Flash Flood Monitoring and Prediction Current Operational Capabilities, Issues and Perspectives Britt Westergard, Service Hydrologist WFO Jackson, KY Q2 Workshop – June 28, 2005

Slide courtesy of Mary Mullusky Data and Decision Assistance Tools Forecasters integrate observed and forecast information to assess the flash flood threat Data sources include radar data and in-situ precipitation gages (e.g., ASOS and ALERT) Decision assistance tools facilitate analysis of large and diverse data sets to identify conditions conducive to flash flooding The Flash Flood Monitoring and Prediction (FFMP) Application is a new NWS radar- based Advanced Hydrologic Prediction Service (AHPS) decision assistance application

Slide courtesy of Mary Mullusky FFMP Continuous monitoring of rainfall rate and accumulation with comparison to flash flood guidance for high resolution stream basins Automated alerts when a dangerous flash flood situation may be developing on a given stream or catchment Released to WFOs in AWIPS in 2002

Slide courtesy of Mary Mullusky FFMP Available Data and Algorithms

Slide courtesy of Mary Mullusky FFMP: Forecaster Interface County Precipitation Accumulation Displays precipitation for the basin in the county that has highest accumulation FFMP 1.0 Hour Basin Avg Precip

Slide courtesy of Mary Mullusky FFMP: Forecaster Interface Basin Precipitation Accumulation Displays basin precipitation within the selected county FFMP 1.0 Hour Basin Avg Precip

Current Operational Capabilities Brand New Functionality Monitor Small Streams on Large Scale

Current Operational Capabilities Brand New Functionality Monitor Basins of Various Sizes on a Large Scale Image courtesy of WFO Springfield, MO

Current Operational Capabilities The Field Perspective “The best flash flood tool that has ever been implemented.” Streamlink files (pseudo-streams) to visualize water routing Forced Flash Flood Guidance Provide basin names in Flash Flood Warnings and Statements – customers more likely to take action

Current Operational Issues Three components to FFMP: Quantitative Precipitation Estimate (QPE) Flash Flood Guidance (FFG) Quantitative Precipitation Forecast (QPF)

Current Operational Issues – QPE – Current operational methods for compensating for radar QPE inaccuracies –Basin trends chart with gage data –Incorporate MPE bias into radar precipitation processing –“Ratio of the day” approach No radar, no FFMP – investigate additional QPE sources (satellite?)

Current Operational Capabilities The Field Perspective Basin Trend Graph

Current Operational Issues – FFG – Local research into baseline FFG versus precipitation (ratio) – thresholds for issuing particular products (USS vs FFW) Improved FFG from RFCs – local coordination essential Other guidance solutions beyond FFG…?

Current Operational Issues – Current QPF – Current focus is on Flash Flood Monitoring Very short term QPF (1/3/6 hours) is essential to the Prediction in FFMP Short-term QPF currently available in FFMP is SCAN 1-hour QPF – not widely used, documentation issues Also more generalized QPF available (RFC 6 hour QPF – not ideal resolution for flash flood prediction)

Current Operational Issues – Future QPF – Improved or additional sources of very short term QPF needed Software ideally would add QPF and QPE to give a predicted ratio – significant lead time increases Forecaster knowledge of algorithms used is important for confidence in QPF

Current Operational Issues – The Hydrology Side – Ability to track or route water (FFMP may not be the venue for this) Basin customization – local knowledge increases utility of software Improved maps of different basin aggregation levels to assist in watershed visualization

So, what’s your point? The field’s need for improved QPE and very short term QPF is apparent. The platform to implement these improvements in a way useful to the WFOs already exists – FFMP!