Weather Maps: This Assignment Will Help You Better Understan

Weather Mapsthis Assignment Will Help You Better Understand The Cyclog

Weather Maps This assignment will help you better understand the cyclogenesis and weather forecasting lessons, and provide a basis for better understanding of public weather forecasts and products in the future. Regardless of when you do this assignment, it is important to use information from roughly the same time, as comparing charts and images from different days and vastly different times of the same day are like comparing apples and oranges. So, when you do this assignment, set aside an hour or so to do it all at once…so that your surface map, radar, satellite, and upper air are all from the same day and close to the same time of day! To start, copy the following link: The current surface weather chart should pop up.

Click on the image beneath the words “surface data.” When it comes up, save it.

Questions and Analysis

1. What is the date/time of this chart (hint, upper left hand corner, in Greenwich Mean Time)?

The date and time of the surface weather chart are crucial for understanding the synoptic setup. In most surface maps, this information is located in the upper left corner and expressed in Greenwich Mean Time (GMT). Identifying this timestamp allows for accurate comparison with satellite, radar, and upper-air data, ensuring all observations are from the same time frame. For example, if the chart shows a date/time of 2024-04-27 1200 GMT, it indicates observations were taken at noon GMT on April 27, 2024.

2. Locate a cold front. What direction are the winds ahead of (east of) the cold front? How about behind (west of) the cold front?

On the surface map, a cold front typically appears as a line with blue triangles pointing in the direction of movement. Winds ahead of the cold front (east of it) are usually southerly or southeasterly, indicating warm, moist air being advected toward the front. Behind the cold front (west of it), winds tend to shift to northwesterly or westerly, carrying cooler, drier air into the region. This wind shift is characteristic of frontal passage and influences weather conditions significantly.

3. Is there any precipitation shown on the chart? If so, where? Is it along frontal boundaries?

Precipitation on surface weather charts is often indicated by shaded areas, symbols, or color overlays. Typically, precipitation is concentrated along frontal boundaries, especially along cold fronts, where warm moist air is lifted over colder air, leading to cloud formation and rain. The presence of precipitation along a frontal boundary suggests active weather, such as thunderstorms or steady rain, aligning with the dynamics of cyclogenesis. The chart may also show embedded convective activity within these zones.

4. Locate a High and a Low-pressure system and in words describe the location.

High-pressure systems are generally marked as "H" and low-pressure systems as "L" on the surface map. The high-pressure system is associated with descending air, clear skies, and relatively stable weather, often situated over continental or oceanic regions away from active fronts. Conversely, a low-pressure system signifies ascending air, cloud formation, and stormy weather, typically located near active frontal zones or troughs. Describing their positions relative to other features (e.g., "A low-pressure system is located over the southeastern United States, while a high-pressure ridge extends over the northwestern area") provides insight into regional weather patterns.

5. Copy the link to the infrared satellite image. How do the cloud features compare to the surface features?

Infrared satellite imagery depicts cloud top temperatures, with colder clouds appearing brighter white or blue, indicating higher altitude and potentially more severe weather. When comparing satellite images to surface maps, large cloud masses often correlate with low-pressure systems and frontal zones. For example, thick, cold cloud tops over a cyclone's center mirror the surface low-pressure area. Sometimes, satellite imagery reveals upper-level features such as jet streams or troughs not immediately evident at the surface, providing a more comprehensive understanding of atmospheric dynamics.

6. How do the radar precipitation features compare to the surface chart and satellite image?

Doppler radar provides real-time data on precipitation and storm movement, showing intensity and location of precipitation echoes. Comparing radar data with surface charts reveals how precipitative activity aligns with features like fronts and pressure systems—precipitation typically occurs along cold fronts and within cyclones. Radar images often show convective cells and rainfall intensity, which can be more localized than the broad frontal zones visible on surface and satellite images. Disparities may occur, for example, when satellite images display extensive cloud cover with no corresponding precipitation detected on radar.

7. Locate the upper air troughs and ridges that correspond to the surface high and low you analyzed, and describe how they match up or their relative positions.

Using the 500-mb chart, identify troughs (elongated regions of lower heights) and ridges (higher heights). Typically, upper-level troughs are located west or southwest of surface lows, supporting cyclonic development aloft, while ridges are situated over the high-pressure areas. Understanding the vertical structure involves noting whether the upper trough is east or west relative to the surface low—generally, the upper trough lies west of the surface low, with the surface low often located downstream of the upper trough. This vertical alignment reflects the dynamics of cyclogenesis, as upper-level disturbances induce surface cyclones through divergence and upward motion.

Conclusion

This exercise integrates multiple weather data sources to understand the complex processes driving weather systems and cyclogenesis. Comparing surface maps, satellite, radar, and upper air charts provides a layered perspective, revealing how atmospheric features are interconnected vertically and horizontally. Recognizing the patterns and relationships among these datasets enhances forecast accuracy and deepens understanding of atmospheric dynamics, ultimately improving communication of weather information to the public and decision-makers.

References

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