Area Forecast Discussion
Issued by NWS San Diego, CA

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FXUS66 KSGX 201623

Area Forecast Discussion
National Weather Service San Diego CA
923 AM PDT Sat Apr 20 2024

Warming this weekend with less night and morning marine layer clouds
as a ridge of high pressure moves over the area. A low pressure
trough deepening down the coast will come ashore next week, bringing
gradual cooling and stronger onshore winds. There is a slight chance
of showers in the latter half of the week when the trough progresses



.Morning Update...
Extensive low cloud coverage west of the mountains this morning is
seen on GOES imagery. The forecast was updated to prolong these
low clouds a bit longer into the afternoon, especially for areas
across the LA Basin, which look quite socked in with cloudy
conditions. Weak high pressure overhead will shrink the marine
layer, keeping these low clouds closer to the coast by Sunday and
Monday mornings. The warmest temperatures over the next week will
occur by Sunday and Monday with above average readings for many.

We will continue to watch the next weather system that will move
in off the coast next week. Breezy conditions with cooler weather
are likely, but confidence on precipitation occurrence and timing
is still low. Stay tuned for the latest updates.

.Previous Discussion (335 AM Today)...
Marine layer clouds that cover the Inland Empire and all of
Orange and San Diego Counties this morning will retreat back to
the coast through midday, but skies may not fully clear at the
beaches. Weak high pressure building over the Southwest this
weekend will squash the marine layer a few hundred feet, and the
night and morning clouds will not extend as far inland tonight and
Sunday night.

The ridge will bring warming this weekend, the exception near the
coast where highs will be in the 60s both days. A few miles inland
from the coast the highs will be in the 60s and low 70s. Farther
inland it will be much warmer with highs near 80 in the Inland
Empire, the 60s and 70s in the mountains, and the mid to upper 90s
in the lower deserts. Sunday will be the warmest day with highs from
85-90 in the Inland Empire and the high deserts, near 100 in the
lower deserts, but cooler 60s to mid 70s in the coastal zones.

The ridge drifts east Monday and Tuesday and an eastern Pacific
trough deepening down the West Coast will bring increasing onshore
flow, a deeper marine layer, cooler weather and gusty onshore winds
Wednesday and Thursday. This trough will bring a chance for light
rain or drizzle west of the mountains in the steadily deepening
marine layer ahead of the trough, and a chance for post frontal
showers Friday and Saturday as the cold core low tracks across
Southern California. Highs both days will be 5-10 degrees below
average Friday and Saturday with coastal and valley highs in the
60s, mountain highs in the 40s and 50s, high desert highs in the 60s
and low desert highs near 80.


201030Z...Coast/Valleys...BKN/OVC low clouds 1200-2500 ft MSL
will slowly scatter out in areas of San Diego County this morning,
but will be slower to scatter for areas northward, mostly like
after 19Z across OC. Confidence on clearing times for northern
areas is low, but improvements in vis across the IE are more
certain by later this morning. Stratus will develop again near the
coast 01Z-04Z Sun, spreading up to 25 miles inland 07-09Z Sun.
Lower bases near 1000-1800 ft MSL expected. Higher terrain will be
obscured with areas of VIS 1-5 miles in the valleys. Clouds
clearing a bit faster on Sunday morning, mainly after 17Z.

Mountains/Deserts...Mostly clear skies with unrestricted VIS will
prevail through Sun morning.


No hazardous marine conditions are expected through Wednesday.


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





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