Severe Thunderstorm Warning 9, NWS Sacramento, CA

Area Forecast Discussion
National Weather Service Sacramento CA
137 AM PST Sat Mar 11 2023

.SYNOPSIS...
Periods of rain with high elevation snow this weekend. Expect
scattered thunderstorms at times both Saturday and Sunday.
Another wet, warmer system early week bringing moderate to heavy
rain, high elevation snow, and renewed flooding concerns.

&&

.Discussion...
Interior northern California radars are in precipitation mode
this early Saturday morning as scattered precipitation impacts the
region. Measurable precipitation over the past 3 hours has mostly
been confined to mountain and foothills locations along/south of
Interstate 80. Radar trends have been slowly increasing over the
last hour, and high-resolution guidance suggests that this will
continue through the night, likely expanding northward as well.

Unsettled weather will continue into the day on Saturday with
scattered to widespread rain and mountain snow showers. 00Z HREF
mean CAPE ranges from 100-600 J/kg from around Interstate 80 and
points south during the afternoon and evening hours today for
Valley and foothill locations. While instability will be decrease
after sunset, there will remain some limited CAPE overnight as far
north as roughly Chico. Strong showers and/or any thunderstorms
that do develop will have the potential to produce locally heavy
rainfall, gusty/erratic winds, small accumulating hail, and even a
small chance of funnel clouds (probability is rather low, but
undoubtedly non-zero). Convection will likely continue into the
day on Sunday with rain showers/thunderstorms as well as mountain
snow showers.

Additional precipitation totals through Sunday will vary from
location to location as is the case with convective activity.
Generally speaking -- the Valley can expect another 0.5 to 1.25
inches of rain, and upwards of another 3 to 4 inches in the
foothills and mountains below the snow line (roughly 5500 to 6500
ft). Some of this rain will fall in locations that have
maintained a deep snow pack over the last several weeks. This will
result in renewed ponding of water issues where the snow pack is
slowing and/or preventing the drainage of liquid water. New snow
accumulations of several feet (or more) will be entirely possible
above the snow level.

Active pattern will continue on Monday as quasi-zonal flow
persists from roughly 40 deg N and points south with troughing
across the northern Pacific. Combination is a classic synoptic setup
for directing a subtropical moisture tap toward the Golden State
(i.e., atmospheric river [AR]). Along the 38 deg N parallel, CW3E
AR toolkit shows the 18Z Fri GEFS ensemble Integrated Vapor
Transport (IVT) mean peaking around 400 kg/m/s while the 12Z Fri
ECMWF EPS mean is higher at roughly 800 kg/m/s for the Tuesday
timeframe. Still some finer details to iron out over the next few
days, but we're undoubtedly still locked into the active pattern
through the middle of the week. // Rowe

&&

.EXTENDED DISCUSSION (Wednesday THROUGH Saturday)...
Lingering showers Wednesday, best chances over the mountains, as
upper level trough exits the forecast area. Drier weather returns
later Wednesday into Thursday as upper ridging moves through.
Another Pacific storm advertised to push into the CWA Friday,
however the system looks weak at this time with limited QPF. First
part of Saturday appears dry under weak short wave ridging, then
another weak storm is possible later Saturday or Sunday.

&&

.AVIATION...
Generally VFR next 24 hrs except areas MVFR/IFR in shwrs. Snow lvls
3000-5500 ft this mrng, rising to 5000-6500 ft by 12 Sun. Isolated
tstms poss btwn 18z-03z. Sfc wind mainly below 12 kts.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Sunday morning for Burney Basin / Eastern
Shasta County-Carquinez Strait and Delta-Central Sacramento
Valley-Motherlode-Mountains Southwestern Shasta County to
Western Colusa County-Northeast Foothills/Sacramento Valley-
Northern Sacramento Valley-Northern San Joaquin Valley-Shasta
Lake Area / Northern Shasta County-Southern Sacramento Valley-
West Slope Northern Sierra Nevada-Western Plumas County/Lassen
Park.

Winter Storm Warning until 9 AM PST Sunday for West Slope
Northern Sierra Nevada-Western Plumas County/Lassen Park.

&&

Special Weather Statement
National Weather Service Sacramento CA
1236 PM PST Sat Mar 11 2023

CAZ018-019-112115-
Carquinez Strait and Delta CA-Northern San Joaquin Valley CA-
1236 PM PST Sat Mar 11 2023

...A strong thunderstorm will impact portions of central San Joaquin
County through 115 PM PST...

At 1235 PM PST, Doppler radar was tracking a strong thunderstorm near
ear Stockton, moving east norteast at 25 mph.

HAZARD...Winds in excess of 40 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible. Funnel clouds are possible.

Locations impacted include...
Stockton, Waterloo, Country Club, Taft Mosswood, Garden Acres,
Kennedy, August, Linden, Morada, Lincoln Village and Lockeford.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 3791 12145 3798 12148 3815 12115 3788 12103
TIME...MOT...LOC 2035Z 254DEG 21KT 3795 12141

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

EK

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SACRAMENTO CA
133 PM PST SAT MAR 11 2023

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1242 PM     HAIL             COUNTRY CLUB            37.97N 121.33W
03/11/2023  M1.00 INCH       SAN JOAQUIN        CA   PUBLIC

            REPORT OF HAIL WITH HAIL STONES UP TO
            QUARTER SIZE IN STOCKTON. TIME ESTIMATED
            FROM RADAR.

&&

CP