189
FSUS46 KLOX 121109
QPSLOX

Quantitative Precipitation Forecast
National Weather Service Los Angeles/Oxnard CA
400 AM PDT Wed Mar 12 2025

Precipitation forecasts in inches are provided in 3-hour
increments until 1700 followed by 6-hour increments until 0500.
Thunderstorm chances cover up to 0500 on day 1 only.

Light rainfall amounts greater than zero but less than a tenth of an
inch are shown as lgt.

The discussion covers the period from: Wed Mar 12 2025 through Tue Mar 18 2025.

&&

                                    05-08  08-11  11-14  14-17  |  17-23  23-05

San Luis Obispo County...

LSRC1:Cambria                          0.0    lgt    lgt    lgt   |   0.8   0.3
SMRC1:Santa Margarita                  0.0    lgt    lgt    lgt   |   0.8   0.3
NIPC1:Lopez Lake                       0.0    0.0    lgt    0.0   |   0.9   0.5

1-Hr Rates:              Coasts/Valleys   Foothills/Mountains
Expected Peak (in/hr):   0.25-0.45        0.15-0.55
Probability 0.50+ in/hr: 40%              60%
Probability 1.00+ in/hr: <5%              <5%

Peak rates expected to occur between: 1800-0000

Chance of Thunderstorms: 20%
Isolated rates around 1.25 in/hr possible near thunderstorms.

&&                                    05-08  08-11  11-14  14-17  |  17-23  23-05

Santa Barbara County...

SIYC1:Santa Maria                      0.0    0.0    0.0    0.0   |   0.6   0.4
SBTC1:Santa Barbara Potrero            0.0    lgt    lgt    lgt   |   0.8   0.9
GBRC1:Gibraltar Dam                    lgt    lgt    lgt    lgt   |   1.2   0.9
SMCC1:San Marcos Pass                  lgt    lgt    lgt    lgt   |   1.3   0.9
SBFC1:Santa Barbara City               lgt    lgt    lgt    lgt   |   0.7   0.7

1-Hr Rates:              Coasts/Valleys   Foothills/Mountains
Expected Peak (in/hr):   0.45-0.55        0.35-0.65
Probability 0.50+ in/hr: 60%              70%
Probability 1.00+ in/hr: <5%              <5%

Peak rates expected to occur between: 2100-0000

Chance of Thunderstorms: 20%
Isolated rates around 1.25 in/hr possible near thunderstorms.

&&                                    05-08  08-11  11-14  14-17  |  17-23  23-05

Ventura County...

FGWC1:Fagan Canyon                     0.0    0.0    lgt    lgt   |   0.2   1.0
HRCC1:Hopper Canyon                    0.0    lgt    lgt    lgt   |   0.2   1.1
MTDC1:Matilija Dam                     lgt    lgt    lgt    lgt   |   0.9   1.1
VTUC1:Ventura City                     0.0    0.0    lgt    lgt   |   0.2   0.8
MORC1:Moorpark                         0.0    0.0    lgt    lgt   |   lgt   0.7
CRXC1:Circle X Ranch                   0.0    lgt    lgt    lgt   |   0.2   1.1

1-Hr Rates:              Coasts/Valleys   Foothills/Mountains
Expected Peak (in/hr):   0.20-0.40        0.30-0.60
Probability 0.50+ in/hr: 30%              65%
Probability 1.00+ in/hr: <5%              10%

Peak rates expected to occur between: 2200-0300

Chance of Thunderstorms: 20%
Isolated rates around 1.25 in/hr possible near thunderstorms.

&&                                    05-08  08-11  11-14  14-17  |  17-23  23-05

Los Angeles County...

WFKC1:West Fork Heliport               lgt    lgt    0.1    0.2   |   0.3   2.0
BDDC1:Big Dalton Dam                   lgt    lgt    lgt    0.1   |   0.1   1.0
PCDC1:Pacoima Dam                      lgt    lgt    lgt    0.2   |   0.1   1.1
FLTC1:La Canada Flintridge             lgt    lgt    lgt    lgt   |   0.2   1.2
SAUC1:Saugus                           0.0    lgt    lgt    lgt   |   lgt   0.9
CQT:Downtown LA                        lgt    lgt    lgt    lgt   |   lgt   0.8
MLUC1:Malibu Big Rock Mesa             0.0    lgt    lgt    lgt   |   0.1   0.9

1-Hr Rates:              Coasts/Valleys   Foothills/Mountains
Expected Peak (in/hr):   0.15-0.45        0.40-0.70
Probability 0.50+ in/hr: 45%              85%
Probability 1.00+ in/hr: <5%              25%

Peak rates expected to occur between: 0000-0400

Chance of Thunderstorms: 20%
Isolated rates around 1.5 in/hr possible near thunderstorms.

&&

DISCUSSION:

A cold and unstable air mass will spread over the area through
Thursday as a storm system moves over the region. This system with
well defined warm and cold fronts will bring 1 to 2 inches of rain
to the flatter portions of the csts/vlys and 2 to 4 inches over the
foothills and coastal slopes. Light rain will begin this morning
with system`s warm front, then rain will turn heavier as the cold
front moves over the region between this afternoon and Thursday
morning. Rainfall rates will likely excced a half inch per hour,
especially tonight into early Thursday when the cold front passes
through the area. The cold front will likely have enough instability
to generate isolated thunderstorms as well. A flood watch remains in
effect from this evening through Thursday afternoon.

In the mountains, 1 to 2 feet of snow could fall above 6500 feet.
Snow levels will fall to near 3000 feet Thursday afternoon and
travel on the major mountain passes may be adversly affected.

Another storm system will bring more rain and mountain snow Friday
into Friday night. Rain amounts will be under a half inch.

$$

Hall