An MFP alternative consists of an HEC-HMS meteorologic model, a zone configuration (based on an HEC-HMS basin model) and a set of precipitation forecast data. Your HEC-HMS project can contain more than one meteorological model with gridded precipitation from different sources, such as NEXRAD radar, interpolation from gage reports, or results from a grid-based snow model. You will need to create a separate MFP alternative for each source of lookback precipitation grids you intend to use in your forecast models.

Import an MFP Alternative

To import an MFP alternative:

1. In the Setup Module in the Model menu, select Import > MFP, and the Choose MFP Version dialog opens.
   
2. Choose the MFP version to import from in the drop-down box. Available import version choices for MFP alternatives are Versions 2.1 and 3.x.
3. Click OK, and the file browser dialog opens.
4. For MFP Version 2.1, navigate to and select the MFP project file (.conf extension) you want to import, and click the Open.
5. For MFP Version 3.x, navigate to and select the folder containing the MFP project files you want to import, and click Open.
6. The MFP model alternative is imported into the watershed.
7. Save your watershed.

Create an MFP Alternative

To create an MFP alternative:

1. In the Setup tab in the Watershed Pane, from the Model folder right-click MFP.
2. The Create a New MFP Alternative dialog opens.
3. Enter a name in the Name field and enter a description in the Description field.
   
4. Select a basin model from the Basin Model drop-down list. The choice of basin model will determine which precipitation zone configurations will be available for the MFP Make sure to select a basin model that covers the same area covered by any basin models used in MFP alternatives that will combine with this MFP alternative.
5. Select a meteorologic model from the Meteorologic Model dropdown list. The meteorologic model determines the grids used in the lookback portion of the forecast.
6. Select a precipitation zone configuration from the Precipitation Zone Configuration drop-down list.
7. Click OK, and the Create New MFP Alternative dialog closes. To open the MFP Alternative Editor, right-click on the newly created MFP alternative and select Edit Alternative, and the MFP Alternative Editor opens.

By default, the MFP Alternative Editor is set for manual entry of forecast precipitation data by precipitation zone. If you have QPF data available, (extracted from the CWMS database into the forecast.dss file for the forecast) you can enter the data by choosing one of the QPF options. See below for an example of using QPF data.

To add precipitation data for the selected precipitation zone configuration:

1. From the MFP Alternative Editor, select the precipitation zone configuration you wish to configure precipitation data for from the Zone Configuration drop-down list.
2. Setup your time window. By default Relative Start Time is selected.
   
3. Select the duration for future precipitation from the Duration of Future Precipitation This choice sets the number of rows in the table where you will enter values for each precipitation zone of the selected precipitation zone configuration.
4. Enter precipitation data in the table. Values are entered by time step, with each cell representing one time step for the zone. A running total of the forecast precipitation is kept at the bottom of the table. You may want to prepare a set of forecast values with a spreadsheet program and then copy the values from the spreadsheet to the MFP Alternative Editor. Once you have entered your precipitation data, click OK, the MFP Alternative editor closes.
5. From the File menu, click Save Watershed.

MFP Precipitation Zone Configurations

A Precipitation Zone Configuration is required to create a MFP alternative. A Zone Configuration is a set of zones, and a Zone is a set of subbasins in the watershed. In MFP, precipitation forecasts are assigned by zone, with all subbasins in the zone receiving the same precipitation increments. You should group subbasins into zones based on similarity of expected precipitation.

Create a Zone Configuration

To create a precipitation zone configuration:

1. In the MFP Alternative editor, choose Zone Configuration from the Edit The Zone Configuration Manager dialog opens.
   
2. Select New to create a new zone configuration. The Create a New Zone Configuration dialog window opens.
3. From the Create a New Zone Configuration window, enter a name into the Name field and a description into the Description field
4. From Element Type drop-down list, select either Subbasins or Reaches. Click Create, and the Create A New Zone Configuration dialog closes.

Create Zones

For each zone configuration, you will need to create at least one zone. To create a zone:

1. From the Zone Configuration Manager, select the newly created zone configuration.
2. Click the Zones button from the manager window. The Zones dialog opens.
3. Select New and a Create A New Zone dialog opens. Enter a name into the Name field and description into the Description field.
   
4. Select Create, and the name of zone you just created appears in the Current zones for selected zone configuration list on the Zones dialog.

Add Subbasin to a Zone

Once precipitation zones have been created, you can assign elements (subbasins or reaches) to the zones.

1. From the Zone Configuration Manager select the zone configuration you want to configure.
2. Click the Elements button and the Elements dialog opens. From the Zones drop-down list, select which Zone you want to add elements to.
   
