VORTEX II: Day 27 (TORNADO!!!)
As I mentioned in yesterday’s post, it finally happened. The VORTEX II armada captured a tornado. They started out the day in Sterling, KS and were faced with the decision of staying in the same general area / heading slightly SE or heading up NE of the Cheyenne ridge. Field coordinator David Dowell and myself gave passionate arguments for targeting Wyoming which helped turn the tide…and this is what the armada did.
They started out by heading to Kimball, NE (which is in the far southwest county of the NE panhandle) and watched thunderstorms develop to their west. As the thunderstorms moved closer to the armada, it became clear that the southern most storm had developed supercellular characteristics. After a brief discussion, the armada decided to make this the target storm and they deployed on it. As they approached the storm from the east, the National Weather Service office in Cheyenne, Wyoming issued a tornado warning on the storm. While the storm was not producing a tornado at that precise moment, the storm certainly looked like it was getting ready to produce one. The Weather Channel broke in to their regularly scheduled program began streaming live video of the supercell thunderstorm.
As the armada sent probes 1, 2, and 3 into the region of the thunderstorm that was about to produce the tornado, very large hail began to fall on the vehicles. In fact, probes 1 and 3 received so much hail that the damage forced them to abandon all other missions for that day. They were forced to stay behind the armdada and have their windows repaired.
While the probes were being pelted by hail greater than 4.50″ (softball size), the supercell began to develop a rapidly rotating wall cloud that went on to produce a tornado (carried live by the Weather Channel). The storm was sampled from start to finish by the armada (and The Weather Channel).
Once the tornado dissipated, the armada tried to reposition themselves to try and observe any additional tornadoes that might develop. This proved a difficult task due to the poor road network and storm motion. Fortunately for the armada, the storm did not produce an additional tornado, so they didn’t miss one due to poor roads.
When operations where finally called off, the armada had a long drive back to their hotel (Kearney, NE). To make matters worse, the storms they had been targetting all day had grown together and formed what is known as a Mesoscale Convective System (MCS; really just a really big cluster of thunderstorms interacting and aiding one another). This MCS repeatedly had transient rotational signatures, extremely large hail, and damaging winds that tracked all along the roads the armada needed to travel in order to reach their hotel. Because of this, I kept the VORTEX II Operations Center open until after 1 AM CDT. I’m happy to report that every vehicle made it back safely…except probes 1 and 3 which were forced to stay in Cheyenne for repairs.
The tornado was preliminarily rated an EF-1 on the Enhanced Fujita scale. For more information, including pictures of the tornado, please visit the NWS Weather Forecast Office in Cheyenne, WY
