Definition
False radar returns that appear on a NEXRAD weather display as straight lines or spikes radiating outward from a radar site, caused by the radar antenna detecting electromagnetic energy from the sun when the sun aligns with the antenna's scanning beam at sunrise or sunset. They are a known display artifact, not actual precipitation or weather.
Plain English
Fake weather streaks on a radar picture caused by the radar pointing toward the sun. The lines look like weather but are not, so pilots should ignore them when planning around real weather.
Context Anchor
Seen when reading NEXRAD weather on an electronic flight display or multi-function display, especially in discussions of NEXRAD display errors and abnormalities.
Derivation
Called 'sun strobes' because they appear as bright, straight, strobe-like lines on the display, caused by the sun. The name describes both the appearance (a thin radiating streak) and the cause (solar interference).
Why Pilots Care
They may be mistaken for heavy weather, prompting unneeded route changes or altitude adjustments.
Analogy
Sun strobes are like glare in a photo. The bright streak in the picture is caused by the sun hitting the camera, not by a real object in the scene.
Intuition Check
Sun strobes are not aircraft strobe lights, and they are not a kind of weather. They are false marks on a weather-radar image caused by the sun.
Example Sentence 1
The pilot noticed a thin red line on the NEXRAD display pointing east at sunrise and recognized it as a sun strobe rather than a line of thunderstorms.
Example Sentence 2
NEXRAD sun strobes appeared on the display shortly after sunrise and faded once the sun moved past the radar site.