# Presentation: 850088

## Improving Flash Flood Services

**Improving Flash Flood Services**

- Mary Mullusky
- National RFC Hydrologic Services Program Leader
- Hydrologic Services Division
- Office of Climate, Water and Weather Services

*National Hydrologic Program Managers Conference*
*July 10, 2007*

## Outline

**AHPS Flash Flood Services Theme Team**
**Flash Flood Services Projects**
**QPE/QPF Improvements **
**FFG Improvements**
**FFMP Improvements**
**Site Specific Hydrologic Predictor Improvements**
**Dam Break Tools **

- Improving Flash Flood Services

## Outline

- Improving Flash Flood Services
- AHPS Flash Flood Services Theme Team

**Team Members**
- Mary Mullusky* (NWSH/HSD)
- Bill Lawrence (ABRFC)
- Peter Ahnert (MARFC)
- Greg Smith (CBRFC)
- Brian McInereny (WFO – Salt Lake City)
- John Woynick (WFO – Topeka)
- Frank Bell (WGRFC)
- George McKillop (ERH/HSD)
- 		* Ernie Wells will be FY2008 team leader

**Technical Representatives**
- David Kitzmiller (NWSH/OHD)
- Seann Reed (NWSH/OHD)
- Ed Danaher (NCEP/HPC)
- Mark Glaudemans (NWSH/OHD)
- Mark Fresch (NWS/OHD)
- Reggina Cabrera (NWS/OHD)
- Tom Donaldson* (NWSH/HSD)
- Tom Filiaggi (NWSH/MDL)
- Ken Howard (NSSL)

**FY07 Team Process **
- Team evaluated over 20 AHPS flash flood projects
- Team prioritized projects and created funding proposals
- Team leader presented proposals to the AHPS Program Coordinator and the AHPS Review Committee
- Hydrology Program Manager has final authority

## Outline

- Improving Flash Flood Services
- QPE/QPF Improvements

- increased reflectivity data resolution from 1 km to 1⁄4 km;
- increase azimuthal resolution of reflectivity, velocity and spectrum width from 1° to 0.5°;
- extend the range of Doppler data from 230 km to 300 km
- Derived products will not use super resolution in this build
- Nexrad Product Improvement recently tasked OHD to compare derived precipitation products from super resolution and standard resolution

**Super Resolution (Build 10, AWIPS OB 8.2)**

## Outline

- Improving Flash Flood Services
- QPE/QPF Improvements

- Improved precipitation estimation, Improved data quality, improved hail identification, and hydrometeor classification
- 1 degree by 1⁄4 km data for base products and most derived products
- DHR will still exist (for now)
- DPR (Digital Precipitation Rate) is the dual polarization replacement product for DHR
- FFMP – Advanced Design (AWIPS OB 8.3) should be able to ingest DPR for monitoring and display

**Dual Polarization (Build 11, AWIPS OB8.3 + 2 year deployment)**

## Outline

- Improving Flash Flood Services
- QPE/QPF Improvements

- High resolution rain rate and precipitation accumulation grids
- spatial resolution 1/4 HRAP mesh length  (~1x1 km)
- Update frequency configurable up to 5 minute intervals
- DHR used to create radar rain rate estimates
- Gages are **NOT** used in this version of EMPE, however the MPE gage-radar bias table can be used in rain rate and accumulation estimation
- Dual Polarization DPR **NOT** used in this version of EMPE

**Enhanced Multisensor Precipitation Estimation (EMPE) (AWIPS OB8.3)**

## Outline

**Multisensor Precipitation Nowcaster (MPN) (AWIPS OB9.0)**
- An extrapolative forecast of the reflectivity field valid for the next hour, updated every 15 minutes on an HRAP grid. Additional fields for AWIPS display include:
- 1-hour radar precipitation accumulation forecast (with and without bias correction)
- Instantaneous rain rate forecasts at 15 minute intervals out through 1-hour (with and without bias correction)
**RFC MPE Mean Field Bias to WFO (AWIPS OB8.2)**
- WFO operators can select which RFC bias message to receive and which bias message to send to the RPG
**NMQ/Q2 infusion into NCEP (no targeted build)**
**Probabilistic QPE (no targeted build)**

- Improving Flash Flood Services
- QPE/QPF Improvements

## Outline

- Improving Flash Flood Services
- FFG Improvements

**ABRFC’s Gridded FFG**

- Produce a flash flood guidance product at a resolution similar in scale to FFMP
- Gridded FFG is derived from HRAP resolution (~4km x4km) of**:**
- Soil moisture conditions from the Hydrology Lab - Research Distributed Hydrologic Model
- Dynamic NRCS Curve Number from soil data and land use land cover data and distributed model soil moisture conditions
- NRCS Unit Hydrograph model combined with a design storm to estimate bankfull flow (Thresh-R)
- Method treats each HRAP grid cell as an independent headwater basin

