National Weather Service Forecast Discussion
000
FXUS66 KSGX 182104
AFDSGX
Area Forecast Discussion
National Weather Service San Diego CA
204 PM PDT Mon Mar 18 2024
.SYNOPSIS...
Showers and thunderstorms are expected this afternoon and evening.
Thunderstorms are most likely in the valley and mountains but there
is a potential they could drift far enough west to impact coastal
areas. Slight chances of showers and isolated thunderstorms continue
into Tuesday but become more confined to the mountains and
foothills. Dry conditions are expected by Wednesday. Near to
slightly above normal temperatures are expected through Friday, with
a cooling trend into the weekend. Night and morning low clouds and
fog are expected along the coast for the middle to end of the work
week, with cloud coverage becoming more widespread into the weekend.
Breezier conditions over the mountains and deserts expected this
weekend, with the potential for precipitation.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
At 1 PM, the energy from the low pressure system currently over
eastern California had reached our forecast area. This has made for
an active afternoon with numerous showers and a few thunderstorms
in the mountains, valleys, and locally in the deserts. Storm
movement continues to be south and west, with showers and
thunderstorms expected to impact coastal areas through this
evening. The main impacts from thunderstorms will be gusty winds
and small hail. Winds at 850 and 700 mb are expected to stay
between 10-20 kt for the most part, which will keep the storms
moving and limit the flooding potential. Areas of slick roads
expected during the evening commute. Showers and thunderstorms
across the area are expected to diminish into this evening. In
addition to rain at lower elevations, periods of snow are expected
in the mountains above 7000 ft through Tuesday. Up to an inch of
snow is expected above 7000 ft.
There is good agreement that the low will push back to the east by
Tuesday, keeping the threat of any showers or thunderstorms more
confined the the mountains and mountain foothills. By Wednesday the
low should continue it`s journey east, allowing a weak ridge of high
pressure to build over central California. This will allow
temperatures for the middle to end of the work week to remain near
to slightly above average for this time of year. Marine layer night
and morning low clouds and fog are expected to return to the coast
by Wednesday and cloud coverage will spread further inland into the
end of the week as onshore flow increases.
A low pressure system is expected to move south and east from the
Gulf of Alaska into the US West Coast this weekend. Ensemble
solutions are in good agreement the incoming trough will begin to
influence our weather on Saturday. This means cooler, cloudier, and
potentially wetter conditions can be expected for the weekend into
early next week. An increase in westerly winds can also be expected
for at least the mountains and deserts. There is still some
uncertainty with the timing and placement of the trough between the
global models. Where the low goes will impact how much precipitation
Southern California will get and when. Current forecast for the
upcoming weekend closely follows NBM with periods of slight chances
of precipitation starting on Saturday and continuing into Monday.
&&
.AVIATION...
182055Z...ISO-SCT SHRA and TSRA moving southwest towards the coast.
Gusty outflow winds in excess of 30 kt, small hail, and reduced vis
in heavy rain possible in stronger TSRA. Otherwise variable mid/high
clouds at/above 6000 feet MSL after 04Z into Tuesday.
&&
.MARINE...
Showers and thunderstorms over the coastal waters late
this afternoon and evening, most likely near shore. Any
thunderstorm could produce gusty, erratic winds and lightning.
Otherwise, no hazardous marine weather is expected through Friday.
A Marine Weather Statement has been issued for lightning over the
coastal waters through 8 PM tonight.
&&
.BEACHES...
Scattered thunderstorms dropping lightning late this afternoon and
evening.
&&
.SKYWARN...
Skywarn activation is requested.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&
$$
PUBLIC...CO
AVIATION/MARINE/BEACHES...Small