A stationary front is a weather front or transition zone between two air masses-one cold and one warm-where neither air mass is advancing into the other at a speed greater than about 5 knots (roughly 6 miles per hour) at the surface. This results in the front remaining nearly in the same position for hours or even days
Key Characteristics of a Stationary Front
- It forms when a cold or warm front slows down or when surface temperature differences cause little air mass movement, such as along a coast
- Winds on either side of the front usually flow nearly parallel but often in opposite directions
- The front is marked on weather maps by a line with alternating blue triangles pointing toward the warmer air and red semicircles pointing toward the colder air
- Although the front itself does not move much, warm air rises over the colder air, which can lead to cloudiness and prolonged precipitation if moisture is sufficient
- Weather along a stationary front can vary widely but often includes overcast skies, rain, or snow, sometimes heavy if the warm air is very humid
- Stationary fronts may eventually dissipate, transform into cold or warm fronts, or evolve into shear lines when temperature contrasts diminish
Weather Implications
- Because the front remains in place, it can cause extended periods of cloudy and wet weather.
- It can serve as a focus for storm development, including mesocyclones or even tropical cyclones if conditions are right
In summary, a stationary front is a boundary between warm and cold air masses that is essentially "stalled," causing persistent weather patterns in the affected area
