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- ZOA CWSU SFO Approach Cumulus Study
- Models have difficulty resolving coverage, development, and movement of terrain-influenced cumulus over SFO approach
- Models tend to overestimate coverage of post-frontal and other cumulus over SFO approach
- Can cause several hours of reduced arrival rate at SFO even with scattered clouds over approach
- Combination of certain parameters likely determine whether SFO will be impacted by cumulus
- Hypothesis is that strong westerly winds enhance chances for terrain-induced cumulus to impact SFO approach
- Looked at:
- Days where cumulus with scattered or greater coverage formed over bay area
- 12Z OAK temperature profile
- 12Z OAK wind profile
- Model data
- Initial findings for 08-09
- 100% chance for cumulus to impact approach when each of these conditions exists:
- 12Z wind direction 220-320 at 1000MB and 925MB
- 12Z wind speed > 20KT at 925MB
- 12Z 1000MB and 925MB relative humidity > 75%
- Status
- Classify events as frontal and non-frontal cumulus days
- Explore other possible correlations
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