Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
330 AM EST Sun Jan 4 2026
Day 2
Valid 12Z Mon Jan 05 2026 - 12Z Tue Jan 06 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ALONG THE CENTRAL
TO NORTHERN CALIFORNIA COAST AND NORTHERN CALIFORNIA...


There are large scale differences developing day 2 with the
amplification of a closed low in the base of the mean trof off the
Central to Southern CA coast. The NAM and GFS are showing a more
southwest solution compared to the EC, CMC and UKMET. This farther
southwest solution is resulting in a trend of less precip along
the central CA coast to the south of San Francisco and into the
Northern Sierra in the GFS and NAM as the low level flow has a
much weaker onshore component compared to the EC, CMC and UKMET.
Models often struggle with closed formation downstream of
flattening upper ridges with overall low confidence at the moment.
The latest WPC qpf did trend towards less precip across the central
CA Coast Range and over the Northern Sierra, but not as dry as the
GFS and NAM. Subsequently, the previous marginal risk area was
decreased in size. There may be additional changes needed to the
risk area with future model cycles, depending how the evolution of
the closing off mid to upper level center evolves. 

Oravec


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