Area Forecast Discussion
Issued by NWS San Diego, CA

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FXUS66 KSGX 250937

Area Forecast Discussion
National Weather Service San Diego CA
237 AM PDT Thu May 25 2017

Cooler and cloudier weather is forecast from the mountains
westward through Friday as a weak trough of low pressure moves
through the region. Scattered light showers are expected tonight
and Friday morning. Strong winds will continue in parts of the
mountains and deserts through Friday. Higher pressure will push
down the marine layer and bring warmer weather this holiday
weekend. Fair and seasonal weather will continue next week.



The marine layer has deepened and has filled the entire coastal
basin with clouds right on schedule this morning. The cloud bases
are also rising so little if any fog and drizzle is expected.
Wave clouds to the southeast will gradually move on as the coastal
low clouds clear this morning. The low clouds may not completely
clear before increasing again late this afternoon. Winds in parts
of the mountains and deserts will continue pretty strong through
tonight, particularly east of San Gorgonio Pass and in the Anza
Borrego Desert. A low pressure trough will send a weak shortwave
right through Southern California tonight into Friday morning.
That will deepen the marine layer to at least 5000 feet and
provide enough lift to wring out some light showers from the coast
to the mountain slopes. It could make for a damp commute Friday
morning in some areas. Not much accumulation if any; highest
forecast amounts reach all of a tenth inch. It will be cool
Friday with highs almost entirely in the 60s in the coastal basin,
50s and 60s in the mountains, 70s in the high desert and around
90 in the lower desert (yes, that`s cool for them). As the trough
moves out replaced by higher pressure this weekend, seasonable and
reasonable weather returns with a well-behaved marine layer.
Holiday highs will be around 70 along the coast, mid 70s to lower
90s inland, 90s in the high desert and well over 100 in the lower
desert. After the holiday a very weak trough of low pressure
wobbles around the region for a while. That would deepen the
marine layer slightly and bring a gentle cooling trend. There
appears to be some increase in higher clouds from southern
latitudes as well.


250900Z...Coast/Valleys/Coastal Mountain Slopes...Stratus with bases
1500-2000 ft MSL will continue this morning and gradually lift to
2000-2500 ft by 16Z. Clearing expected to occur 16-19Z, though
coastal airports may remain BKN-OVC through much of the afternoon.
Clouds becoming BKN-OVC along/west of the mountains after 26/02Z
with bases near 2500 ft MSL and tops 4000-5000 ft MSL. Coastal
slopes of the mtns obscured in clouds/fog at times through Fri
morning. Isolated showers Friday 12Z-18Z.

Mountains/Deserts...Southwest to west winds with sfc gusts 35-45 kt
along the desert slopes/foothills and through the passes continuing
through Fri morning with MOD-STG UDDFS and pockets of LLWS over and
NE/E of the mountains.


No hazardous marine weather is expected through Monday.


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


CA...Wind Advisory until 8 AM PDT Friday for San Diego County Deserts-
     San Gorgonio Pass Near Banning.




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