An MFP alternative consists of an HEC-HMS meteorological 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. From the HEC-RTS main window, click the Setup tab, from the Models menu, point to Import, click MFP, and the Choose MFP Version dialog (Figure 1) opens.
   
2. Select the MFP version to import from in the list (Figure 1). Available import version choices for MFP alternatives are Versions 2.1 and 3.x.
3. Click OK, the Choose MFP Version dialog (Figure 1) closes, and the Select MFP project file to import from browser will open.
4. For MFP Version 2.1, navigate to and select the MFP project file (.conf) you want to import, click Open.
5. For MFP Version 3.0 or higher, navigate to and select the folder containing the MFP project file (.mfp) you want to import, click *Open.
6. The Select MFP project file to import from browser will close. An Importing progress bar will display, once that closes, an MFP model alternative(s) is imported into the watershed. Save your watershed.

Create an MFP Alternative

To create an MFP alternative:

1. From the HEC-RTS main window, click the Setup tab, from the watershed tree, from the Model folder, right-click MFP, from the shortcut menu, click New.
2. The Create New MFP Alternative dialog (Figure 2) opens. Enter a name in the Name field and enter a description in the Description field (Figure 2).
   
3. From the Basin Model list (Figure 2), select a basin model. The choice of basin model will determine which precipitation zone configurations will be available for the MFP alternative. 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.
4. From the Meteorologic Model list (Figure 2), select a meteorologic model. The meteorologic model determines the grids used in the lookback portion of the forecast.
5. From the Precipitation Zone Configuration list (Figure 2), select a precipitation zone configuration.
6. Click OK, the Create New MFP Alternative dialog closes. To edit the newly created MFP alternative, from the HEC-RTSI main window, click the Setup tab, from the watershed tree, from the Model folder, right-click on the newly created MFP alternative. From the shortcut menu, click Edit Alternative, the MFP Alternative Editor opens (Figure 3).

By default, the MFP Alternative Editor (Figure 3) is set for manual entry of forecast precipitation data by precipitation zone. If you have QPF data available, (DSS file) you can enter the data by choosing one of the QPF options.

To add precipitation data for the selected precipitation zone configuration:

1. From the MFP Alternative Editor (Figure 3), select the precipitation zone configuration from the Zone Configuration list.
2. Setup your time window. By default, Relative Start Time is selected.
   
3. From the Duration of Future Precipitation list (Figure 3), select the duration for 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 (Figure 3) closes.
5. From the File menu, click Save Watershed.

MFP Precipitation Zone Configurations

A precipitation zone configuration is required to create an MFP alternative. A zone configuration is a set of zones, 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. From the MFP Alternative Editor (Figure 3), from the Edit menu, click Zone Configuration. The Zone Configuration Manager dialog (Figure 4) opens.
   
2. Click New, the Create a New Zone Configuration dialog (Figure 5) opens.
   
3. From the Create a New Zone Configuration dialog, enter a name in the Name field and a description into the Description field.
4. From the Element Type list (Figure 5), 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 (Figure 4) select the newly created zone configuration.
2. Click Zones, the Zones dialog (Figure 6) opens.
   
3. Click New, the Create A New Zone dialog opens (Figure 7). Enter a name in the Name field and description into the Description field. Click Create, the Create A New Zone dialog closes. The name of the zone you just created displays in the Current subbasin zones for selected zone configuration list on the Zones dialog (Figure 6). Close 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 (Figure 4) select the zone configuration you want to configure.
2. Click Elements, the Elements dialog (Figure 8) opens. From the Zones list (Figure 4), select which zone you want to add elements to.
   
3. Now you need to define the elements (subbasins or reaches) that are part of the selected zone. For example, in Figure 8, from the Unassigned Subbasins list you will be selecting a subbasin(s) to add to the selected zone. You can select individual element(s); select ranges of subbasins by shift-clicking; select discontinuous groups of subbasins by control-clicking; or, double-click on element. Click Add, the selected subbasin names will now display in the box that is under the Zone list (Figure 8).
4. 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.
5. When you have finished assigning elements to zones, close the Elements dialog (Figure 8). Then close the Zone Configuration Manager (Figure 4).

Define a QPF Transform 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. There are two types of QPF data that are available from the National Weather Service or from other sources. One type is point QPFs, which consist of a time series of forecasted precipitation depths at a single location. The second type is 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 24-hour total following the four 6-hour increments. It is necessary to disaggregate these totals into increments that match your modeling time step.

To use QPFs in your forecast model, from the MFP Alternative editor (Figure 3), select either Time Series or Gridded. Each option (Manual, Time Series, or Gridded) presents a different form of the forecast precipitation table. If you select Time Series, the table appears as shown in Figure 9, 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.

If you select Gridded, the table appears as shown in Figure 10 and once you have defined your QPF data, the table will be filled with the disaggregating weights (not the precipitation values themselves).

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

1. From the MFP Alternative Editor (Figure 3), from the Edit menu, point to Precip Transformation Set, click New.
2. The Create a New Precipitation Transformation Set dialog opens (Figure 11). 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, the Transformation Editor (Figure 12) opens. From the Transformation Editor, you can specify the Output Time Interval and the Input Time Interval. The Transformation Editor (Figure 12) 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.
   
4. 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 Transformation Editor closes (Figure 12).
5. To associate a QPF time series record with a zone, from the MFP Alternative Editor dialog (Figure 3), click Time Series. Select a row in the table and click Pathname.
6. The Set Locations for DSS Connections dialog (Figure 19.20) opens. To open a DSS file, click .
   
7. From the Open File browser, locate and open the appropriate DSS file. The lower table will be filled with the 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.
8. Once you click OK, the MFP Alternative editor (Figure 3) will read the DSS file and try to find the QPF data.

Edit an MFP Alternative

To edit an MFP alternative:

1. From the watershed tree (Figure 14), under the Models folder, expand the MFP folder (Figure 14). Right-click on the MFP alternative you wish to edit.
2. From the shortcut menu (Figure 14), click Edit Alternative, the MFP Alternative Editor (Figure 3) opens.
   
3. Use the MFP Alternative Editor to make changes to the MPF alternative you are editing.
4. Click the OK, and the MFP Alternative Editor closes.

Copy an MFP Alternative

To copy an MFP alternate:

1. From the watershed tree (Figure 14), under the Models folder, expand the MFP folder (Figure 14). Right-click on the MFP alternative you wish to edit.
2. From the shortcut menu (Figure 14), click Save As, the Save MFP As dialog (Figure 15) opens.
   
3. Enter the new name in the Name field and fill out the Description field. (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, from the watershed tree (Figure 14), under the Models folder, expand the MFP folder (Figure 14). Right-click on the MFP alternative you wish to edit. From the shortcut menu (Figure 14), click Delete, a Confirm Delete window (Figure 16) opens. Asking you are you sure you want to delete the selected MFP alternative. Click Yes, the Confirm Delete window (Figure 16) will close. The MFP alternative is no longer displayed under the MFP folder.