FOUS30 KWBC 140829
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
329 AM EST Sat Dec 14 2024

Day 1
Valid 12Z Sat Dec 14 2024 - 12Z Sun Dec 15 2024

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF 
COASTAL CALIFORNIA FROM SANTA ROSA INTO SAN Francisco AND SAN JOSE...

Even though a much of the areal coverage of moderate to locally
heavy rainfall associated with an atmospheric river has already
moved on shore...maintained the Slight risk area mainly along the
coast from Santa Rosa southward into San Francisco and San Jose
given an expected up-tick in rainfall rates as a compact shortwave
trough approaches from the west. Short term guidance from the
convective allowing mesoscale guidance shows several hundred Joules
per kilogram of CAPE moving into that portion of California
immediately ahead of the shortwave impulse. The 14/00Z HREF
maintained a nearly 100 pct chance of half-inch per hour rainfall
rates and nearly 40 percent chance of 1 inch per hour rates over
and near the San Francisco Bay area during the early- to mid-
morning hours. The combination of the rainfall rates and the
urbanization of the area still points to an elevated risk of flood
impacts. The overall impacts should be limited by the fairly short
duration of heaviest rainfall...which looks to taper off quickly in
the 15Z to 18Z period.

Bann


Day 2
Valid 12Z Sun Dec 15 2024 - 12Z Mon Dec 16 2024

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

Bann


Day 3
Valid 12Z Mon Dec 16 2024 - 12Z Tue Dec 17 2024

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

Bann
$$
--- SBBSecho 3.20-Linux
 * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)