That's not only impossible to gauge from the Base Reflectivity mode; but if these two REALLY were tornado chasers, driving directly into a tornado's path (just because it's ONLY a F1) is beyond foolhardy...as any experienced (and most inexperienced) chasers know.
I saw a movie the other night about tornado research (starred Nicole Kidman as the lead scientist), that was BEYOND ridiculous. She's in the chase vehicle....telling everyone about the "F4...maybe F5 tornado they are OBSERVING ON RADAR" -- when the screen she's clearly looking at is showing the satellite loop of a major HURRICANE.
No one in the atmospheric science/ meteorology is that stupid....and (hopefully) few in the theatre audience are that gullible. Even my seven year old nephew said "Uncle Perry, that's not a radar...it's a satellite". I replied "I know Nick...that movie is totally bogus, and she's (Nicole Kidman) an idiot"


I don't know about you'll, but if the storm chaser (or meteorologist) can't tell a tornado on radar from a hurricane on satellite, I don't tend to believe anything they say

