Innovations in Flood Forecasting at the National Weather Service West Gulf River Forecast Center Kris Lander, PE, CFM Gregory Waller NWS West Gulf River Forecast Center NWS Mission To provide weather, water, and climate data, forecasts and warnings for the protection of life and property and enhancement of the national economy. NWS accomplishes this mission in close collaboration and cooperation with State, Local, and Other Federal Agencies The WGRFC Area Diverse Water Issues Snowpack Water supply 402,000 mi 2 total area 87,000 mi 2 in MX (Rio Grande headwaters) 320 forecast points, 15 major river systems Over 65,336 miles of rivers (U.S. only) Hill Country Hydrology Flash flood threats Rapid river responses Cycles of Flood/Drought 1
COMMUNITY HYDROLOGIC PREDICTION SYSTEM (CHPS) The CHPS Forecast System Community Hydrologic Prediction System Hydrologic Model Think more math, less physics Has capability of plugging in other models Forecasters check out and check in model runs CHPS Forecaster Desktop CHPS Hydrograph Plots 2
CHPS Forecaster Desktop Spatial Data Viewer and Modifiers RDHM SacHT Output SAC-SMA Soil Accounting Model Output 5cm 10cm 20cm 50cm 100cm Fractional Water Content at Depth Forecaster Expertise and Modifiers This UHG is for Sandy Creek near Cordele, part of the Lavaca/Navidad River system 3
The Result Our Model Higher Resolution Modeling Guadalupe/Blanco Higher Resolution Modeling Guadalupe/Blanco 2 Wimberly Basins Upper and Lower 1 Forecast Point 7 Basins Crabapple, Blanco, Little Blanco, Fischer Store Rd Upper and Lower, Jacob Springs, Wimberly 5 Forecast Points 4
Total Water New Model Efforts Upstream HECRAS Boundary Downstream Boundary FLOOD INUNDATION MAPPING: FEMA DFIRMS & AHPS FIM FEMA DFIRM on NWS AHPS 5
AHPS Flood Inundation Mapping AHPS Flood Inundation Mapping Locations 25 States 32 River Forecast Points - Texas 154 River Forecast Points - Nationwide http://water.weather.gov/ahps/inundation.php PROBABILISTIC QUANTITATIVE PRECIPITATION FORECAST (PQPF) HYDROGRAPHS 6
Probabilistic Quantitative Precipitation Forecasts PQPF Forecasts Are: Helpful for sizing up potential basin response Unofficial raw model guidance PQPF Forecasts Are Not: Not Quality Controlled by a Forecaster Not a substitute for the official NWS River Forecast Not available at all locations Probabilistic Quantitative Precipitation Low Confidence Forecast preview.weather.gov/edd/ Probabilistic Quantitative Precipitation Higher Confidence Forecast preview.weather.gov/edd/ 7
Probabilistic Quantitative Precipitation Forecast Hydrographs preview.weather.gov/edd/ Layer Tree: Layers -Rivers -RFC QPF Ensemble HYDROLOGIC ENSEMBLE FORECAST SERVICE (HEFS) Hydrologic Ensemble Forecast Service Forecast Process 8
Hydrologic Ensemble Forecast Service Short-Range River Forecast Uncertainty water.weather.gov Initial Experimental HEFS product depicts the uncertainty in short-range river forecasts Probability bands Median (50%) 25-75% 10-90% 5-95% 7 WGRFC locations on AHPS 123 national locations on AHPS New river service locations will expand throughout 2017 to 2018 IMPACT-BASED DECISION SUPPORT SERVICES BELOW CRITERIA Impact: Water is within the banks of the river with no impacts to the surrounding area. Flow speeds may still be high during rainfall or releases which could impact recreational activities ACTION Impact: Water is over the banks and into the flood plain, but not a threat to structures or roadways. Some action may be required such as moving farm equipment or increasing awareness MINOR Impact: Typically water is impacting areas inside of flood plain which can vary by location. Some low water crossings covered by water, agricultural flooding, water approaching public areas (parks, sidewalks etc.). Areas frequently flooded can expect to be impacted MODERATE Impact: Water now reaching areas only impacted by significant rain events. Structures can be inundated, several roads covered with water, water may cut off certain areas, widespread agricultural flooding MAJOR Impact: Water is near the highest its ever been representing rare flooding and significant widespread impacts. Most roads will be covered by water in the area cutting off if not completely flooding subdivisions, rivers can be several miles wide in areas. Homes and structures underwater, bridges inundated and in danger of being hit by debris. Impacts may be greater than ever experienced. 9
Recent Changes WGRFC Management overhaul in 2015 New paradigm Relevant, Reliable, Responsive IDSS Impact Decision Support Services Be the water expert Supplemental graphics Don t lose sight on required duties WGRFC and IDSS 2015-2016 Special images Event specific Can be used for FB posts or tweets Used to brief regional and national, both internal NWS and external interests Why create these special images? "Out of everything that was briefed on the call that is the most valuable piece of information TX State SOC Manager NATIONAL WATER MODEL 10
National Water Model NWM V1.0 System Flow 1/1. NWM Forcings Engine (NWS numerical weather models and observations) (avg. size ~1mi 2 ) 31 Now National Water Model vs. Lumped Hydrologic Model The Future NHDPlus reach catchment Uniquely labeled across nation 15 Forecast Groups 320 Forecast Locations Almost 600 Modeled Watersheds 102,000 NHDPlus reach catchments for Texas Average area 7.1 km 2 Average reach length 3 km National Water Model water.noaaa.gov Plots Anomalies 11
National Water Model v1.0 Raw Model Results & Verification water.noaaa.gov Questions/Comments? Gregory Waller Service Coordination Hydrologist NWS West Gulf River Forecast Center greg.waller@noaa.gov Kris Lander, PE, CFM Development and Operations Hydrologist NWS West Gulf River Forecast Center kris.lander@noaa.gov 12