FXUS66 KSGX 192041

Area Forecast Discussion
National Weather Service San Diego CA
141 PM PDT Fri Apr 19 2024

.SYNOPSIS... A mix of sun and clouds today will bring sunnier
conditions through the weekend with warmer weather as high pressure
settles into the area. Gusty winds will occur across parts of the
passes and deserts today through tonight as a shortwave passes
through. An area of low pressure off the coast will slowly come
ashore through next week, bringing cooling, windy, and potentially
wetter weather.



.SHORT TERM (Today through Monday)...
A weak shortwave passing over Southern California today has brought
slightly cooler weather with onshore flow over the area, where some
east-west passes are seeing wind gusts near 20-35 MPH.
Winds are expected to increase across these areas into the deserts
later this afternoon into tonight. Areas of the San Diego deserts
and San Gorgonio Pass are now under a Wind Advisory through tonight,
where winds may gust 45-65 MPH. These winds have helped to mix out
the inversion this morning across San Diego County with mostly sunny
skies, though a bit slower to clear across the LA Basin. Per latest
HREF guidance, chances for widespread low cloud cover west of the
mountains is high, impacting the area later this evening through
Saturday morning. Coastal areas should see better clearing this
weekend as the marine layer becomes shallower.

An area of high pressure will build in off the coast this week,
leading to warmer temperatures. Sunday will be the warmest day over
all with highs near 90 degrees across the Inland Empire and 100
degrees across the lower deserts. Probabilities for each of these
areas near San Bernardino and Palm Springs respectively have near
50-70% chance of seeing these temperatures.


.LONG TERM (Tuesday through Late Next Week)...
As the ridge breaks down by Tuesday, onshore flow will spread
cooling further inland. Areas west of the mountains will be a few
degrees cooler, while the deserts will hang onto one more warm
day in the 80s and 90s.

Long range models are becoming in better agreement of a cut off
low pressure system moving in off the Pacific starting Tuesday of
next week. This will bring a deepening marine layer with clouds
pushing further inland west of the mountains each night and
morning, along with cooler temperatures for all areas. Most areas
should see cooler than average temperatures by Wednesday and
Thursday. Winds will also increase. Depending on which day the low
nears SoCal, winds will be strongest. As of now, this is looking
like Thursday. Winds were increased in the forecast with
additional WRF guidance for Wednesday and Thursday to incorporate
uncertainty in the timing of the trough. Model ensembles show
potentially wet weather accompanied by this system as well. Timing
and amounts are still quite uncertain, but amounts look light
whatever does fall. Slight chance of showers was added to the
forecast along and west of the mountains starting Thursday
evening through Friday.


192035Z...Coast/Valleys...Clearing has occurred but patches of
low clouds continue, especially on the Orange County land and
water. Marine clouds expected to return on the coast by 03 UTC and
spread inland overnight as well as lower to 1500 to 2000 AGL. A
weak disturbance tracks through Socal near 00 UTC/20 which will
affect the marine layer and allow it to lower overnight. Light fog
developing for inland areas.

Otherwise...SCT cumulus at around 8000 feet over mountains
through 02Z and SCT high clouds at/above 20000 feet MSL with
unrestricted visibility into tonight. Surface wind increase to 20
knots sustained through 05 UTC for the Coachella Valley.


No hazardous marine conditions are expected through Tuesday.


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


CA...Wind Advisory until 3 AM PDT Saturday for San Diego County
     Deserts-San Gorgonio Pass Near Banning.





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