Part2 WhenBadThingsHappent oGoodForecasters

When Bad Things Happen to Good Forecasters…Part II : When Bad Things Happen to Good Forecasters…Part II David Andra WFO Norman, Oklahoma


Or…Why those who forget history… are condemned to repeat it !! : Or… Why those who forget history… are condemned to repeat it !!


Why do we make wrong decisions? : Why do we make wrong decisions? Fatigue Distraction Faulty Conceptual Model Overconfidence Missing Key Information Over Projection of Trends


When Bad Things Happen… : When Bad Things Happen… Nobody is immune !!


A Couple of Case Studies… : A Couple of Case Studies… WFO Norman Spring 2002 Why did bad things happen?


You Make the Call : You Make the Call Contributing Factors? Lessens Learned?


Case Number 1 : Case Number 1 Unwarned F3 tornado No injuries April Near Midnight Northwest Oklahoma


Case Number 1 : Case Number 1 Supercells develop by 21Z Tornado watch 2 warning sectors Through 03Z Baseball hail Few brief, weak tornadoes


Case Number 1 : Case Number 1 After 04Z “Mop Up” Severe T-storm Watch 1 Warning Sector Previous 2 Warning Forecasters went home SOO stayed to monitor until evening shift could take over.


What factors should we be wary of at this point ? : What factors should we be wary of at this point ?


Timeline to trouble, and success : Timeline to trouble, and success 0417(Z) SVR issued 0423 SVS issued – Tennis ball hail psbl 0427 SVR extended downstream (inter office and SPC Coord) 0440 Concern over meso signature, no ground truth, want persistence based on past history of storms that evening.


Timeline to trouble, and success : Timeline to trouble, and success Tornado 0435-47 4.5 mile path Perhaps F3 No injuries Damage mostly to trees, power lines, and abandoned old house


Timeline to trouble, and success : Timeline to trouble, and success Signature steady and strengthening (actual tornado not reported until next day) 0453 TOR issued based on radar SHIFT CHANGE 0503 SVS for strong circulation 0522 SVS for spotter tornado and TVS 0526 TOR extended downstream


Timeline to trouble, and success : Timeline to trouble, and success Long track tornado Approx 0522-0628 34 mile long track, 1 mile wide Rated F2 Glancing blow unroofed on home, severe tree damage


Timeline to trouble, and success : Timeline to trouble, and success Between 0530 and 0655 10 SVS – Large tornado, extremely dangerous and life threatening, pathcast 3 TOR 1 additional tornado (F0)


Long track tornado well handled, : Long track tornado well handled, But… Significant F3 unwarned! WHY?


Why did we make wrong decisions? : Why did we make wrong decisions? Fatigue Distraction Faulty Conceptual Model Overconfidence Missing Key Information Over Projection of Trends


Why did we make wrong decisions? : Why did we make wrong decisions? Fatigue…SOO around since 8 AM Distraction…shift change, coordination Faulty Conceptual Model…environment thought to favor SVR Overconfidence…thought we knew what was going on Missing Key Information…spotters Over Projection of Trends…past trends weighed too heavy


Case Number 2 : Case Number 2 Damaging Wind Event No injuries May Late Evening Central & Western Oklahoma


Case Number 2 : Case Number 2 Isolated storms develop through 03Z No watch 1 warning sector at times Through 0300Z Isolated marginal svr Supercells in CWA to west


Case Number 2 : Case Number 2 After 0300Z Rapid Storm Development Tornado Watch 2 Warning Sectors Regular staff assumes warning responsibility (2 forecasters, 1 HMT)


What factors should we be wary of at this point ? : What factors should we be wary of at this point ?


Timeline to trouble, and success : Timeline to trouble, and success 0251(Z) first SVR issued 0255 two county SVR 0317 SVR issued 0327 TOR issued 0342 SVR issued 0342 SVR issued (not duplicate) 0347 two county SVR


Timeline to trouble, and success : Timeline to trouble, and success 0423 FFW issued 0427 three county SVR 0429 SVR issued 0436 two county TOR issued 0438 SVR issued Additional (extra) Staff Arrive Four more counties receive SVR before mid shift arrives at 0500


Timeline to trouble, and success : Timeline to trouble, and success Major damaging wind event north west Oklahoma (80+ mph) No NOW Few SVS Tornadoes? No amateur radio coverage until 0415 TV stations speculated on wall to wall coverage


Slide27 : WIND? TORNADO?


Some Confusion.. : Some Confusion.. Severe Thunderstorm Warning 1127 PM CDT “…These thunderstorms are capable of producing particularly damaging winds…hail to 2 inches…”


Some Confusion.. : Some Confusion.. Tornado Warning 1136 PM CDT Basis…“…Severe thunderstorm capable of producing a tornado…” CTA… “…extremely dangerous and life threatening… …If you are in the path of this large and destructive tornado…”


Slide30 : First…TOR Then…SVR


No known missed events : No known missed events But… some confusion in the message and at times lack of message WHY?


Why did we make wrong decisions? : Why did we make wrong decisions? Fatigue Distraction Faulty Conceptual Model Overconfidence Missing Key Information Over Projection of Trends


Why did we make wrong decisions? : Why did we make wrong decisions? Fatigue…probably not Distraction…perhaps (equipment O.K.) Faulty Conceptual Model…sometimes Overconfidence…yes, busier than expected Missing Key Information …spotter reports, amateur radio Over Projection of Trends…likely to some extent


Recommendations : Recommendations Post mortems Be prepared to be sensitive and constructive Depersonalize the event Analyze where process failed (Root Cause Analysis) Look for trends Make staff aware Plan to change


Questions ?? : Questions ??