A powerful storm system brought high winds and heavy downpours to
parts of central and northern California, causing localized
flooding and knocking out power in the San Francisco Bay area.
The weather station on Angel Island in San Francisco Bay measured
strong wind gusts, including one that peaked at 156 kilometers per
hour (98 miles per hour). This storm system was brought in by a
powerful subtropical jet steam, which provided moisture and strong
upper-level winds. The system spawned thunderstorms that brought
lightning and sizeable hail around Sacramento. Coastal regions
also measured heavy rainfall, though there was no widespread
The Tropical Rainfall Measuring Mission (TRMM) monitors rainfall
based on a near-real-time, Multi-satellite Precipitation Analysis
(MPA) at NASA’s Goddard Space Flight Center. This image
shows MPA rainfall totals for the central and northern West Coast
from February 22 to March 1, 2006. The highest rainfall totals for
the period are around 120 millimeters, about 5 inches, shown in
red. These rainfall amounts occur along the western slopes of the coastal range,
in the Klamath Mountains near the border with Oregon, and over the
northern Sierra Nevada on the downwind side of the Sacramento
Valley. The mountains forced moisture from the humid air rising
over the slopes. MPA rainfall totals for the San Francisco Bay
area are rather light, while the areas around Sacramento received
a little over 70 millimeters, about 3 inches, shown in the brighter greens.
The TRMM satellite was launched into service in November of 1997.
It was engineered to measure rainfall over the global Tropics
using both passive and active sensors, including the first and
only precipitation radar in space. TRMM is a joint mission
between NASA and the Japanese space agency, JAXA.