NOAA National Weather Service

1. NOAA National Weather Service Forecaster’s Workshop Kansas City, MO January, 2010 Tom Gurss Development and Operations Hydrologist Missouri Basin River Forecast Center http://www.crh.noaa.gov/mbrfc tom.gurss@noaa.gov

2. Today’s Presentation • General overview of MBRFC • Typical products and services • Overview of hydrologic model • Timeline of Forecasting Processes • Possible Collaboration

3. NWS River Forecast Centers • MBRFC is just one of 13 RFC’s across the US • Coverage based on watersheds

4. MBRFC Area of Responsibility • 530,000 square mile drainage area • 25 major river basins • 21 WFOs served • 547 stage forecast locations • 78 reservoir inflow forecast points • 174 headwater forecast locations • 28 WSR-88D radars

5. MBRFC Area of Responsibility 25 Major River Basins Upper Missouri River Big Horn River Yellowstone River Milk River Upper Dakota Tributaries Middle Dakota Tributaries Lower Dakota Tributaries North Platte River South Platte River James/Vermillion Rivers Big/Little Sioux Rivers Loup River Elkhorn/Platte River Upper Missouri Tributaries Upper Republican River Upper Smoky Hill River Lower Republican River Lower Smoky Hill River Big Blue River Kansas River Marais Des Cygnes River Osage River Lower Missouri Tributaries Grand/Chariton Rivers Missouri Mainstem 4 1 5 3 9 2 6 1 0 7 1 1 1 2 1 3 8 1 8 1 4 2 3 1 6 1 9 1 7 1 5 2 4 2 0 2 1 2 2

6. MBRFC Area of Responsibility 21 National Weather Service offices Serviced Great Falls, MT Billings, MT Glasgow, MT Bismarck, ND Cheyenne, WY Riverton, WY Rapid City, SD Aberdeen, SD Sioux Falls, SD North Platte, NE Hastings, NE Omaha, NE Denver, CO Goodland, KS Dodge City, KS Wichita, KS Topeka, KS Des Moines, IA Pleasant Hill, MO St. Louis, MO Springfield, MO

7. MBRFC Area of Responsibility Forecast Point Locations

8. MBRFC Staff 19 staff members • Hydrologist-in-charge • Development and Operations Hydrologist • Service Coordination Hydrologist • 1 Senior HAS Forecaster • 4 Senior Hydrologists • 10 Hydrologists • 1 Administrative support assistant

9. MBRFC StaffingHours of Operation • RFC staffed from 6:30 AM - 10:00pm every day • Day Shift 6:30 AM - 4:00 PM • Evening Shift 2 PM - 10 PM • Hours of operations extended as conditions warrant

10. What the RFC Does Provides Hydrologic support to WFOs and other agencies in the form of: • Flood Forecasts • Daily Stage Forecasts • Contingency Forecasts • Headwater / Flash Flood Guidance • Water Supply Forecasts • Long Range Probabilistic Forecasts • Spring Snowmelt Outlooks • Reservoir Inflows • Gridded QPE and QPF • Flood Outlook Product

11. Data RequirementsObserved and future • Precipitation • Temperature • Snow depth and water equivalent • Reservoir pool and outflows • Diversions

12. Data Forcings • Precipitation • Hourly reports used to create biases for radar estimates and time distribute 24 hr reports • 24-hr reports used to further adjust hourly MPE estimates • Create 6-hr grids of QPF out 120 hours. Only 24 hours of QPF currently used in forecasts • Typed as snow based on temperature

13. Data Forcings • Temperature • 3-hr reports from synoptic stations • Max/min reports for other stations • 7-day future temperature max/min provided by WFO • 8-10 day future temperature provided by CPC • Model uses climatology beyond 10 days

14. Data Forcings • Regulation • Use observed and forecast data wherever available • Some sites use last value • Some sites use modeled regulation based on available flow, date, pool elevation, antecedent precip, temperature

15. Hydrologic Model • 6-hr Lumped model of ~1400 basins • Snow-17 • Sacramento Soil Moisture Accounting Rainfall/Runoff • Unit Hydrograph • Hydrologic Routings • Stage-Discharge Ratings • Regulation Models

16. Snow-17 Model • The model uses computed mean areal precipitation including future precip and temperature time series as input and produces time series of rain-plus-melt as output. • The rain-plus-melt time series becomes the input to the SAC-SMA model.

