EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
AFDSAN 930 PM PST MON MAR 25 2002
.SYNOPSIS...A SHALLOW MARINE LAYER WILL CAUSE PATCHY NIGHT AND MORNING
COASTAL LOW CLOUDS AND FOG. OTHERWISE...WEAK HIGH PRESSURE ALOFT WILL
KEEP THE WEATHER FAIR INTO WEDNESDAY EXCEPT FOR HIGH CLOUDS. UPPER LEVEL
LOW PRESSURE WILL BRING A CHANCE OF SLIGHT SHOWERS...MAINLY THURSDAY.
NEXT WEEKEND WILL BE FAIR AND WARMER UNDER HIGH PRESSURE.
.DISCUSSION...HIGH CLOUDS WERE EXTENSIVE THIS EVENING...AND THAT WAS
CONTRIBUTING TO SOME HIGHER EVENING TEMPS VERSUS 24 HOURS AGO.
ALSO...LOW CLOUDS WILL HAVE TROUBLE FORMING DUE TO THAT AND THE WEAK
PRESSURE GRADIENTS...THOUGH THE DEW POINTS ARE HIGH NEAR THE COAST...SO
WHEN THE HIGH CLOUDS THIN SLIGHTLY LATER TONIGHT...WE COULD HAVE PATCHY
LOW CLOUDS AND FOG DEVELOP NEAR THE COAST. ACARS SOUNDINGS SHOWED THAT
THE SURFACE TO 2500 FOOT LAYER WAS ALMOST ISOTHERMAL AT SAN...BUT UP AT
LAX...AN INVERSION HAD DEVELOPED AROUND 1000 FEET. EXPECT THE SAME
THING TO OCCUR DOWN HERE LATER TONIGHT.
THE WEAK RIDGING OF THE NEXT DAY OR SO WILL GIVE US BENIGN WEATHER AND
THE WARMING OF INLAND AREAS. THE NEXT WEATHER FEATURE WILL BE THAT
CLOSED LOW...PROGGED TO DROP SOUTH OVER THE COAST BUT MOST LIKELY TO
OUR SW AND INTO N BAJA. 00Z MSO SHOWS ZERO PRECIP FOR OUR AREA WED
NIGHT DESPITE A VORT MAX MOVING THROUGH...MOSTLY DUE TO INSUFFICIENT
RH...INCLUDING NEAR THE SURFACE. HOWEVER...A SMALL N OR NE CHANGE IN
THE TRACK WILL BRING PRECIP SOMETIME WED NIGHT THROUGH THU NIGHT...SO I
WILL NOT REMOVE THE POPS FROM THE FORECAST. THE WEEKEND LOOKS
HIGHER-CONFIDENCE AS BOTH ECM AND AVN HAVE RIDGING DEVELOPING FROM THE
WEST FOR PROBABLY ABOVE-NORMAL TEMPS AND RELATIVELY FEW CLOUDS.
.SAN...NONE.
MAXWELL