EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
AFDSAN 330 AM PDT WED APR 12 2000
...SYNOPSIS...
ONE MORE WARM DAY FOR MOST OF SOUTHWEST CALIFORNIA BEFORE AN UPPER
LEVEL LOW PRESSURE SYSTEM MOVES ONSHORE INTO CALIFORNIA THURSDAY AND
FRIDAY BRINGING COOLER WEATHER TO SOUTHWEST CALIFORNIA...BREEZY
CONDITIONS FOR THE MOUNTAINS AND DESERTS...MORE EXTENSIVE COASTAL
LOW CLOUDS...AND A CHANCE OF LIGHT SHOWERS.
...DISCUSSION...
A STRONG...SHALLOW MARINE INVERSION CONTINUES ALG THE SRN CA CST
WITH EARLY TUE EVENING ACARS SOUNDINGS AND NKX RAOB SHOWING THE BASE
OF THE INVERSION AROUND 600 FT LAX/LGB/SNA TO 1000 FT NKX. SATELLITE
IMAGERY SHOWS AN EXTENSIVE STRATUS FIELD OFF THE CST EXTENDING A FEW
MILES INLAND ALG THE ORANGE COUNTY CST AND LCLLY INLAND ALG THE SAN
COUNTY CST. DENSE FOG ADV HAS BEEN ISSUED FOR THE CSTS OF ORANGE AND
SAN COUNTIES (ZONES 42 AND 43) UNTIL 9 AM TODAY.
HEIGHTS AND THICKNESSES OVR SW CA INCR SLIGHTLY TODAY...THEN DECR
SIGNIFICANTLY THU AND FRI AS THE UPR LOW OVR THE ERN PAC MOVES
SLOWLY ONSHR INTO CA. VERY WK ONSHR LOW LVL FLOW GRADUALLY
STRENGTHENS THE NEXT TWO DAYS BECOMING MDT ONSHR THU NIGHT AND FRI.
INLAND HIGHS SHOULD CHANGE LTL TODAY FM TUE LVLS...THEN COOL FOR ALL
AREAS THU AND FRI. AVN INCR IN LOW LVL MSTR AND MDT MID LVL DYNAMICS
WOULD SUPPORT CHANCE OF LIGHT RAIN OR SHOWERS OVR MOST OF SW CA LATE
THU NIGHT INTO FRI MORNING. FOR NOW...HAVE ADDED CHANCE POPS WORDING
TO NW HALF OF FORECAST AREA FOR LATE THU NIGHT THRU FRI MORNING.
AFTER SIGNIFICANT COOLING FOR THU AND FRI...SOME RECOVERY IN
TEMPERATURES OCCURS FOR SAT AND SUN IN ADVANCE OF A POSSIBLY MORE
SIGNIFICANT TROUGH FOR LATE SUNDAY NIGHT INTO EARLY NEXT WEEK.
SAN 001
.SAN...DENSE FOG ADV (SEE LAXNPWSAN).
MARTIN