2C WX - Aviation WX Charts

Question 0

2. What is a radar summary chart? (AC 00-45)

Answer 0

This is a computer-generated graphical display of a collection of automated radar weather reports, available hourly with a valid time of 35 minutes past each hour. Displays areas of precipitation as well as information about type, intensity, configuration, coverage, echo top, and cell movement of precipitation (and severe weather watches, if in effect when the chart is valid). It aids in preflight planning by identifying general areas and movement of precipitation and/or thunderstorms; however, it displays drops or ice particles of precipitation size only—it does not display clouds and fog. Therefore, since the absence of echoes does not guarantee clear weather, and cloud tops will most likely be higher than the tops of the precipitation echoes detected by radar, the radar summary chart must be used along with other charts, reports, and forecasts for best effectiveness.

Question 1

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1. What is a surface analysis chart? (AC 00-45)

Answer 1

This is a computer-prepared chart transmitted every three hours that covers the contiguous 48 states and adjacent areas. Provides a ready means of locating pressure systems and fronts. It also gives an overview of winds, temperatures and dew point temperatures at chart time. Since weather moves and conditions change, using the surface analysis chart along with other weather information gives a more complete weather picture.

Question 2

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3. What information does a weather depiction chart provide? (AC 00-45)

Answer 2

A Weather Depiction Chart contains a plot of weather conditions at selected METAR stations and an analysis of weather flying categories (IFR, MVFR,VFR). It is primarily a briefing tool to alert pilots to the location of critical or near-critical operational minimums at terminals in the conterminous U.S. and surrounding land areas. The chart is issued eight times daily starting at 0100 UTC.

Question 3

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4. What information do short-range surface prognostic charts provide? (AC 00-45)

Answer 3

Short-range surface prognostic (prog) charts provide a forecast of surface pressure systems, fronts and precipitation for a two-day period. The forecast area covers the 48 contiguous U.S. states, the coastal waters and portions of adjacent countries. The forecasted conditions are divided into four forecast periods: 12, 24, 36, and 48 hours. Each chart depicts a “snapshot” of weather elements expected at the specified valid time.
Additional prog charts are available for the low-level (surface–FL240), mid-level (10,000 ft MSL–FL450), and high-level (FL250–FL630) altitudes.

Question 4

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5. What is a convective outlook chart? (AC 00-45)

Answer 4

This chart depicts areas forecast to have the potential for severe (tornado, wind gusts 50 knots or greater, or hail 3⁄4-inch diameter size or greater) and non-severe (general) convection and specific severe weather threats during the following three days. The chart defines areas of slight risk (SLGT), moderate risk (MDT) or high risk (HIGH) of severe thunderstorms for a 24-hour period beginning at 1200 UTC. The Day 1 and Day 2 Convective Outlooks also depict areas of general thunderstorms (GEN TSTMS), while the Day 1, Day 2, and Day 3 Convective Outlooks may use SEE TEXT for areas where convection may approach or slightly exceed severe criteria.