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It’s always sunny and 72 in San Diego, right?

It’s always sunny and 72 in San Diego, right?. Jim Purpura Meteorologist-In-Charge WFO SGX. Long lived (5+ hours) supercell began in Mexican coastal waters Produced at least two tornadoes This is not a waterspout (note RFD notch) but a supercellular tornado over the Pacific.

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It’s always sunny and 72 in San Diego, right?

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  1. It’s always sunny and 72 in San Diego, right? Jim Purpura Meteorologist-In-Charge WFO SGX NWS San Diego

  2. Long lived (5+ hours) supercell began in Mexican coastal waters Produced at least two tornadoes This is not a waterspout (note RFD notch) but a supercellular tornado over the Pacific February 19, 2005 © Dave Chapman Tornado off Huntington Beach 2/19/05 7:38 a.m. WFO San Diego

  3. FEBRUARY 19, 2005STORM DATA WFO San Diego

  4. So…how did we do? • Not very well! • Situational Awareness Poor • Staff not aware of 4:53 am PST MCD discussing tornado potential • Skywarn not activated, no spotters out • Staff used Composite Reflectivity, not 4 panel • Often used in complex terrain due to blockage factors • Severe Thunderstorm Warning Issued, then changed to Tornado Warning • Based on MIC’s view of radar at home and visual spotting of wall cloud and developing RFD WFO San Diego

  5. MCD issued at 4:53 am had it right… WFO San Diego

  6. KNKX OBSERVED SOUNDING, 1200Z 02/19/2005 WFO San Diego

  7. KNKX 4-PANEL SRM2-19-2005 17:20 GMT WFO San Diego

  8. KNKX 4-PANEL REF2-19-2005 17:20 GMT WFO San Diego

  9. Supercell was on radar for 5 ½ hours! (1245Z-1820Z) WFO San Diego

  10. Why is this important? Tornadoes rarely occur in southern California, right? WFO San Diego

  11. “Tornado frequency per unit area per time in the Los Angeles Basin is higher than the state of Oklahoma.” • A quote from Jack Hales (presentation to SGX staff 12/05) His data… • In the Los Angeles Basin, for the period of 1950-1992, there were 3.19x10-4 tornadoes km-2yr-1. • In the state of Oklahoma, there were 2.86x10-4 tornadoes km-2yr-1 for the same period. • A high end EF-2 or low end EF-3 is probably the maximum possible, based on records WFO San Diego

  12. Population in southern California is Huge • LOX CWA ~ 12,000,000 population • SGX CWA ~ 10,000,000 population • Together this merging metro area has ~ 7% of the population of the US • Benign weather mentality makes preparation for low probability, high impact events extremely difficult WFO San Diego

  13. So…what have we done to avoid this next time? • This was made into a WES case • Required for all ops staff. • MCD product set to alarm when “SGX” mentioned in text string. • We brought Jack Hales to the office to talk about southern California tornadoes. • Jack was uniquely familiar with local challenges. • Jack lived in southern California. • Worked to decrease dependence on algorithms and Composite Reflectivity vs. base data. • Still a struggle. In most situations Composite Reflectivity works well. Forecasters gravitate to it. WFO San Diego

  14. Some thoughts… • After years of working with the staff on these extremely rare events, it’s probably not possible to get them all to a “Plains level” of Situational Awareness for Severe Weather. • We do have a cadre of 6 good severe weather (warning) forecasters. • We try to anticipate an event and make sure one of the cadre is available. WFO San Diego

  15. We need a bit more help from SPC than Midwest or Plains offices in recognizing these events Random probably of an event is low but large population may potentially be at risk. Rare nature of events mean few forecasters will be true severe weather “experts” Pattern recognition is getting better, but still needs to improve. SPC – please call us if we don’t seem to “get it”! Final Thoughts… WFO San Diego

  16. Questions? • Thanks to Jack Hales for some of the slides from his 12/05 presentation at SGX • Tornado picture from Dave Chapman at www.stormdude.com WFO San Diego

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