PRIMUSr 880 Digital Weather Radar System
Although penetrating a storm with a red (level three) core appears to be an acceptable risk, it is not. At the lower end of the red zone, there is no chance of extreme turbulence, a slight chance of severe turbulence, and a 40% chance of moderate turbulence. However, the radar lumps all of the rainfall rates between 12 mm to 50 mm per hour into one group
-a level three (red). Once the rainfall rate reaches the red threshold, it masks any additional information about the rainfall rate until the magenta threshold is reached. A red return covers a range of turbulence probabilities and the worst case must be assumed, especially since extreme, destructive turbulence is born in the red zone. Therefore, once the red threshold is reached, the risk in penetration becomes totally unacceptable.
Likewise, once the magenta threshold is reached, it must be assumed that more severe weather is being masked.
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| LEVEL 1 | LEVEL 2 | LEVEL 3 | LEVEL 4 | |
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| GREEN | YELLOW | RED | MAGENTA | |
| 100% | LIGHT |
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| 90% |
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PROBABILITY | 80% |
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70% |
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60% |
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TURBULENCE | 50% |
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40% |
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30% |
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20% |
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| 10% |
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| 0% |
| (4 mm / Hr) | (12 mm / Hr) | (50 mm / Hr) | |
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| RAINFALL RATE | AD- 15357- R2@ | ||
Probability of Turbulence Presence
in a Weather Target
Figure 5- 29
A28- 1146- 102- 00 | Radar Facts |
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