714
AGUS76 KRSA 181425
HMDRSA

Hydrometeorological Discussion
National Weather Service / California Nevada RFC / Sacramento CA
730 AM PDT Sat May 18 2024

...ISOLATED SHOWERS/T-STORMS OVER THE SRN SIERRA INTO NV TODAY,
OTHERWISE NO ORGANIZED THREAT OF PRECIP FOR THE REGION...
...GRADUAL COOLING FROM W TO E THIS WEEKEND INTO NEXT WEEK...

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

An upper ridge remains over the eastern Pacific flanked on either
side by two upper lows as a trough approaches the PacNW. The trough
will move through WA later today as the eastern most upper low heads
towards CA. This will set up a troughing pattern over the region
today continuing a cooling trend keeping coastal areas below normal
while beginning to ease temperatures inland. Most of northern CA and
NV will likely remain about 5-10 deg F above seasonal normals for
today. Additionally, this pattern will allow for chances of
showers/thunderstorms over the central/southern Sierra and into NV
this afternoon/evening. QPF amounts should be fairly light at 0.10"
or less with locally 0.25-0.50" possible under thunderstorms. The
trough over the PacNW will dig deeper into the west coast the rest
of the weekend eventually merging with the offshore upper low into
Monday. This will keep the western U.S. in a troughing pattern early
next week allowing for temperatures to cool down closer to seasonal
normals with many areas even 5+ deg F below normal.

Additional systems are forecast to drop into the PacNW throughout
the week keeping the offshore high pressure at bay and allowing for
cooler weather to persist the rest of the period. An upper low
moving into WA/OR on Weds may result in some light showers across
the northern regional border Weds and Thurs with otherwise dry
conditions anticipated. Any resulting showers are not expected to
generate much precip (less than 0.10").

Freezing levels generally 10-13 kft across the region with
occasional lowering to 5-8 kft across far nrn CA/srn OR and nrn NV
as systems pass to the north.


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



AS

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