Backdoor cold front

For locations in the northern mid-latitudes, weather systems usually move from west to east. Usually, but not always.

A backdoor cold front is a weather boundary that moves south or southwest, bringing cool air from the east or northeast. Unlike typical cold fronts that push west to east, it arrives from an atypical direction—entering through the "back door." Source Credit: Backdoor cold front (Wikipedia).

On 12 July 2026, weather radar showed a backdoor cold front located over the mid-Atlantic United States.

RadarScope (app) animation beginning at 12:00 noon EDT.

The precipitation echoes moving from east-to-west (to the north) and west-to-east (to the south) trace an invisible boundary between different air masses -- that's the "backdoor" cold front!

RadarScope (app) animation beginning at 2:18 PM EDT.

Tech Tips

Set the RadarScope (app) "Radar Frame Count" for 30 frames, the maximum number of frames.

Settings / General / Data / Radar Frame Count

A 30-frame time lapse lasts ~25 to 30 minutes. That's not very long, so I recommend you set the preceding videos to Play in a "Loop."

Click the white "Play" button. When the button turns red, right-click on the video and select "Loop." Then press the "Play" button again and the video will loop over and over. Alternate procedure (for mobile devices): Click the "Settings" button; select "More options" then select "Loop."

Related Resources

• RadarScope app - available for both Apple iOS and Android operating systems
• backdoor cold front - AMS Glossary of Meteorology
• "Backdoor" Cold Front - National Weather Service Glossary
• Search results for "RadarScope app" tag from walter sanford's photoblog (4 posts)

Copyright © 2026 by Walter Sanford. All rights reserved.