1 / 25

Flash Flood Prediction Working Group

Flash Flood Prediction Working Group. Q2 Workshop June 28-30, 2005. Mission of NWS Hydrologic Services Program. Provide river and flood forecasts and warnings for the protection of lives and property.

chesna
Télécharger la présentation

Flash Flood Prediction Working Group

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Flash Flood PredictionWorking Group Q2 Workshop June 28-30, 2005

  2. Mission of NWS Hydrologic Services Program • Provide river and flood forecasts and warnings for the protection of lives and property. • Provide basic hydrologic forecast information for the nation’s environmental and economic well being.

  3. Current Flash Flood Services • Primary WFO Products and Information • Flash Flood Watch • Flash Flood Warning BULLETIN - IMMEDIATE BROADCAST REQUESTED FLOOD WATCH NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA 930 AM PST WED FEB 18 2004 ...A FLASH FLOOD WATCH CONTINUES UNTIL 1100 PM FOR THE BURN AREAS OF VENTURA AND LOS ANGELES COUNTIES... A FLASH FLOOD WATCH MEANS THAT FLASH FLOODING IS POSSIBLE... BUT NOT IMMINENT...IN THE WATCH AREA. PEOPLE IN THESE AREAS SHOULD STAY ABREAST OF THE LATEST DEVELOPMENTS AND BE PREPARED TO TAKE IMMEDIATE ACTION IF A WARNING IS ISSUED OR FLOODING IS ENCOUNTERED. NATIONAL WEATHER SERVICE INSTRUCTION 10-922 WEATHER FORECAST OFFICE HYDROLOGIC PRODUCTS SPECIFICATION http://www.nws.noaa.gov/directives/010/010.htm

  4. Current Flash Flood Services • Product Dissemination • Internet (http://weather.gov/) • NOAA Weather Radio • Emergency Managers Weather Information Network • NOAA Weather Wire Service • Family of Services • NOAAPORT • EAS

  5. Verification • Flash Flood Warning verification statistics are based on product issuance information and confirmation of actual flash floods by the local WFOs. • Flash Flood Warning Lead Time • Flash Flood Warning Accuracy

  6. Impact of Technology, Training, Expanding Outreach and Dissemination on Flash Flood Services NEXRAD Implementation FFMP Implementation Where will the next improvement come from?

  7. Data and Decision Assistance Tools • Forecasters integrate observed and forecast information to assess the threat of flash flooding • Data sources include radar data and in-situ precipitation gages and FFG (e.g., ASOS and ALERT) • Decision assistance tools facilitate analysis of large and diverse data sets to identify conditions conducive to flash flooding

  8. Current Operational Practices for Predicting Flash Flood • FFMP • The Flash Flood Monitoring and Prediction (FFMP) Application is a new NWS radar-based Advanced Hydrologic Prediction Service (AHPS) decision assistance application • Site Specific • DamCREST • Traditional Methods

  9. FFMPAvailable Data and Algorithms

  10. Outstanding Science and Research to Operations Issues • Radar data availability is limited especially in the Western United States • WFOs served by more than one radar must run an instance of FFMP for each radar • Limitations of radar • Uses raw radar data precipitation estimates – no bias adjusting • Radar bins increase in size and altitude with distance from the radar • Brightband contamination • Hail contamination • Inaccurate Z/R relationships • Limitations of FFG • FFG is developed from hydrologic models calibrated for river forecasting of larger basins. The calibrations are not necessarily scalable for the basins associated with flash floods. • Discrepancies across RFC boundaries • Not appropriate for regions where the dominant flash flood factors are rainfall intensity and terrain

  11. Emerging Scientific Solutions for Predicting Flash Flood • Improved radar estimates of precipitation • Probabilistic QPE from Radar • Dual polarization radar precipitation estimates • Precipitation estimation from TDWR • Improved Multi-sensor Precipitation estimates • Improved Short Range QPF • FFMP improvements • Flash Flood Potential Index • Statistical Distributed Modeling • Distributed Modeling

  12. Emerging Scientific Solutions FFMP Improvements • Current research to operation efforts • Generate regionally-mosaicked, multi-sensor precipitation estimates every volume scan displayed on a 1 km grid for the time scales used in FFMP (0.5 hour, 1 hour, 2 hour and 3 hour) • Ingest gridded precipitation estimates (NMQ, MPE, Q2, QPF…) into FFMP • Toggle between multiple QPE inputs