3. Select the elements (subbasins or reaches) you want to add to the zone from the elements (subbasins or reaches) listed in the Unassigned Elements list. Select one element by clicking; select ranges of subbasins by shift-clicking; select discontinuous groups of subbasins by control-clicking.
4. Click Add and the selected subbasin names will now appear in the list under the Zone You can also move an element into a zone by double-clicking on the element in the Unassigned Elements list.
5. You can move elements out of a zone by selecting an element in the box under the Zone list and then click Remove or by double-clicking on that element.
6. When you have assigned all elements to zones, close the Zone Configuration Manager.

Define a QPF Disaggregation Set

In place of manually entered precipitation forecasts, MFP permits you to incorporate a sequence of QPF (quantitative precipitation forecast) values into an MFP alternative from an external source.

Two types of QPF data are available from the National Weather Service or from other sources: point QPFs, which consist of a time series of forecasted precipitation depths at a single location, or gridded QPFs, which represent a spatially distributed forecast of precipitation depths. MFP can assign point QPF time series to precipitation forecast zones, or assign a sequence of QPF grids to cover the entire watershed. In either case, QPFs are typically given in six-hour increments covering the next twenty-four hours, and a single twenty-four hour total following the four six-hour increments. It is necessary to disaggregate these totals into increments that match your modeling time step.

To use QPFs in your forecast model, select either Time Series or Gridded by clicking the corresponding radio button on the MFP Alternative editor. Each option (Manual, Time Series, or Grid) presents a different form of the forecast precipitation table.

If you select Time Series, the table appears, and once you have defined your QPF data and defined a set of disaggregating weights, the table will be filled with precipitation increments for the zone.

To assign a HEC-DSS pathname for time series, click the Pathname button. If you select Gridded, the table appears as shown and once you have defined your QPF data, the table will be filled with the disaggregating weights (not the precipitation values themselves). To assign a HEC-DSS pathname for time series, click Pathname.

For either type of QPF data, to define QPF data:

1. You must be in the MFP Alternative editor. Select Edit > Disaggregation Set > New.
2. The Create a New Disaggregation Set dialog opens. In the Name field, enter a name for the QPF distribution set. You can optionally enter a description in the Description field.
   
3. Click New, and the Disaggregation Editor opens.
   
4. In the Disaggregation Editor you can specify the Output Time Interval and the Input Time Interval. The Disaggregation Editor allows you to specify weights for two adjacent blocks of one, six, or twenty-four hours each (based off the Input Time Interval). The weights will be normalized for each block, so the two six hour blocks shown in the example will put half of the six-hour QPF in the third and fourth hours of the six-hour blocks. QPF are referenced to UTC so the blocks will shift according to your watershed’s time zone.
5. Once the disaggregation set is defined, you can associate a QPF time series record with a zone defined in the precipitation zone configurations associated with the MFP alternative. Click OK, the Disaggregation Editor
6. To associate a QPF time series record with a zone, from the MFP Alternative Editor dialog, click Time Series, select a row in the table, and click Pathname.
7. The Set Locations for HEC-DSS Connections dialog opens. To open a HEC-DSS file, click on the folder icon button.
   
8. Using the file browser, locate and open your HEC-DSS file. The lower table will fill be filled with the HEC-DSS catalog information. The top table has the list of precipitation zones for the selected MFP zone configuration. Select a precipitation zone in the top table by clicking on a row. Select a QPF HEC-DSS pathname by clicking on a row in the bottom table. Once a row from each table is highlighted, the HEC-DSS pathname will be assigned to the precipitation zone by clicking Select HEC-DSS Pathname.
9. Once you click OK, the MFP Alternative editor will read the HEC-DSS file and try to find the QPF data.

Edit an MFP Alternative

To edit an MFP alternative:

1. In the Watershed Pane, select the MFP alternative you wish to edit.
2. Right-click the selected alternative and the MFP Alternative Menu is displayed.
3. Select Edit Alternative, and the MFP Alternative editor opens.
4. Use the MFP Alternative editor to make changes to the MPF alternative you are editing.
5. Click the OK, and the MFP Alternative editor closes.
   

Copy an MFP Alternative

To copy an MFP alternate:

1. In the Watershed Pane select the MFP alternative you wish to edit.
2. From the MFP Alternative Menu, select Save As, and the Save MFP As dialog opens.
3. Enter the new name in the Name field and fill out the Description (You can specify the directory where you save the watershed if you wish to save a copy of the alternative to a directory outside of the watershed.)
4. Click OK, and the Save MFP As dialog closes.
   

Delete an MFP Alternative

To delete an MFP alternative:

1. In the watershed pane, select the MFP alternative you wish to delete.
2. From the MFP Alternative Menu, select Delete, and the Confirm Delete of the MFP alternative dialog appears.
3. Click Yes to delete the MFP alternative.