Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
256 PM EST Thu Nov 20 2025
Day 2
Valid 12Z Fri Nov 21 2025 - 12Z Sat Nov 22 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
SOUTHEAST California AND SOUTHWEST ARIZONA...

20Z Update: Little to no changes to the previous forecasts as the
overall synoptic pattern maintains continuity with little run-to-
run variance in both the QPF presentation and evolution.

Kleebauer

..Previous Discussion..

Model guidance continues to lift the Plains system northward into
portions of the Ohio Valley. Above normal levels of moisture being
transported into the region from the south and encountering an east
to west oriented boundary...there is still the possibility for
isolated areas of moderate to heavy rainfall that leads to spotty
problems from run- off. However...the flow aloft becomes
increasingly flat and confluent during the day which will reduce
the risk of any excessive rainfall.

In California...we will carry a Slight risk across portions of the
desert areas of southeast CA into southwest AZ. Lobes of vorticity
east of the closed low will produce periodic rounds of showers and
embedded thunderstorms. Instability looks pretty weak, which will
likely be a limiting factor, however some brief heavier rates are
still possible from short training segments within the deep layer
southerly flow.

Bann/Chenard

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