  13. Emerging Scientific Solutions FFMP Improvements • Enhanced QPE/QPF Capabilities (NWS Operational Requirements Document - Flash Flood Monitoring and Prediction Fall 2003) • If scientific investigation shows that the increased spatial resolution is beneficial to precipitation estimates, then increase the spatial resolution of the multi-sensor precipitation estimates to 0.5 km by 0.5 km. • Increase frequency of integration of satellite QPE into multi-sensor precipitation estimates from every 60 minutes to every 15 minutes • Generate DHR-based rainfall products with a resolution of 0.5 by 0.25 km (ORDA FY08) • Provide capability to display and monitor QPF • Enhance the rain gauge network data flow from all sources and deliver to AWIPS for use in multi-sensor precipitation estimates and FFMP at 5 minute resolution. • Other requirements identified in the ORD include GIS improvements, improvements in FFMP Display methods, and improvements in FFG estimates

  14. Utilize GIS tools/methods to develop a single index that represents the a potential for flash flooding (on a relative scale) obtain raster (gridded) datasets representing the features of interest Emerging Scientific Solutions Flash Flood Potential Index

  15. Gridded –Relative– Flash Flood Potential Emerging Scientific Solutions Flash Flood Potential Index

  16. Summarize Grids to Geographic Layer (Basin) STATSGO Dominant Soil Texture FFMP Basins MLRC Land Use / Land Cover NOAA AVHRR Forest Density Grid USGS DEM (derived % slope Grid – Terrain) Fire Burn Areas / Severity coverage Relative Flash Flood Potential Low High An indication of rapid hydrologic response Emerging Scientific Solutions Flash Flood Potential Index

  17. Emerging Scientific Solutions Flash Flood Potential Index • Currently researching methods to add a soil moisture layer to FFPI to support national implementation. • Will need to integrate gridded 1-hour multi-sensor precipitation estimates to estimate soil moisture.

  18. Methodology 1. Using observed data for a region, derive a probability distribution describing the chance of exceeding a flood threshold given a computed flow frequency Regional flood threshold estimate (2) (3) Forecasted peak flow 2. Derive a simulated climatology for each model grid cell 3. Given a forecasted flow, derive the probability of exceeding simulated climatology for each model grid cell (1) 0.82 0.63 Shaded area is probability of exceeding bankfull flow. Observed Simulated Emerging Scientific Solutions Statistical Distributed Model

  19. Emerging Scientific Solutions Statistical Distributed Model • Precipitation Estimation requirements • Initial Proof of Concept with Hourly Stage III products on an HRAP grid. • Model framework can be used to test precipitation estimates at higher spatial and temporal resolutions • Plan to expand approach to ingest 1-hour forecast precipitation grids.

  20. Arkansas R. Red R. Blue R. Emerging Scientific Solutions Distributed ModelingDistributed Model Intercomparison Project

  21. 200 160 Flow (CMS) 120 80 40 0 4/3/99 0:00 4/3/99 12:00 4/4/99 0:00 4/4/99 12:00 4/5/99 0:00 4/5/99 12:00 4/6/99 0:00 Hydrograph at Location A 200 Distributed Lumped Observed 160 A Flow (CMS) 120 80 40 B 0 4/3/99 0:00 4/3/99 12:00 4/4/99 0:00 4/4/99 12:00 4/5/99 0:00 4/5/99 12:00 4/6/99 0:00 Hydrograph at Location B 200 160 Flow (CMS) 120 80 40 0 4/3/99 0:00 4/3/99 12:00 4/4/99 0:00 4/4/99 12:00 4/5/99 0:00 4/5/99 12:00 4/6/99 0:00 Hydrographs at Basin Outlet Emerging Scientific Solutions Distributed Modeling Hydrologic Response at Different Points in the Blue River Basin

  22. Emerging Scientific SolutionsDistributed Modeling Application of HL Distributed Model

  23. Emerging Scientific Solutions Distributed Modeling • Precipitation Estimation requirements • Hourly Stage III products on an HRAP grid.

  24. Precipitation Requirements for Flash Flood Prediction • Improved quality of precipitation estimates • Accurate high–resolution seamless multi-sensor gridded precipitation estimates • Timely estimates every five minutes as close to real-time (minimize processing, latency, … without degrading quality) • Ingest short-term (0-1 hour) high quality seamless QPF • Carry forward human quality control knowledge interaction to real-time QPE estimates • Improve gauge quality and network • Gap filling mechanisms • Satellite estimates • Hourly updates for soil moisture components

  25. Other Priorities for Flash Flood Prediction • Improved FFG • Societal Impacts and Public Perception • Verification • Ground Truth • Flash Flood Climatology • Training • GIS Solutions - Fire scars • Uncertainty • Visualization

More Related