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AGUS76 KRSA 072108
HMDRSA

Hydrometeorological Discussion
National Weather Service / California Nevada RFC / Sacramento CA
130 PM PST Fri Feb 7 2025

...LINGERING SHOWERS INTO THIS EVENING MAINLY OVER NEAR ORCA BORDER
AND ALONG THE COAST AND PORTIONS OF SRN CA AND OVER THE SIERRA AND
INTO NV THEN MAINLY DRY AND COOL OVER THE WEEKEND INTO MONDAY EXCEPT
LIGHT PRECIP POSSIBLE OVER NW CA AND SRN OR CASCADES SATURDAY...

...LIGHT PRECIP POSSIBLE TUESDAY THEN MORE WIDESPREAD PRECIP
POSSIBLE MID-LATE NEXT WEEK...

.METEOROLOGICAL CONDITIONS (SHORT TERM: FRI PM - MON AM)...

Little to no change to the afternoon forecast with lingering showers
into tonight and mainly light precip over NW CA coast and Srn OR
Cascades and NE NV on Saturday and dry forecast for Sunday.

Upper level shortwave trough moving through the region this
afternoon into evening. Lingering scattered showers possible this
afternoon then tapering off overnight. Highest precip amounts
generally expected along the Sierra and over Srn CA (San Gabriel and
San Bernardino Mtns and south) and NE CA plateau and over higher
terrain of Ern NV with 0.1-0.6 inches except locally around an inch
for the San Bernardino Mtns. Another shortwave trough moves through
the Pac NW and brushes far Nrn CA and Nrn NV on Saturday. Mainly
light precipitation less than a quarter of an inch is possible along
the NW CA coast and Srn OR Cascades and possibly a few hundredths
into NE NV higher terrain on Saturday. Freezing levels around 2000-
4000 ft near ORCA border and around 4000-5000 ft for Nrn Sierra and
5000-6000 ft Central Sierra and 5500-7500 ft for Srn Sierra and 9000-
12000 ft over Srn CA and around 4000-9000 (N-S) over Nevada today
and fluctuate near similar levels on Saturday.  A weak broad trough
digs into the region on Sunday with dry conditions expected.

Max temperatures near to around 10 degrees below normal
over most of the region except up to 10 degrees above normal over SE
CA and Srn NV. On Saturday, max temperatures generally below normal
up to 15 degrees except near normal SE CA and far Srn NV . Min
temperatures 5 to 15 degrees below normal over Nrn CA and near normal
to 10 degrees below normal for Central CA and most of NV near normal
to 10 degrees above normal for Srn CA (especially SE). Max
temperatures generally near normal to 20 degrees below normal for the
region on Sunday. Min temperatures 5 to around 20 degrees below
normal over Nrn CA and 5 to 15 degrees below normal for Central CA
and NW NV and near normal to 10 degrees below normal for Srn
CA (except far SE CA) and Srn and Eastern NV.


.METEOROLOGICAL CONDITIONS (LONG TERM: MON AM - THU AM)...

Still anticipating a dry Monday as dry west to northwest flow is
situated along the west coast with a weak disturbance moving toward
northern Baja...while a polar continental s/wv trof moving from
western Canada will make its way toward the Pacific Northwest before
reaching CA and NV and swinging to the east over the interior. Still
only anticipating some very light precip on Tuesday associated with
this system moving in from the north as available moisture will be
minimal. Measurable precip looks to remain along coastal
locations...the Sierra...and parts of NV. This system will usher in
a colder airmass that will push freezing levels anywhere from 1000-
feet north to 2000- to 4000-feet central and 5000- to 7000-feet
south. Finally into the middle portion of the week...questions still
remain on the timing and trajectory of the s/wv trof moving along
40N toward the west coast...and the entrainment of a lower latitude
moisture plume from near or east of Hawaii. Given this uncertainty
amongst the operational models...used the previous forecast along
with a blend in of the latest WPC QPF and 07/19Z NBM. This did end
up increasing amounts along coastal locations and the southern
Cascades and length of the Sierra to show totals mainly from 0.75-
to 1.50-inches with some localized coastal totals of 2.00-inches.
The warmer airmass associated with this system will start to
increase by the end of the period with 3000-feet far north...to
about 8500-feet for coastal central/southern CA.

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



Osborne/Kozlowski

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