SkyWater Radar

HMT-West Overview

HMT-West is the first regional demonstration of the Hydrometeorology Testbed strategy. It developed as an outgrowth of NOAA's CALJET and PACJET projects (1997-2003), which were aimed at improving short-term forecasting of land-falling storms impacting the west coast of the U.S. Intense precipitation associated with these storms often brings challenges to regional water managers attempting to balance the need for water supply storage and flood mitigation.

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HMT-West brings researchers and operational forecasters together to improve the accuracy and lead time of extreme precipitation and flood forecasts and warnings in the west coast region. Specific objectives include:

Attaining accurate quantitative precipitation estimation (QPE) over the America River Basin with high spatial resolution;
Demonstrating new high-resolution forecast models and model ensembles for quantitative precipitation forecasting (QPF) tailored to the HMT-West domain;
Accurate mapping of important hydrologic forcing parameters (e.g., precipitation intensity, phase, distribution, and depth, standard surface meteorological variables, and soil moisture), and monitoring their evolution; and
Testing and evaluating new observing and numerical modeling tools;

One of the important findings of HMT-West is the recognition that the bulk of heavy precipitation associated with land-falling winter storms often occurs within "atmospheric rivers" (ARs), which are corridors of concentrated water vapor transport in the warm sector region of midlatitude cyclones. HMT-West has fostered a wealth of innovative research to improve our understanding of ARs and has lead to a number of publications.

Since the first full-scale deployment in winter of 2005-2006, the HMT-West effort has focused on the North Fork of the American River Basin, located between Sacramento, CA and Reno, NV on the western slopes of the Sierra Nevada. Water from the American River Basin is a critical resource for California's economy and natural ecosystems, and the threat of flooding poses an extremely serious concern for the heavily populated downstream area. Data from HMT-West and operational sources will be merged in algorithms with the intent to produce multi-sensor (e.g., radar + gauge) QPE. These blended estimates overcome deficiencies inherent in estimates based on single instrument types. Equally important, demonstrations and evaluations of precipitation forecast improvements will be conducted for the American River Basin using high-resolution numerical prediction models, now in use as research tools.

A growing number of local, state, and federal partner institutions and stakeholders are involved with HMT.

Field Experiments

Related Projects

CalWater: Our current understanding of heavy precipitation events and how precipitation will change in a changing climate is hampered by incomplete scientific knowledge. Taking advantage of the infrastructure and knowledge gained through HMT-West, Science leaders from the California Energy Commission, NOAA, and Scripps Institution of Oceanography are identifying gaps, developing strategies, and assisting CEC in planning for a possible follow-up field study.

HMT-West Legacy: An agreement between NOAA and the California Department of Water Resources has led to the deployment of additional instrumentation across the HMT-West domain for long term monitoring of soil moisture, water vapor, precipitation, and snow level across the state of California. These instruments will be deployed in stages over a period of years beginning in 2009. Over time, these observations will create an important climate record and datasets to verify model QPF and improve overall forecast skill.