Reading the Skies: How Surface Maps Tell the Weather’s Story

Every weather system leaves clues on a surface map...temperature, wind, and pressure tell the story of what’s happening in the atmosphere at a given moment. During our WEAX 201 lab exercise, we analyzed two contrasting locations on November 26, 2019, at 1800Z: Lincoln, Nebraska, and St. George, Utah.

Lincoln, Nebraska: Inside the Low

At Lincoln, the surface station model showed a temperature of 35°F, a dew point of 32°F, and a sea-level pressure code of “039,” which converts to 1003.9 millibars. The wind barb indicated 15 knots from the northeast, and the weather symbol, two asterisks, represented moderate snow. The sky cover was completely overcast, confirming active weather within a low-pressure system. Moist air was rising, cooling, and condensing, producing steady snowfall as temperatures hovered near freezing.

St. George, Utah: Under the High

In contrast, St. George, Utah, was under a high-pressure system with surrounding isobars near 1020–1024 mb. The temperature was 36°F, and the dew point was 18°F, with winds from the northwest at 10 knots. The open circle on the station model indicated clear skies, typical of sinking air and dry conditions found under high pressure. The air was descending, limiting condensation and preventing cloud formation.

This comparison between Lincoln and St. George illustrates the relationship between air motion and weather type. Low pressure supports lift and precipitation; high pressure promotes sinking air and clearing conditions. Together, they define the dynamic balance that shapes daily weather and flight operations alike.

References

Ahrens, C. D., & Henson, R. (2022). Meteorology Today: An Introduction to Weather, Climate and the Environment (13th ed.). Cengage Learning.
Surface Analysis (NOAA, 2019). https://www.wpc.ncep.noaa.gov/

For students learning meteorology, using quality tools helps translate data into understanding. Adjustable LED desk lamps improve visibility when analyzing charts, and Grammarly ensures clear, professional lab reports.