**Gridded FFG**

- For more details see the Gridded Flash Flood Guidance topical breakout session

**OHD RDMS Soil Moisture**

**Dynamic NRCS Curve Number**

**Variable**
**Threshold Runoff**

- Slope

- Length to divide

- Static CN

- Area

- Duration

- 2-yr, 3-hr DDF

**Gridded Runoff**

## Outline

- Improving Flash Flood Services
- FFG Improvements

**ABRFC’s Gridded FFG**

**Status:** Developing 1, 3, and 6 hour FFG and Thresh-R

- Fully
- Operational
- Under
- Development
- To be
- developed
- In FY07

## Outline

- Improving Flash Flood Services
- FFG Improvements

**Vegetation type and density**** **

**Soil type**

**Land Use **

**Wildfire**

**Slopes**

- Using GIS and digital data of soil type, vegetation type and density, slope, and land use create a single value index of hydrologic response.
- Developed a process to modify FFPI with wildfire burn severity information.

**CBRFC’s Flash Flood Potential Index**

## Outline

- Improving Flash Flood Services
- FFG Improvements

**Current Status**
**Prototypes Completed: **
**To be completed in FY07: **
**Future development**
**Incorporate dynamic soil moisture component **
**Derive FFG from relationships between the FFPI and historical event data.**

**CBRFC’s Flash Flood Potential Index**

## Outline

- Improving Flash Flood Services
- FFG Improvements

- Forecast
- frequencies

- Historical

- Real-time

- Initial hydro model states

- Statistical
- Post-processor

- Distributed hydrologic model

- Distributed hydrologic model

- Max forecast
- peaks

**Compare**

- Flow (cms)

- Probability

**Distributed Hydrologic Model – Threshold Frequency Methodology**

- Frequency
- thresholds

- Local/regional knowledge

- Simulated peaks distribution (Qsp) (unique for each cell)

- Run distributed hydrologic model in ‘historical’ mode to create a simulated peaks distribution for each grid cell
- Run the distributed hydrologic model in real-time to create a maximum forecast peak for each grid cell
- Use a statistical post-processor to create forecast frequencies for each grid cell from the maximum forecast peak and the simulated peaks distribution
- Compare forecast frequencies with frequency threshold from local/regional knowledge

## Outline

- Improving Flash Flood Services
- FFG Improvements

**Distributed Hydrologic Model – Threshold Frequency Method**

**Benefits**
- Relative measure (easier to understand than CMS)
- Inherent bias correction
- Local information often available to help define thresholds (e.g. engineering design, geomorphology studies)
- Can be used when ‘bankfull’ flow is not meaningful (e.g. slot canyons)
**Limitation**
- Required data may not be available everywhere
**Current Status**
- Developing prototype for flash flood prone Baltimore area

## Outline

- Improving Flash Flood Services
- Summary of FFG Improvements

## Outline

- Improving Flash Flood Services
- FFMP Improvements – AWIPS OB7.2

**X**

**Emphasized Forced Flash Flood Guidance**

**Virtual Gage Basins**

**Zoom X**

## Outline

- Improving Flash Flood Services
- FFMP Improvements – AWIPS OB7.2

**Basin Trace Fix – consistent hatching**

## Outline

- Improving Flash Flood Services
- FFMP Improvements – AWIPS OB8.1

**Basin Trace Fix – editable**

## Outline

- Improving Flash Flood Services
- FFMP Improvements AWIPS OB8.3

## Outline

- Improving Flash Flood Services
- FFMP Improvements AWIPS OB8.3

- Precipitation Sources
- DHR
- DPR
- EMPE
- NMQ (in prototype)
- SCAN QPF
- MPN (w/ OB9.0)

- Join duration from different sources
- For example a 3 hour duration derived from 1 hour MPN and 2 hours EMPE

- FFG Sources
- Legacy FFG
- Gridded FFG
- Debris Flow Guidance

## Outline

- Improving Flash Flood Services
- WarnGen

- FFMP Basin names in WarnGen

- OB 8.2 ?

## Outline

- Improving Flash Flood Services
- Site Specific Hydrologic Predictor Improvements – OB8.2

**Precip visualization and save/reload**

**Select alternate UHG (if defined)**

**Action, minor, moderate, and major **
**stages displayed (if defined)**

## Outline

- Future development (targeted for OB9 – Gulf offices may see earlier)
- Simplified Routing: Variable Lag and Variable K routing
- A separate variational data assimilation program to update the states of the SSHP SAC-SMA rainfall runoff model

- Improving Flash Flood Services
- Site Specific Hydrologic Predictor Improvements

## Outline

- Improving Flash Flood Services
- Dam Break Tools

**Goal:** Review the database and existing tools for simplified dam break
**Status: **Project delayed due to staff shortages in the Hydraulics Group of OHD

## Improving Flash Flood Services

**Improving Flash Flood Services**

- Thank you!
- Any Questions?

*National Hydrologic Program Managers Conference*
*July 10, 2007*