17. Snow-17 Model

18. Snow-17 Model • Run-time Modifications to Snow model states or Rain+Melt output • WECHNG or WEADD mod--change water equiv • AESCHNG mod--change areal extent of snow • RAINSNOW mod--change rain to snow • MFC mod--change rate of melt due to varied conditions • RRICHNG—change value of rain + melt • RRIMULT—factor rain + melt

19. Sacramento Soil Moisture Accounting Model • Uses mean areal rain+melt time series including future precip as input. • Generates mean areal runoff as output. • Conceptual model divides the soil mantle into upper and lower zones. • Both upper and lower zones are divided into ... • Tension water component • Free water component • Frozen ground accounted for

20. Sacramento Soil Moisture Accounting Model • Water moves over, through or out of soil by: • Evaporation and evaportranspiration from tension water zones • Percolation from upper zone to lower zone • Transfer from free water to tension water during dry periods with high evaportranspiration • Runoff

21. Sacramento Soil Moisture Accounting Model

22. Sacramento Soil Moisture Accounting Model • Potential Evaporation and Evapotranspiration defined with ET demand curve • Daily ET demand is interpolated from monthly ET values • Daily ET demand values will vary from observed values depending on temperature, wind, solar radiation, etc

23. Sacramento Soil Moisture Accounting Model Run-time Modifications to SAC-SMA model states or output runoff: • SACBASEF mod—factor contents of baseflow buckets • SACCO mod--change contents of any bucket • ROCHNG—change value of runoff • ROMULT—factor values of runoff

24. Hydrologic Model Runoff from each basin computed and routed downstream: • Runoff applied to unitgraphs • Flow routed from basin to basin using Lag/K, Tatum, or Muskingum routings • Flow adjusted at each gage site based on current stage and rating • Forecasted flow converted to stage based on current rating

25. Hydrologic Models Unit Hydrograph When the runoff is not distributed evenly over the basin, you can expect the response to deviate from the typical unit hydrograph.

26. Stage/ Discharge Ratings • Ratings shifted based on measurements or based on need to balance flows between gage sites • Flows periodically compared to Corps and USGS flows for consistency • Try to stay consistent with either USGS or Corps, however sometimes have to vary some to make stages match in the model.

27. Regulation Modeling • Reservoirs • Diversions • Returns • Some use last data, some are modeled

28. Deterministic Forecasts

29. Probabilistic forecasts • The models simulate the current soil moisture conditions, snow cover, etc. • Using historical precipitation and temperature data, the watershed model can determine “what if” scenarios • Given today’s soil moisture and snow cover states, apply historical 6-hr temp and precip from each year in the record to create multiple future hydrographs. • Statistically analyze the ensemble of future hydrographs to create probabilities of certain events

30. Hydrograph Ensembles are the basis for all Probabilistic products.

31. Probabilistic Product

32. Statistical Water Supply Issued the first week of the month in collaboration with NRCS Based on regression analysis mostly relating snowpack at the first of the month with historical observed flows Products include estimated SWE and likely volume of flow until the end of the melt season

33. Water Resource Outlook Website has both statistical water supply outlooks and ESP outlooks. Outlooks aren’t exactly the same Current website is Western Water but will be migrating to new website within the next couple of months. Allows user to track previous outlooks Provides one stop shopping

34. Missouri Basin River Forecast Center Observed Period Estimated Precipitation

35. Missouri Basin River Forecast Center Forecast Precipitation

36. Flash flood guidance

37. QPF ENSEMBLE FORECASTS Raw Model Output

38. Chronology of Forecasting Events 6:30-8:30 Review and manually adjust hourly Multisensor Precip Estimates ending at 12z. Automatic estimates every hour at about :20. Transfer to ldm for Corps every hour at :32. 6:30-7:00 Review and adjust QPF. Copy to ldm for Corps whenever QPF is run. 6:45 Automatic run of all rivers. Missouri River flows provided to NCRFC 7:00-9:30 Missouri River and tributaries models updated adjusting model states and inputs as needed. Forecasts issued for tributaries. Missouri River flows updated and provided to NCRFC whenever model rerun. Call Corps as necessary to get gate changes.

39. Chronology of Forecasting EventsContinued 7:20 Retrieve Reclamation data 8:20 Retrieve Corps RCC reservoir report 8:30-9:30 Releases for Bagnell Reservoir on Osage River provided by Ameren Power, typically well after 9:00 9:00-10:00 Issue Kansas and Missouri River daily forecasts. Products provided Corps every 10 minutes 9:10 Provide daily precipitation report to Corps via email 9:30, 10:00 Provide Missouri River tributary flows to Corps 10:00-10:30 Issue Flash Flood Guidance

40. Chronology of Forecasting Events Continued 10:16 Begin retrieving Kansas City Corps bulletin and reservoir release forecasts 10:35 Retrieve Omaha District bulletin 10:20 Provide QPF ensemble scenario forecasts to NCRFC, WFOs and Corps 11:00 Retrieve Missouri River forecasts from Corps RCC 11:15 Retrieve Reclamation inflows Update forecasts as necessary 12:00 Update QPF Midafternoon—Update forecasts as required

41. Chronology of Forecasting Events Continued QC hourly QPE grids 7:00 PM Issue Evening Flash Flood Guidance 7:00-10:00 PM Update forecasts as necessary 10PM-6AM Monitor and update flood forecasts as necessary

42. CHPS/FEWS • New Forecast System • Basic Hydrology the Same • Capability for adding new operations • RES-SIM, HEC-RAS, Distributed model

43. Collaboration • Regulation Modeling • Snow data • Forecasted operations • Ratings • Improved data sharing methods • Climate change studies

44. NATIONAL WEATHER SERVICE MISSOURI BASIN RIVER FORECAST CENTER http://www.crh.noaa.gov/mbrfc/ Tom Gurss Tom.gurss@noaa.gov