Radar Tutorial
Chapter 2, Page 3: And More Velocity Radar
Here is the reflectivity radar loop of the same event 28 minutes later. Notice the tornadic cell has moved into Kanabec
County and tracks across the northern edge of the County and into Pine County around Sandstone.
Here the cell looks decidedly HP in nature. The rain-free base seems to disappear on the image as more and more rain
wraps around it.
Here too, this cell produced several tornadoes some of which did F3 damage. This is a rare event in Minnesota.
Notice the trailing cell tracking over Morrison County into Mille Lacs north of Milaca. It is taking on a supercell
v-notch shape and has pretty intense rain fall as well.
Here is the velocity image loop for the same time period. Notice the small couplet right on the Mille Lacs/Kanabec County
border. There dark green and dark red come very close together and remain obvious as it tracks across Kanabec County. As
it nears the Pine County border the couplet seems to loosen up and dissipate.
Notice that the following cell is indeed rotating. It appears to be a classic supercell. An obvious couplet develops as
it moves east through Morrison County and then dissipates. This cell may well have looked suspicious to spotters, but
there were no reports of severe weather.
As I said before velocity radar is not a stand alone tornado detector. As the radar signal gets farther from the site,
it detects velocity higher and higher in the atmosphere. Velocity radar has an effective range of around 150 miles at
best. In fact, since many if not most tornadoes are formed from lower level circulation, such tornadoes may not be
detectable from much lower ranges.
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