Area Forecast Discussion
Issued by NWS San Diego, CA
FXUS66 KSGX 291013
AREA FORECAST DISCUSSION
National Weather Service San Diego CA
313 AM PDT SUN MAY 29 2016
A weak low pressure system moving through Southern California
today will bring patchy morning drizzle for coastal areas...and a
slight chance of afternoon thunderstorms near the mountains. For
Monday through Thursday...high pressure aloft over California will
bring an inland warming trend and gradually shallower marine layer
with areas of night and morning coastal low clouds and patchy fog
not extending as far inland. Inland high temperatures will warm to
several degrees above average for Thursday and Friday. For next
weekend...another weak low pressure system may move inland through
Southern California bringing inland cooling...deepening of the
marine layer...and small chances for precipitation.
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
Water vapor imagery shows the center of a weak upper level low
pressure system moving into the Southern California bight. It will
move inland across Southern California today and Arizona Monday.
The marine layer has deepened to around 4000 feet with cloud bases
around 1500 to 2000 feet above mean sea level. From that 2000 to
2500 foot deep cloud layer there has been patchy drizzle since
Saturday evening with the most widespread light measurable amounts
across the coastal and valley areas of San Diego County. There
remains a slight chance of showers and thunderstorms this
afternoon...mainly near the mountains.
For Monday through Thursday...high pressure aloft over California
will bring an inland warming trend and gradually shallower marine
layer with night and morning coastal low clouds and patchy fog not
extending as far inland.
For next weekend...the global models bring a weak low pressure
system inland across Southern California. High temperatures that
will be several degrees above average for inland areas for
Thursday and Friday will begin to cool next weekend with a
shallower marine layer beginning to deepen. There are also small
chances for precipitation...mainly in the mountains during the
290930Z...Coast/Valleys...Low stratus clouds with bases 1200-2200 ft
above mean sea level and tops to 3000 ft MSL will continue to impact
coastal and valley locations and along the western slopes of the
inland mountains. Patchy drizzle will also continue this morning
near the coast and coastal slopes and mesas, through about 14z.
Stratus will slowly erode late this morning between about 17-20z and
some scatter out to the coast by 20-21z. With upper low proximity
and robust marine layer, expect to see the low stratus decks to
reform and push into the valleys after 02z this evening. Cloud bases
will again be similarly around 1200-2200 ft msl with tops to 3000-
4000 ft msl. Forecaster confidence is medium-high.
Mountains/Deserts...VFR conditions prevail through 18Z. With the
upper low in place and heating, isolated showers and thunderstorms
should pop up in the mountains and onto the high desert floor
between 18z this afternoon to 03z this evening. Forecaster
confidence is medium in isolated thunderstorm occurrence.
230 am...No hazardous marine conditions are expected
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.