The Lake Pontchartrain Forecast System Rick Luettich Jason G. Fleming Institute of Marine Sciences University of North Carolina

The Team University of North Carolina: Rick Luettich, Jason Fleming, Crystal Fulcher University of North Carolina: Rick Luettich, Jason Fleming, Crystal Fulcher Louisiana State University: Robert Twilley, Gabrielle Allen, Ed Seidel, Brett Estrade Louisiana State University: Robert Twilley, Gabrielle Allen, Ed Seidel, Brett Estrade University of Notre Dame: Joannes Westerink University of Notre Dame: Joannes Westerink US Army Corps of Engineers: Harley Winer US Army Corps of Engineers: Harley Winer

Interim Gated Structures

Mission Statement

Provide real-time support for closure decisions for Orleans Parish outfall canals Provide real-time support for closure decisions for Orleans Parish outfall canals –Predict stages in Lake Pontchartrain at the mouths of the outfall canals –Predict wind speeds near the mouths of the canals –USACE and LSU provide computing resources

The Scope of Work Calculate storm surge and wind speed using ADCIRC Calculate storm surge and wind speed using ADCIRC 4 Day forecast completed in within 2 hours 4 Day forecast completed in within 2 hours –Accurate wind conditions and storm surge from a tropical cyclone –Ensemble of alternate cyclones that reflect a reasonable range of possible conditions

LPFS in a Nutshell Rely on text advisories from NOAA NHC Rely on text advisories from NOAA NHC Automated software system to Automated software system to –Download advisories –Configure ADCIRC runs –Compute wind fields on the fly –Assemble output from ADCIRC and plot results at locations of interest – graphs to decision makers and copy to redundant external websites

Phase I Create mesh with 100k nodes Create mesh with 100k nodes Implement dynamic Holland wind model Implement dynamic Holland wind model Verify that we get within 10% of IPET for Katrina Verify that we get within 10% of IPET for Katrina Define ensemble of 5 members Define ensemble of 5 members Plot wind speed and water level at station locations Plot wind speed and water level at station locations

The Grid

Holland Wind Model Analytical Description Analytical Description Input data: Input data: –Central pressure deficit –Maximum wind speed –Radius to maximum winds

Ensemble Members 1. NHC Consensus storm, 5 day forecast 1. NHC Consensus storm, 5 day forecast 2. Storm with 20% higher wind speed 2. Storm with 20% higher wind speed 3. Storm with 20% slower forward speed 3. Storm with 20% slower forward speed 4. Storm that veers along right of cone of uncertainty 4. Storm that veers along right of cone of uncertainty 5. Storm that veers along left of cone of uncertainty 5. Storm that veers along left of cone of uncertainty

Veer Right and Veer Left

Examples of Early Warning Katrina: veer left storm Katrina: veer left storm Rita: veer right storm Rita: veer right storm Ernesto: threat yet or not? Ernesto: threat yet or not?

Katrina

Early Warning – Veer Left

Rita

Early Warning – Veer Right

Rita Early Warning

Ernesto

Ernesto – Nearest Forecast

Phase II Modify Phase I to use hotstarting Modify Phase I to use hotstarting –Completed during hurricane season 2006 Initiate daily runs forced by tides Initiate daily runs forced by tides –Tides are relatively small –Strategy change to increase speed Add any other meteorological products Add any other meteorological products –Timeliness is main issue –Ongoing search for speed and accuracy

Coldstart system

Hotstart System

Lessons Learned Performance Performance –Multi-machine development at LSU –Added hotstart capability –Generalized system for portability Turnaround times Turnaround times –LSU: 1—7 hours initially –USACE: minutes with real time queue

Lessons Learned Resources Resources –Priority access not guaranteed except at USACE –Optimization needed for LSU hardware –LSU and USACE machines operate redundantly Communications Communications –Mirrored results at several redundant websites, including LSU and UNC –Enhanced notification s to include attachments containing graphs of results

Hurricane Season 2007 System oversight System oversight Systematically assess wave setup Systematically assess wave setup –Compute proportionate effect in historical storms –Use synthetic pack of storms to calculate a multiplier or; –Integrate STWAVE into LPFS Modify storm ensemble Modify storm ensemble

Hurricane Season 2007 Hotstart with tides Hotstart with tides Hotstart with background meteorology Hotstart with background meteorology Inclusion of land use characteristics Inclusion of land use characteristics Enhanced user interface Enhanced user interface Enhanced output Enhanced output –Maximum Envelope Of Water (MEOW) –Maximum of Maximums (MOM) across ensemble –Maximum Envelope of Wind