976 
FOUS30 KWBC 250008
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
708 PM EST Tue Feb 24 2026

Day 1
Valid 01Z Wed Feb 25 2026 - 12Z Wed Feb 25 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
NORTHERN SIERRA NEVADA MOUNTAINS AND ADJACENT FOOTHILLS...

Changes to continuity were to shave off some of the northern portion
of the risk areas where heavy rainfall should no longer be a
factor after 01z. The plume of moisture moving into northern 
California has brought with it much warmer air. Snow levels have 
risen to between 8,000 and 10,000 ft. These much higher snow 
levels moving over the mountains that have multiple feet of new 
snow on them from the storms the past few weeks is leading to 
accelerated snow melt. As the rain falls on the snow pack, much of
it will be absorbed. However, snowfall at the edges of the mountain
snowpack could convert to runoff as heavy rainfall accelerates 
snow melt. Instances of flash flooding, particularly in the Slight
Risk area of the northern Sierra Nevada mountains and adjacent 
foothills, remains possible through 03z/7 pm PST, after which 
rainfall intensity should fade.  Due to snowmelt, flooding could 
continue beyond that. Somewhat lesser rainfall amounts are expected
into the northern coastal ranges. There is also significantly less
snowpack in the coast ranges, so there will be less snow to melt 
and turn into runoff in that area. 

Roth


Day 2
Valid 12Z Wed Feb 25 2026 - 12Z Thu Feb 26 2026

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Oravec

Day 3
Valid 12Z Thu Feb 26 2026 - 12Z Fri Feb 27 2026

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Oravec




Day 1 threat area: https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt
Day 2 threat area: https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt
Day 3 threat area: https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt