What information is contained in a surface prognostic chart?
A prognostic chart is a map displaying the likely weather forecast for a future time. Such charts generated by atmospheric models as output from numerical weather prediction and contain a variety of information such as temperature, wind, precipitation and weather fronts.
How long are surface analysis charts good for?
Issuance & Validity: Issued every 3 hours. Valid Time (VT) of the chart on the lower left corresponds to the time of the observations. Valid time is given in UTC. Information is about 2-3 hours old.
What does a surface analysis chart tell you?
Surface analysis charts show locations of fronts, highs and lows, squall lines, dry lines, and other weather phenomena that are important in understanding current weather and predicting future weather events.
How long is a prognostic chart valid?
Valid for the time specified (12, 24, 36, 48 hrs) Data is forecasted. Information is insufficient for flight planning. An effective overview of observed and prognostic charts allow the many essential details to fit into place and have continuity.
What is the main reason for plotting a surface weather map?
Weather maps are created by plotting or tracing the values of relevant quantities such as sea level pressure, temperature, and cloud cover onto a geographical map to help find synoptic scale features such as weather fronts.
What do isobars show on a surface analysis chart?
Many of the surface analysis charts may contain thin solid lines to depict the features of the horizontal pressure field at mean sea level. These lines are called isobars and connect all points having the same sea level corrected barometric pressure.
What are isobars aviation?
Isobars are lines that connect locations having the same surface barometric pressure. They can tell a great deal about the weather at the surface, so knowing some isobar basics can help in preflight planning.
How often are low level significant prognostic charts?
Low altitude Significant Weather charts are issued four times daily and are valid at fixed times: 0000, 0600, 1200, and 1800 UTC. Each chart is divided on the left and right into 12 and 24 hour forecast intervals (based on the current NAM model available).