Maximum Unit Streamflow - Warning Decision Training Division (WDTD)

Navigation Links

Products Guide

Maximum Unit Streamflow

Short Description

Normalization of the maximum streamflow product by basin area at every grid point from a period of 30 minutes prior to model runtime out to 12 hours after model runtime

Subproducts

CREST, SAC-SMA, and Hydrophobic. The FLASH EF5 framework runs multiple hydrological models using a common input. For MRMS Version 12, there is a maximum unit streamflow product for each of the 3 models listed here.

Primary Users

NWS: WFO, RFC

Input Sources

MRMS Radar-Only QPE

Resolution

Spatial: ~1 km x 1 km

Temporal: 10 minutes

Product Creation

The FLASH EF5 model framework uses MRMS Radar-Only QPE as input into the 3 hydrological models (CREST, SAC-SMA, and Hydrophobic) which then use a subset of these hydrological principles (infiltration, storage, interflow, evapotranspiration, and runoff) to route the precipitation through the basins. The maximum water flow that occurs at any time in each grid point during the model run from a period of 30 minutes prior to model runtime through 12 hours after model runtime is normalized by the basin area and then assigned to each grid point.

Technical Details

Latest Update: MRMS Version 12

NOTE: In version 12, all FLASH products now use the instantaneous rainfall rates from the Dual-pol radar synthetic QPE product.

Accessible on:

Operational AWIPS
1. V11.5 -- MRMS menu
2. V12 -- via LDM, if set-up
MRMS Development site

References

Gourley, J., Z. Flamig, H. Vergara, P. Kirstetter, R. Clark III, E. Argyle, A. Arthur, S. Martinaitis, G. Terti, J. Erlingis, Y. Hong, and K. Howard, 2016: The Flooded Locations And Simulated Hydrographs (FLASH) project: improving the tools for flash flood monitoring and prediction across the United States. Bull. Amer. Meteor. Soc. doi:10.1175/BAMS-D-15-00247.1, in press.

Jiahu Wang, Yang Hong, Li Li, Jonathan J. Gourley, Sadiq I. Khan, Koray K. Yilmaz, Robert F. Adler, Frederick S. Policelli, Shahid Habib, Daniel Irwn, Ashutosh S. Limaye, Tesfaye Korme & Lawrence Okello (2011) The coupled routing and excess storage (CREST) distributed hydrological model, Hydrological Sciences Journal, 56:1, 84-98, DOI: 10.1080/02626667.2010.543087

Strengths

By modeling the water cycle using these more robust state-of-the-science hydrological models, flash flood prediction becomes more objective and scientifically sound.

By normalizing the maximum streamflow product based on basin area, it becomes easier to identify areas most prone to flash flooding (e.g. relatively high flows in small basins)

Limitations

All limitations associated with MRMS Radar-Only QPE apply

Significant amounts of snowmelt are not accounted for in this version of FLASH

FLASH model does not account for river diversions such as dams

Rainfall forcing is stopped at the model initialization time

Quality Control

This product is subject to the MRMS 3D Reflectivity Cube quality control (QC) process.

Applications

Diagnose areas of potential flash flooding

Example Images

Here is the maximum unit streamflow for Houston on May 26, 2015. Notice there are broad areas of greater than 2 m3/s/km2 (185 cfs/mi2) and some localized areas with values greater than 10 m3/s/km2 (915 cfs/mi2).