Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Diego California
245 am PDT Thursday Sep 18 2014
a low pressure system approaching from the northwest will bring
cooler weather and lower humidities through the weekend. Stronger
onshore flow will bring gusty west winds to the mountains and
deserts this afternoon and evening. The marine layer will return
with coastal clouds extending locally inland nights and mornings.
Isolated thunderstorms may form over the mountains Saturday
afternoon. It will be dry and a little warmer early next week with
Discussion...for extreme southwestern California including Orange...
San Diego...western Riverside and southwestern San Bernardino
Skies were mostly clear this morning...but a deck of low clouds off
the coast was making a serious push into the California bight. Some
low clouds will form at the coast by sunrise...but the trend is
clear and unavoidable. The heat wave in the rear view mirror will
fade as we get back to normal in a hurry today. Low clouds will
probably make an early run at the coast this afternoon and early
evening. Also...the strengthening onshore flow will produce some
decent winds through mountain passes and into adjacent deserts this
afternoon and evening. It will feel like Spring. The big change
comes courtesy of a low pressure trough bearing down the West Coast.
On Friday this thing will cut off and circulate in our vicinity
through the weekend. The marine layer will respond by extending
coastal clouds into the entire coastal basin Friday morning. The
surge relaxes a bit over the weekend...but low clouds and fog will
still make it into some inland valleys. Temperatures will be around
average today and actually slightly below average Friday and
Saturday. The counter clockwise flow surrounding this low could draw
a wisp of moisture from Mexico on Saturday...leading to a slight
chance of mountain thunderstorms. The chance is very slight. The low
will slowly lift out of the region Sunday and Monday for some warmer
weather and less extensive coastal clouds nights and mornings early
next week. Extended models previously had a monster ridge forming
along the West Coast later next week...but recent runs are gaining
consistency in a trough solution around Wednesday or Thursday. That
would mean cooler weather and a stronger marine layer.
180930z...coast/valleys...patchy stratus with bases around 1200-1500
feet mean sea level will slowly develop along the coast this morning...possibly
reaching the coastal airports at times through 15z. Scattered to locally
broken stratus along the immediate coast this afternoon will begin to
push inland by 00z...spreading into the inland valleys overnight.
Bases will be around 1800-2200 feet mean sea level with tops to 2800 feet mean sea level.
Mountains/deserts...west winds with surface gusts 25-35 knots will develop
over the Desert Mountain slopes and adjacent desert foothills this
afternoon and evening. Otherwise mostly clear with unrestricted visible
through Friday morning.
245 am...local west-northwest winds with gusts to 20 knots are possible
over the outer coastal waters this afternoon. Otherwise...no
hazardous marine weather is expected through Monday.
245 am...a long period south-southwest swell will continue to
produce elevated surf and strong rip and longshore currents today.
Surf of 4 to 6 feet with locally higher sets likely on exposed
southwest facing beaches. Swell and surf will slowly lower Friday. A
beach hazards statement remains in effect through this evening.
Skywarn activation will not be needed today.
California...beach hazards statement through this evening for the
beaches in the Orange County coastal areas...San Diego County