EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
AFDSAN 850 AM PST SAT MAR 17 2001
...SYNOPSIS...
BUILDING HIGH PRESSURE ALOFT WILL BRING A WARMING TREND ALONG WITH
MOSTLY CLEAR SKIES TODAY AND SUNDAY. WARM WEATHER SHOULD CONTINUE
THROUGH MOST OF THE WEEK...EXCEPT NEAR THE IMMEDIATE COAST WHERE IT
WILL BE COOLER DUE TO THE COLD OCEAN WATER. THE SPRING EQUINOX
OCCURS ON TUESDAY AT 531 AM...PACIFIC STANDARD TIME.
...DISCUSSION...
THE PASS/CANYON WINDS WERE MINIMAL THIS MORNING. AROUND
SUNRISE...THE ACARS OUT OF ONTARIO WERE SHOWING EAST WINDS AT AROUND
5 MPH THROUGHOUT MOST OF THE LOWEST 5000 FEET...SO IT WAS OBVIOUS
THAT ANY POST-SUNRISE WINDS...ONCE THE INVERSION MIXED OUT...WOULD
NOT HAPPEN. THERE WAS SOME COLD AIR ADVECTION...BUT EVEN THAT IS
DECREASING. SURFACE GRADIENTS WERE MINIMAL OFFSHORE TO THE
NORTH...AND ONSHORE TO THE EAST. EVEN DAGGETT HAD A WEST WIND OF
AROUND 10 KNOTS MOST OF THE NIGHT. A FEW LOW CLOUDS CURRENTLY
REMAIN IN WESTERN SAN DIEGO AND OVER SOME BEACHES OF ORANGE COUNTY.
850 MB TEMPS INCREASE QUITE A BIT THROUGH SUNDAY...THEN INCREASE
SLIGHTLY THROUGH TUESDAY. TEMPS AT THAT LEVEL COULD REACH 20 DEG C
BY TUESDAY...WHICH MEANS SURFACE TEMPS COULD BE AS HIGH AS AROUND 95
IN THE DESERTS FOR THE FIRST TIME THIS YEAR.
WHILE LOW CLOUDS SHOULD STAY JUST TO OUR SOUTH TONIGHT...SINCE IT
LOOKS UNLIKELY THAT AN EDDY WOULD FORM AND LOW-LEVEL WINDS WILL BE
NORTHERLY ENOUGH...THE SEA BREEZE SUNDAY SHOULD REINFORCE AT LEAST
SOME MARINE LAYER. THUS...AT LEAST PATCHY LOW CLOUDS AND FOG SHOULD
BE EXPECTED STARTING SUNDAY NIGHT NEAR THE COAST.
IN THE EXTENDED...IT LOOKS FAIR UNTIL AT LEAST THU...THEN
POSSIBLY A TROUGH OF SOME SORT COULD MOVE IN. ECM HAS A LARGE CLOSED
LOW AROUND 140W FRI...AND IF THAT IS STATIONARY...THEN OUR FAIR
WEATHER COULD BE EXTENDED INTO FRI/SAT. MRF HAS A NEGATIVELY-TILTED
TROUGH WHICH COULD BRING PRECIP AS EARLY AS FRIDAY...AND NOGAPS HAS
A WEAKER SYSTEM WITH SIMILAR TIMING TO THE MRF...WHICH MIGHT
INDICATE JUST A SIGNIFICANT MARINE LAYER. THE CANADIAN...AVAILABLE
THROUGH 00Z THU...INDICATES MORE OF AN OPEN TROUGH LIKE THE MRF THAN
THE CLOSED LOW OF THE ECM. 12Z NOGAPS WILL BE VIEWED WHEN
AVAILABLE...BUT THE EXTENDED THIS AFTERNOON WILL MOST LIKELY HAVE
COOLING LATE IN THE WEEK AND POSSIBLY A CHANCE OF SHOWERS FRI/SAT.
A ZONE UPDATE WAS ISSUED AT 730 AM.
SAN 000
.SAN...NONE.
MAXWELL