Area Forecast Discussion
Issued by NWS San Diego, CA
FXUS66 KSGX 250346
Area Forecast Discussion
National Weather Service San Diego CA
846 PM PDT Mon Oct 24 2016
The low pressure system responsible for the scattered showers and
thunderstorms is moving east tonight. Fair and warmer through
Thursday as high pressure rebuilds over the Southwest. For Friday...
another low pressure trough will move inland, bringing cooler
weather, along with a chance for showers. Dry and mild next weekend
with the main storm track remaining across central and northern
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
After another very active day with hundreds of lightning strikes and
heavy downpours of rain, the weather is finally quieting down across
the CWA late this evening. At 8:20 PM PDT...radar still showed
intense echoes over the lower deserts moving rapidly NE. Water vapor
imagery showed the shortwave had passed and will take the high PW and
instability with it as winds aloft turn more westerly. The 00Z
Miramar sounding was indicating a SW wind shift above 3K FT, but
still had significant moisture between 5K and 13K FT. An MU Cape
value of 1350 J/K explains the explosive thunderstorm development!
Significant rains accumulated, especially over northern portions of
the CWA where a band of precipitation lingered and cells repeated
over the same area. Some larger rainfall totals in this area exceeded
1.5 inch in the mts. Showers and thunderstorms were more scattered
and a later show over southern Riverside and San Diego Counties where
total rainfall amounts were mostly under one-quarter inch. See
LAXRRMSGX for a complete list.
Quiet weather is shaping up for the next couple of days as high
pressure builds over NW Mexico and the SW U.S. Our surface flow will
remain onshore, so expect areas of marine clouds and fog nights and
mornings, otherwise fair and warmer a temperatures climb back through
the 80s inland each afternoon through Thu.
Farther west, a large trough will remain anchored offshore and spin
off another shortwave, arriving along the CA coast on Fri. The bulk
of the energy with this system will lift north through central and
northern CA, but it will bring us a chance of some showers, and we
may even get a few heavy ones as some subtropical moisture is
entrained into the system from the remnants of Tropical Cyclone
Seymour, but at this time the global models show light amounts here.
By the weekend, another stronger and colder system will spin east
toward the CA coast, but once again, much of the energy and moisture
is targeted to the north. At this time we expect some high clouds,
but little in the way of rainfall, and seasonal temps.
250330Z...Showers and thunderstorm activity should shift out of the
region by 06Z, with any impacts between now and then limited to the
deserts of Riverside and SD Counties. BKN-OVC bases in the 5,000 to
10,000 ft MSL range should slowly transition to FEW-SCT through 12Z.
A few patches of low clouds in the 1,500 to 2,000 ft MSL range are
possible along the coast through 18z Tuesday, but impacts are not
expected at the TAF sites. Fair skies and light westerly winds are
expected after 18Z Tuesday, with patchy low clouds returning to the
coast after 03Z Wednesday.
No hazardous weather conditions are expected through Thursday. A
storm system will affect the region Friday and Saturday, and this
period will have to be monitored for potential thunderstorm activity.
Skywarn activation is not requested at this time. However weather
spotters are encouraged to report significant weather conditions.