When big storms hit California, current technology does not provide forecasters with the detailed information needed to inform reservoir operations, flood protection, combined sewer-stormwater systems and emergency preparedness. Accurate and timely precipitation information is critical for making decisions regarding public safety, infrastructure operations, and resource allocations.
Standard weather radars, originally designed to look up into Midwest thunderstorms, are often unable to give an accurate picture of what is happening in the complex landscape of California’s coastal mountain ranges. Improved monitoring and prediction of precipitation in the San Francisco Bay region can enhance public safety through early warning and storm tracking when hazardous weather events come onshore.
Advanced Quantitative Precipitation Information (AQPI) is a regional project awarded to NOAA and collaborating partners by the California Department of Water Resources. The AQPI system consists of improved weather radar data for precipitation estimation and short-term nowcasting (0-1 hours); additional surface measurements of precipitation, streamflow and soil moisture; and a suite of forecast modeling systems to improve lead time on precipitation and coastal Bay inundation from extreme storms—especially high-moisture laden atmospheric rivers.
AQPI includes a combination of observations and forecast models to improve prediction of precipitation, streamflow and coastal flooding, which builds on an existing network established by NOAA, DWR and Sonoma Water to monitor extreme precipitation in California. Highlights of AQPI include:
The AQPI System can aid water managers in securing water supplies while mitigating flood risk and minimizing potential water quality impacts to the Bay from storm runoff and combined sewer overflows. The system can be expected to provide benefits exceeding costs by a ratio of at least 4:1. These benefits accrue through:
AQPI builds on over a decade of NOAA research on extreme precipitation in California, including the Bay area. This research has led to an extensive observational network supported by NOAA, the California Department of Water Resources, and the Sonoma Water Agency. Assets from this observational network leveraged by AQPI include: Atmospheric River Observatories, soil moisture, surface meteorology, wind profilers, and snow level radars.
AQPI also includes new observations and forecast modeling to improve monitoring and prediction of precipitation, streamflow, and coastal inundation in the San Francisco Bay region. New AQPI observations:
The seeds of AQPI were sown in the early 2000s with the deployment of advanced instrumentation and research studies focused on understanding extreme precipitation events in the CA coastal range and Sierra as part of NOAA’s Hydrometeorology Testbed (HMT) program. Starting in 2008, NOAA’s Earth System Research Laboratory (ESRL) partnered with the California Department of Water Resources (CA-DWR) to address water resource and flood protection issues. As part of CA-DWR’s Enhanced Flood Response and Emergency Preparedness (EFREP) program, ESRL and CA-DWR are working to improve precipitation monitoring and prediction, especially for extreme events. The statewide deployment of observing systems and suite of highly detailed weather forecast models builds on lessons learned in NOAA’s HMT.
The AQPI concept of using state-of-the-art radars to improve monitoring and short term precipitation forecasts is a natural extension of the HMT and EFREP programs. In 2015 a proposal for a regional implementation of AQPI in the nine county region surrounding the San Francisco Bay area was submitted to a grant solicitation for CA-DWR Proposition 84 under the Bay Area Integrated Regional Water Management Plan, Bay Area Regional Climate Change Preparedness Program. The four year project was awarded by CA-DWR and officially kicked off October 1, 2017. It included funding for five new radar systems, several surface meteorological sites and integration precipitation, streamflow, and coastal flooding information into a system that can deliver data and customized products to end users.