Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
303 AM EST Thu Jan 1 2026
Day 2
Valid 12Z Fri Jan 02 2026 - 12Z Sat Jan 03 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
CALIFORNIA...

An expansive upper level cutoff low over the Pacific well west of
the northern California coast will approach the northern California
coast Friday night. The occluded front wrapping around a surface
low will be the primary forcing for heavy rainfall into northern
California Friday night. The occluded front will turn the flow a
bit more onshore (southeast before the front to south-southwest
behind it). This will allow the coastal ranges to upslope some of
that moisture, locally enhancing rainfall rates, particularly into
the northern Coastal Ranges and the Klamath Mountains. Some heavy
rain may impact the Bay area and the coastal ranges south from
there in the waning couple hours of the period, assuming the timing
of the front moving into the coast remains unchanged. IVT values
between 500 and 750 kg/ms are far from impressive, and moisture
anomalies rise to around 2 sigma above normal, a common occurrence
in this part of the world, especially the past few weeks. Thus,
with the rainfall event just getting going, coming in in the middle
of the night, and with less-than-impressive dynamics, the Marginal
Risk for much of the central and northern California coast remains
largely unchanged with this update, and the Marginal looks on
track.

Wegman

Day 2 threat area: www.wpc.ncep.noaa.gov/qpf/98epoints.txt