EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
AFDSAN 230 AM PDT WED APR 10 2002
.SYNOPSIS...SOME WARMING ALOFT AND A SLIGHTLY MORE SHALLOW MARINE
LAYER WILL BRING A WARMER DAY TODAY...ESPECIALLY INLAND. A WEAK
TROUGH OF LOW PRESSURE WILL MOVE BY TO THE NORTH FRIDAY AND SATURDAY
TO BRING A SLIGHT COOLING TREND AND MORE NIGHT AND MORNING LOW
CLOUDS. OTHERWISE...THE STORM TRACK WILL STAY WELL TO THE NORTH...SO
NO PRECIPITATION IS EXPECTED THROUGH EARLY NEXT WEEK.
.DISCUSSION...LOW CLOUDS COVER COASTAL SAN DIEGO COUNTY...BUT THEY
ARE SOMEWHAT PATCHY OVER THE SAN DIEGO COUNTY VALLEYS AND UP NORTH.
WEAK OFFSHORE TRENDS...WARMING ALOFT AND A LACK OF AN EDDY HELPED TO
BRING THE INVERSION TO A LOWER ELEVATION...NOW AROUND 1300 FEET
BASED ON OBS AND ACARS SOUNDINGS. SO...LOCALLY DENSE FOG WILL OCCUR
IN THE VALLEYS...BUT FOR NOW...THE MESAS LOOK SAFE. TEMPS SHOULD
INCREASE A FEW DEGREES FROM THE READINGS SEEN TUESDAY...WITH THE
DESERTS RESPONDING THE MOST FROM THE TEMP INCREASES ALOFT.
BOTH THE 4-KM RES WORKSTATION-ETA AND 12-KM RES MSO HAVE AN EDDY FOR
THU AM...AND MSO HAS IT BEING A BIT STRONGER FRI AM. THUS...WE
SHOULD SEE A GRADUAL INCREASE IN THE MARINE LAYER DEPTH AGAIN THEN.
THE WEAK TROUGH APPROACHING FROM THE NW WILL AID THE EDDY...BUT
OVERALL...ITS EFFECT WILL NOT BE TOO SIGNIFICANT. HIGH CLOUDS WILL
DRIFT OVER FROM TIME-TO-TIME WITH SOME MOISTURE IN THE ZONAL
FLOW...AND WITH THE TROUGH AND ONSHORE FLOW...THE WINDS WILL
INCREASE IN THE UPPER DESERTS. OVER THE WEEKEND INTO EARLY NEXT
WEEK...A LONG-WAVE TROUGH WILL COVER THE W US...SO WE WILL BE UNDER
NW FLOW BUT WITH MODERATE HEIGHTS. NEVERTHELESS...MTNS/DESERTS WILL
COOL ABOUT 5 DEGREES THEN...BUT WITHOUT ANY BIG AIRMASS CHANGE...THE
MARINE LAYER LOW CLOUDS AND FOG WILL CONTINUE WITH MINOR DAY-TO-DAY
VARIATIONS.
.SAN...NONE.
MAXWELL