Area Forecast Discussion
Issued by NWS San Diego, CA
FXUS66 KSGX 282053
Area Forecast Discussion
National Weather Service San Diego CA
153 PM PDT WED SEP 28 2016
A mid to upper level low will continue to move northward over the
area today, bringing variable mid and high clouds and the
potential for a few showers and thunderstorms, mostly in the
mountains. The low will move northeast of the local area Thursday
through Friday, followed by a longwave trough moving in from the
west this weekend into early next week. This will lead to gradual
cooling through the end of the week as onshore flow strengthens
and the marine layer slowly returns. It will turn much cooler by
the weekend with gusty westerly winds over the mountains and
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
Water vapor imagery shows a mid/upper level low centered near
Barstow this afternoon. This low will slowly drift north, with
just enough moisture present for the potential of a few showers or
even thunderstorms today, mainly over the mountains. Isolated shower
and thunderstorm activity has already begun and will remain focused
over the Riverside and San Bernardino County Mountains this
afternoon and evening, as the hi-res models continue to indicate.
Chances for showers making it into the inland valleys appear
slimmer now, as current cells are quickly dying as they drift off
the mountains into the much dryer air. The low will move
northeast of the area Thu-Fri, taking much of the moisture with
it. A slight chance of showers remains for a small portion of the
San Bernardino Mountains tomorrow, but dry everywhere by Friday.
Temperatures will continue on the warm side, but not to the level
of extreme heat seen this past weekend west of the mountains since
pressure gradients continue to trend onshore. More appreciable
cooling is expected this weekend into early next week as a
longwave trough amplifies along the West Coast, bringing afternoon
high temperatures back below average. Marine stratus will return
this weekend into early next week as well, extending further
inland each night as the marine layer deepens. Gusty onshore winds
will develop at times in the mountains and deserts, mainly during
the afternoons and evenings. Dry weather will prevail this weekend
through the first half of next week.
282000Z...Variable clouds above 10 kft with isolated SHRA/TSRA over
the mountains and foothills through 03Z. After 03Z...SCT100 through
No hazardous marine weather is expected through Friday. Northwest
winds will increase over the outer waters Saturday afternoon as a
trough deepens along the West Coast. The strongest winds will arrive
on Sunday and Monday when Small Craft Advisories may be needed over
the Outer Waters.
An building south swell tonight will bring elevated surf of 3-5 feet
Thursday and Friday. Sets to 6 feet are possible in Orange County.
The south swell decreases slightly over the weekend, but above
average surf of 2-5 ft will continue, highest in Orange County.
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.