Wildfire in California, August 31, 2022

Area Forecast Discussion
National Weather Service San Diego CA
134 PM PDT Wed Aug 31 2022

.SYNOPSIS...
A heat wave is expected to continue into early next week. The return
of some monsoonal moisture is expected to bring a slight chance of
thunderstorms mainly to the mountains Friday into next week. Skies
will be mostly clear, with a few high clouds and periods of patchy
low clouds near the coast.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

Forecast Highlights:
*A long duration heat wave will continue into early next week.
*High heat risk west of the mountains and in the High Desert,
 moderate heat risk in mountains and low deserts.
*Slight chance of isolated thunderstorms Friday into next week.

The heat wave is still on track to continue into next week. Coastal
temperatures are expected to be a few degrees cooler Thursday and
Friday with the development of a coastal eddy. With the eddy, low
cloud coverage is expected to increase Friday morning. A low level
moisture influx into the lower deserts will act to moderate
temperatures there Thursday and Friday. That being said, highs there
will be mostly above 108 degrees. Even with the slightly cooler
temperatures, highs will still be 5 to 10 degrees above average
across the forecast area.

Saturday through early next week the high pressure over the Great
Basin remains in place and is expected to strengthen for Saturday
and Sunday. High temperatures Saturday through Monday will be 15 to
20 degrees warmer than average for the coast and western valleys, 10
to 15 degrees above average for the Inland Empire and eastern
valleys in San Diego, 7 to 10 degrees above average in the
mountains, and 5 to 10 degrees above average in the deserts.
Excessive heat may continue into Tuesday, with gradual cooling
expected for the end of next week. In addition to the daytime heat,
nights will be quite warm as well with low temperatures for the
coast and valleys mostly in the 70s to around 80 with the warmer
lows near the coastal foothills. In the lower deserts, low
temperatures will mostly be in the mid 80s to lower 90s.

At the coast, the potential development of a coastal eddy late in
the weekend is adding some uncertainty to the high temperature
forecast. NBM guidance for coastal areas is showing an 8 degree
temperature spread between the cooler and warmer high temperature
solutions. That uncertainty in high temperatures continues into
Tuesday for coastal areas.

Mid level moisture and easterly flow could bring more afternoon
clouds to the mountains beginning on Thursday with small chances for
an isolated shower or thunderstorm in the higher mountains during
the afternoon and early evening. Slight chances of thunderstorms in
the mountains each afternoon and early evening, possibly drifting
into the adjacent inland valleys will continue into next week.

&&

.AVIATION...
312015Z...FEW-SCT cumulus with bases near 10,000 FT MSL over the
mtns this afternoon. FEW with bases near 1000 FT MSL will be
possible across the immediate coast after 04z Thu, though cigs are
not expected.

Otherwise...mostly clear through tonight.

&&

.MARINE...
Northwest winds occasionally gusting around 20 kt in the outer
waters this afternoon and evening. Otherwise, no hazardous marine
weather is expected through Monday.

&&

.FIRE WEATHER...
Hot conditions will continue into early next week. Friday into early
next week, mid-level moisture will return, bringing back a slight
chance of isolated afternoon thunderstorms to the mountains. Main
impact from storms will be the potential for gusty winds and dry
lightning. Some rainfall expected near thunderstorms but significant
accumulation and flooding is not expected. The hot and unstable air
mass over Southern California will raise mixing heights for inland
areas and increase the potential for large vertical plume growth
with any new fires that develop.

&&

.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Excessive Heat Warning until 8 PM PDT Monday for Apple and
     Lucerne Valleys-Coachella Valley-Orange County Coastal
     Areas-Orange County Inland Areas-Riverside County Mountains-
     San Bernardino County Mountains-San Bernardino and
     Riverside County Valleys-The Inland Empire-San Diego County
     Coastal Areas-San Diego County Deserts-San Diego County
     Mountains-San Diego County Valleys-San Gorgonio Pass Near
     Banning-Santa Ana Mountains and Foothills.

PZ...None.

&&

PUBLIC/FIRE WEATHER...CO
AVIATION/MARINE...Schenk