weather graphics

Graphic Weather Products & How to Read Them

Graphic Wx Products

• Quickly access large-scale weather patterns• Identify trends• Predict wx that might occur over time• Identify areas of IFR wx at a glance• See where IFR conditions are forecast within the

next 12-24 hours

Required Graphics

• Surface Analysis Chart• Weather Depiction Chart• Radar Summary Chart• 12/24 Hour Significant Weather Prognostic Chart• Winds & Temps Aloft Chart

Surface Analysis

Surface Analysis• Depicts an analysis of the current surface

weather• Computer prepared every 3 hours• Shows;

o Areas of pressureo Frontso Temperatureso Dew pointso Wind Directions & Speedso Local Weathero Visual Obstructions

Station Model

• Created by computer• Mainly on surface-

weather maps• Winds are true

direction• Temp/Dew point is in

Fahrenheit

So What Do I Need To Know?

• A good source for general weather information over a wide area.

• Depicts the actual position of fronts, pressure patterns, temperatures, dew point, wind, weather, and obstructions to vision at the valid time of the chart.

• When the Isobars are close the pressure gradient is greater meaning wind velocities will be stronger.

• Dashed lines indicate a weak pressure gradient.

Weather Depiction

Wx Depiction• Derived from METAR’s• Prepared every 3 hours beginning at 0100Z by a

computer• Used for flight planning• Displays

o Major frontso Areas of pressureo Graphic display of IFR, MVFR, VFRo Shows a modified station model

Modified Station Model

• Sky Conditions• Cloud height or ceiling• Weather• Obstructions to visibility• Same as Surface Analysis

So What Do I need To Know?

• Some may be automated• Bases shown are the lowest layer

Radar Summary

Radar Summary (SD)• Computer generated• Published hourly, 35 minutes past the hour• Displays areas of precipitation as well as the

characteristics of the precipitation.

SD• NA – No information

Available• NE – No echoes• Height of tops in

hundreds of feet MSL• Movement of cells

depicted by arrow

So What Do I Need To Know?

• The only charts that show lines and cells of thunderstorms

• You can determine the tops and bases of echoes, the intensity of the precipitation, and the echo movement.

• Most effective when used in combination with other charts, reports, and forecasts.

Satellite Wx Pictures

Composite Moisture Stability Chart

• Four Panels showing stability, precipitable water, freezing level, & average relative humidity conditions.

• Computer generated• Obtained from upper air observations• Updated twice daily• Stability = Potential for thunderstorms• You will not find this chart anywhere in the

current system

Constant Pressure Analysis Chart

Composite Moisture Stability Chart

Low Level Significant Weather Prog Chart

Prog Charts

• SFC to FL240 (400 Millibar)• 12/24 hour forecast, and 36/48 forecast• Issued four times daily• Valid time is printed on it

Prog ChartsUpper Panels Lower Panels

• Shows forecasted significant weathero Non-convective turbulence

(dashed lines)o Freezing levels (zigzag lines)o IFR (solid lines)o MVFR (scalloped lines)

• Forecast surface wxo Pressure systemso Frontso Precipitation

High-Level Significant Weather Prog Chart

Issued 4 times a day

High level Prog• Domestic & International Flights• FL240 – FL600• Presents a forecast for;

o Thunderstormso Tropical cycloneso Squall Lineso Moderate or greater turbulenceo Wide spread dust storms & sandstormso Tropopause heighto Location of jet streamso Volcanic activity

Convective Outlook Chart

Convective Graphics

Conv. Outlook

• Issued five times daily• Convective Activity• Hail• Tornadoes• Winds

Hail

Tornado

Winds

Forecast Winds & Temperatures Aloft Chart

FD

• 12 hour forecasts valid at 0000Z & 1200Z daily• Read same as station model winds• 99 for calm winds with no arrow• Temps are shown in Celsius