Item SR-15: 2011 Project Update on Expressions of Uncertainty Initiative

Highlights New Probability thresholds introduced in For the most part seemed to work well except for thresholds appearing to be too high on the periphery of the systems (show slides if possible with South Florida and Emily examples). New Probability thresholds introduced in For the most part seemed to work well except for thresholds appearing to be too high on the periphery of the systems (show slides if possible with South Florida and Emily examples). ER formatter team implemented GUI option to change analyzed probability to be compare against threshold. Default: Max Probability; Options based on ModeratedMax(#) designed to change sensitivity of the formatters to the probabilities. Guidance provided to implement this include: ER formatter team implemented GUI option to change analyzed probability to be compare against threshold. Default: Max Probability; Options based on ModeratedMax(#) designed to change sensitivity of the formatters to the probabilities. Guidance provided to implement this include: – Forecast from successive adv trends towards west of 75W while south of 35N with movement that is WNW to North - stick to Max. – If track does not meet condition but forecast trends keep it W of 70W with a NW motion passed 35N stick to Max. – Otherwise use alternate ModeratedMax(#) probabilities.

Highlights No new major issues during No new major issues during Irene: issue with forecast databases not being updated on time resulting in point and click out of sync with forecast track. Irene: issue with forecast databases not being updated on time resulting in point and click out of sync with forecast track. Issued found in ER during 2010 with Wx phrases dropping from CWF Extended periods addressed. Issued found in ER during 2010 with Wx phrases dropping from CWF Extended periods addressed. Single most important finding this season: 20 knots wind speeds required in the extended periods to trigger EoU even when probability threshold is exceeded. Accentuated by increase in thresholds. Single most important finding this season: 20 knots wind speeds required in the extended periods to trigger EoU even when probability threshold is exceeded. Accentuated by increase in thresholds. ER brought up issues with the icons in point and click being entirely taken over by the tropical icon when EoU is generated. Dave Sharp proposed to consider changing the location of the EoU in the text depending whether conditions are possible or expected. ER brought up issues with the icons in point and click being entirely taken over by the tropical icon when EoU is generated. Dave Sharp proposed to consider changing the location of the EoU in the text depending whether conditions are possible or expected. Important issue lingering from 2010 season: in the short range if EoU is triggered because of probability threshold exceeded but wind speed is less than 15 to 20 knots should we create exception to drop the deterministic phrase in those cases? Counter point: customer still needs/wants that info. In Favor: such low wind speed values might negate the precautionary response that is sought after. Important issue lingering from 2010 season: in the short range if EoU is triggered because of probability threshold exceeded but wind speed is less than 15 to 20 knots should we create exception to drop the deterministic phrase in those cases? Counter point: customer still needs/wants that info. In Favor: such low wind speed values might negate the precautionary response that is sought after. If Official things to formalize: Tropical SAF issues - Are offices taking the time to set this up? If Official things to formalize: Tropical SAF issues - Are offices taking the time to set this up? If Official things to formalize: Back Up Capabilities - Training Back up sites. If Official things to formalize: Back Up Capabilities - Training Back up sites. If Official things to formalize: Public and Marine directives will need to be updated. If Official things to formalize: Public and Marine directives will need to be updated. RECOMMENDATION: To make decisions addressing issues above. Official or Not yet. Issues potentially to come up with Irene Service Assessment might argue in favor of holding off. RECOMMENDATION: To make decisions addressing issues above. Official or Not yet. Issues potentially to come up with Irene Service Assessment might argue in favor of holding off.

4 PhrasePeriodPWS64PWS34 POSSIBLE00-12 hr40%50% hr32.5%45% hr25%40% hr20%35% hr15%30% hr12.5%25% hr10%22.5% hr8%20% hr6%17.5% hr5%15% (Periods 1-10: When conditions are POSSIBLE) Triggers

5 PhrasePeriodPWS64PWS34 POSSIBLE00-12 hr30%55% hr25%45% hr20%40% hr15%35% hr10%30% hr7%25% hr6%20% hr5%15% hr4%12.5% hr3%10% (Periods 1-10: When conditions are POSSIBLE) Triggers – 2010 and before