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AGUS76 KRSA 261325
HMDRSA

Hydrometeorological Discussion
National Weather Service / California-Nevada RFC / Sacramento CA
630 AM PDT Sat Sep 26 2026

...CHANCES OF SHOWERS AND T-STORMS OVER SRN NV, SE CA, AND THE
SIERRA SUN-TUE AS A LOW MOVES THROUGH...

.METEOROLOGICAL CONDITIONS (SAT AM - FRI AM)...

Dry conditions across the region today as it sits under a general
troughing pattern. The trough, that is now strengthening offshore,
will continue to deepen into Sunday forming a cutoff low along the
nrn CA coast some time in the late afternoon. The system will then
slide down the coast and head inland into the Bay Area on Monday
moving southeast through central CA in the afternoon before diving
into srn CA/NV in the evening and finally exiting into the Desert
Southwest on Tuesday. This is expected to generate some scattered
showers across the region on Sunday, though with amounts likely less
than 0.10". On Monday, models continue to show some tropical
moisture moving into srn CA along the southern side of the low. This
should bring better chances of more widespread showers and possibly
thunderstorms for Monday, mainly across srn NV, se CA, and the
Sierra. Amounts right now look like like 0.10-0.0.50" for parts of
srn/eastern NV/CA and 0.10" or less elsewhere (higher totals
possible under thunderstorms). Shower chances will diminish on
Tuesday ending by the evening.

High pressure will build in behind the exiting low mid next week
returning dry conditions and above normal temperatures. The GFS does
show another trough approaching the area on Thursday, however, the
ECMWF still has the west coast under a ridge. Looking at the
ensemble 500 mb height clusters, most members are favoring that
ridge.


Please Note: This product may NOT be routinely updated.
Please refer to the following product issued by the CNRFC
www.cnrfc.noaa.gov/Daily-Briefing for a graphical summary of
weather and hydrologic conditions.

QPF graphics are available at www.cnrfc.noaa.gov/qpf.php



AS

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