Preflight - Aviation Weather Charts Flashcards
Give examples of weather charts you will use during the flight planning purposes
Surface Analysis chart Weather Depiction chart Significant Weather Prognostic chart Short-Range Surface Prognostic chart Convective Outlook chart Constant Pressure Analysis chart Freezing Level Graphics
What is a surface analysis chart?
Analyzed chart of surface weather observations depicting:
- Sea level pressure - Location of High/Lows or Ridges/Troughs - Location of Fronts - Drylines/Outflow boundaries - Convergence lines
What information does a weather depiction chart provide?
Plot of Wx conditions at METAR stations to show flight category (VFR,MVFR,IFR)
Issued 8 times daily
Define the terms: LIFR, IFR, MVFR, and VFR.
LIFR: Low IFR, ceiling less than 500’ and/or less than 1 mile vis.
IFR: Ceiling 500’ to 1,000’ and/or 1 to 3 miles vis.
MVFR: Marginal VFR ceiling 1,000’-3,000’ and/or 3-5 mile vis.
VFR: Ceiling greater than 3,000’ and 5 miles vis. with clear skies
What are Short-Range Surface Prognostic charts?
Provide a forecast of:
-Surface pressure systems
-Fronts
-Precipitation
Issued for a 2 1/2 day period (12, 18, 24, 48, 60 hours)Describe a U.S. Low-Level Significant Weather Prog chart.
SIGWX provides a forecast of:
- Aviation Wx hazards - FL240 and below - Issued 4 times daily (12 and 24 hour)
Describe a Mid-Level Significant Weather (SIGWX) chart.
Provides a forecast of
- Significant enroute Wx Phenomena - 10,000' to FL450 - Issued 4 times daily in 24 hour periods
What information may be obtained from a U.S. High-Level Significant Weather Prog chart?
Provides a forecast of:
-Significant enroute Wx Phenomena
-FL240- FL630
Typically includes:
-TS
-Cumulonimbus clouds
-Moderate/severe turbulence/icing
-Tropopause heights
-Tropical cyclones
-Severe Squall lines
-Volcanic eruption
-Widespread sand/dust stormWhat is a convective outlook chart?
Issued for the following 8 days
-Probability thresholds for 1 to 3 days
-Probability thresholds for 4 through 8 days
-Days 1-3 show TSTMS
Shows area of risk categorized as severe to non severe:
-Marginal (MRGL)
-Sight (SLGT)
-Enhanced (ENH)
-Moderate (MDT)
-High (HIGH)
What are constant pressure analysis charts?
Shows upper air areas of equal pressure in the atmosphere. Helps pilots predict trends across the lines of pressure
Issued 2 times a day:
-850mb or 5,000'
-700mb or 10,000'
-500mb or 18,000'
-300mb or 30,000'
-200mb or 39,000'Describe a constant pressure level forecast.
Provide an overview of weather patterns at specified times and altitudes
Issued 4 times daily showing:
-winds/temperature aloft
-lows/troughs: clouds and precipitation
-highs/ridges: fair weather
-Location and strength of jet stream at 300mb/250mb/200mb
What significance do height contour lines have on a constant pressure chart?
Height of pressure identified by solid lines called contours showing:
-Highs/ridges
-Lows/troughs
Closer spaced contours/isobars = higher winds
What significance do isotherms have on a constant pressure chart?
Shown by dashed lines at 5°C intervals to show horizontal temperature variation chart altitude. Can determine if flying into colder/warmer weather
Subfreezing with temperature/dew-point spread of 5°C suggest icing
What is the significance of the isotach lines on a constant pressure chart?
Lines of constant wind speed on 300mb/200mb charts. Separate higher and lower wind speeds and used to map variation in wind.
- Shown in 20 knot intervals starting at 10 knots - Closer spaced isotach = higher winds - Very strong winds highlighted by hatches
What information does a freezing level graphics chart provide?
Assess lowest freezing level heights and values
Initial and 3- hour chart are updated hourly. The 6-,9-,12- are updated every 3 hours showing:
Color in 100s’ MSL of lowest freezing levels
