What is the role of Doppler radar in tornado forecasting?
Each NWS forecast office uses output from at least one Doppler radar in the area to help to determine if a warning is needed. Doppler radar signatures can tell warning meteorologists a great deal about a thunderstorm’s structure, but usually can’t see the tornado itself. This is because the radar beam gets too wide to resolve even the biggest tornadoes within a few tens of miles after leaving the transmitter. Instead, a radar indicates strong winds blowing toward and away from it in a way that tells forecasters, “An intense circulation probably exists in this storm and a tornado is possible.” Possible doesn’t mean certain, though. That is why local forecasters must also depend on spotter reports, SPC forecast guidance on the general severe weather threat, and in-house analysis of the weather situation over the region containing thunderstorms, to make the best-informed warning decisions.
