Scientific Forecaster Discussion
fxus66 ksgx 241136
Area forecast discussion
National Weather Service San Diego California
336 am PST Sat Feb 24 2018
dry and warmer through Sunday with weak offshore flow this
morning...onshore flow this afternoon and evening...and a little
stronger offshore flow for Sunday morning with gusty northeast
winds to around 35 mph near the coastal foothills and below passes
and canyons. A cold low pressure system from the north will bring
showers with lower snow levels for Monday night into Tuesday
evening along with a slight chance for thunderstorms on Tuesday.
Drier and a little warmer for Wednesday...then cool and breezy
with additional chances for showers for Thursday and Friday.
Discussion...for extreme southwestern California including Orange...
San Diego...western Riverside and southwestern San Bernardino
For this weekend...weak high pressure aloft will bring a daytime
warming trend with high temperatures warming to near average on
Sunday. The coldest temperatures for the weekend are expected
early this morning with overnight low temperatures slowly
moderating for tonight and Sunday night. Some low temperature
records could fall this morning...mainly in portions of the inland
Weak offshore flow this morning will bring some locally gusty
northeast winds below passes and canyons. The flow will go back
onshore for this afternoon and evening...then a little more
strongly offshore for Sunday morning with areas of northeast winds
with gusts to 35 mph near the coastal foothills and below passes
and canyons. Dry weather will continue into Monday. Onshore flow
will strengthen on Monday with cooling and with stronger and gusty
southwest to west winds in the mountains and deserts during the
afternoon and evening.
A cold low pressure system from the north will bring showers for
Monday night into Tuesday evening along with a slight chance for
thunderstorms on Tuesday. Rainfall will be somewhat variable given
the showery nature of the precipitation...but general rainfall
amounts are expected to range from one to two tenths of an inch
near the coast to one quarter to one half inch in the mountains
with locally greater amounts. Snow levels will lower to 2500 to
3000 feet early Tuesday...then fluctuate around 3500 feet for
Tuesday afternoon and evening. Snow levels could be low enough
late Monday night into Tuesday morning with snowfall in the upper
deserts from scattered snow showers. A few inches of snowfall is
possible in the mountains of San Bernardino and Riverside counties
with slightly greater totals possible in the San Diego County
For the middle to latter part of next week...a cold low pressure
system will gradually amplify across the eastern Pacific and
western states...then begin to move around next weekend with the
GFS on the faster end of the timing with the European model (ecmwf) and Canadian
models on the slower end with the timing.
Wednesday is expected to be drier and a little warmer. Then
cooler and breezy with increasing shower chances for Thursday and
Friday with showers possibly continuing into portions of next
241111z...sky clear and unrestricted visibility through Sunday morning.
Winds will fluctuate around through Sunday, but should remain light
at the taf sites. A period of moderate low level wind shear and/or up/downdrafts
possible along the desert slopes between 00z and 06z Sunday, will
transition to similar conditions below the Cajon Pass and along the
slopes of the Santa Ana Mountains between 10z and 16z Sunday.
no hazardous marine weather is forecast through the weekend. Winds
and seas will increase Monday into Tuesday as a storm system sweeps
through the socal bight. Expected northwest winds of 20 kts or
higher during this period.
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
California...frost advisory from midnight tonight to 8 am PST Sunday for San
Bernardino and Riverside County valleys-the inland Empire.
Freeze warning until 8 am PST this morning for San Bernardino
and Riverside County valleys-the inland Empire.
Frost advisory until 8 am PST this morning for San Diego County
valleys-San Gorgonio Pass near Banning.