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Products Guide

Multi-Sensor QPE

Multi-Sensor QPE

Short Description

Multi-Sensor QPE supplements radar data with combination of gauges and NWP QPF (HRRR/RAP blend for CONUS) to gap-fill in poor radar coverage areas. The Multi-Sensor QPE is available in two products: Pass 1 and Pass 2. Pass 1 is available first, but with less gauges included. Pass 2 has a higher latency, but with most gauges included.

Subproducts

1-, 3-, 6-, 12-, 24-, 48-, and 72-hour accumulations

  • Multi-Sensor QPE Pass 1 -- less latency, but less gauges
  • Multi-Sensor QPE Pass 2 -- more latency, but more gauges

Primary Users

NWS: WFO, RFC

Input Sources

Radar QPE w/ Gauge Bias Correction, Mountain Mapper QPE, NWP model QPF (varies based on domain), HADS and MADIS gauge networks

Resolution

Spatial resolution: 1km x 1km

Temporal resolution: Updated hourly at the top of the hour. All products end at the indicated time.

  • Multi-Sensor QPE Pass 1 -- 60-min latency, 60-65% of gauges included
  • Multi-Sensor QPE Pass 2 -- 120-min latency, 99% of gauges included

Product Creation

The Multi-Sensor QPE is based on a decision tree that determines which input product shall be assigned at each grid cell: Radar QPE w/ Gauge Bias Correction, Mountain Mapper QPE, or NWP model QPF. These decisions are based on radar coverage (via RQI), the precip type environment, and topography. The preferred input is the Radar QPE w/ Gauge Bias Correction, with the other two inputs supplementing in areas where radar coverage is poor. 

Technical Details

Latest Update: MRMS Version 12

Accessible on:

 

Description of flow chart below

There are significant radar coverage gaps across the western CONUS and in other MRMS domains (e.g., Alaska). To supplement the radar data, the new Multi-Sensor QPE utilizes a combination of gauges (via Mountain Mapper QPE) and NWP (HRRR/RAP blend for CONUS) to gap-fill in poor radar coverage areas.

  1. The logic uses the Radar QPE w/ Gauge Bias Correction as the primary precipitation source with its weight in the scheme defined by the RQI product.
  2. Beyond the areas using radar coverage, the combination of Mountain Mapper and NWP are dependent on a number of variables.
    1. NWP (via the 1-h forecast QPF) is utilized in snow environments and also in stratiform rain environments over areas of non-complex terrain.
    2. Mountain Mapper QPE is utilized in areas of stratiform rain over areas of complex terrain.
  3. Each source is seamlessly blended to avoid any discontinuities in the data. 

 

NWP Model QPF Details

Below are the NWP models used as input to the Multi-Sensor QPE products, as of Spring 2020:

Domain NWP Model QPF
CONUS HRRR_CONUS

Alaska

HRRR_AK exper.
Hawaii HRRR_HI exper. --> coming soon!
Caribbean No Multi-Sensor QPE products
Guam No Multi-Sensor QPE products

 

Domain Considerations

It’s worth pointing out that these Multi-Sensor products are implemented differently depending on the domain. This table quickly summarizes this information.
 

References