The High Energy Laser Mobile Demonstrator -- mercifully shortened to HEL MD -- is a futuristic laser weapon that scoffs in the face of inconveniences such as fog and rain to destroy whatever it's supposed to destroy. The US Army has shown the weapon to be able to successfully lock onto and take out targets in laser-unfriendly conditions involving fog and rain.
The HEL MD is a trailblazing mobile, high-energy laser. It consists of a 10-kilowatt high-energy laser mounted on an Oshkosh tactical vehicle, and capable of tracking and obliterating a wide variety of targets.
Boeing has unsurprisingly not revealed too many details about this military war monster, but it is believed that it likely uses a reference beam to probe through the fog, before focusing a separate weapon beam onto the target.