
In relation to true noth. Not magnetic.
