EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
AFDSAN 330 AM PDT WED APR 26 2000
...SYNOPSIS...
A WEAK COASTAL EDDY WILL BRING DENSE FOG TO THE BEACHES THIS
MORNING..OTHERWISE HIGH PRESSURE WILL BRING ONE MORE SUNNY AND WARM
DAY TO MOST OF SOUTHWEST CALIFORNIA. A TROUGH OF LOW PRESSURE MOVING
INLAND ALONG THE WEST COAST THURSDAY AND FRIDAY WILL BRING A DEEPER
MARINE LAYER TO SOUTHWEST CALIFORNIA WITH MORE EXTENSIVE NIGHT AND
MORNING LOW CLOUDS AND FOG...COOLER TEMPERATURES FOR ALL AREAS ...
AND BREEZY CONDITIONS FOR THE MOUNTAINS AND DESERTS. FAIR WITH A
WARMING TREND FOR THE WEEKEND.
...DISCUSSION...
FORECAST FM LAST NIGHT ON TRACK. THE BASE OF THE MARINE INVERSION
LOWERED TO BETWEEN 400 AND 600 FT AS SHOWN BY EARLY TUES EVENING
ACARS SOUNDINGS FM LAX/LGB/SNA/SAN...VERSUS 700 TO 800 FT MON
EVENING. WK CSTL EDDY EVIDENT IN SURFACE OBSERVATIONS AND WAS WELL
FORECAST BY THE ETA AND COAMPS. LATEST 00Z RUN OF THE COAMPS SHOWS
THE EDDY PERSISTING DURG THE DAY TODAY. THAT...IN COMBINATION WITH
THE WK SFC GRADIENTS AND STRONG SHALLOW MARINE INVERSION ARGUE FOR
PATCHY FOG LINGERING NR THE BEACHES TODAY. BOTH COAMPS AND ETA HAVE
A STRONGER AND WELL DEVELOPED CSTL EDDY TONIGHT THRU THU MORNING.
LOW CLOUDS/FOG SHOULD DEVELOP AND SPREAD MORE RAPIDLY INLAND THIS
EVENING. DEEPENING SHOULD BE SUFFICIENT FOR STRATUS TO REACH SAN
COUNTY VLYS AND POSSIBLY INLAND EMPIRE BY EARLY THU MORNING.
OTHERWISE...MAINLY MINOR TOUCH UPS TO THE CURRENT PACKAGE. INLAND FM
THE IMMEDIATE CST...TODAY SHOULD BE THE WARMEST DAY...WITH COOLING
FOR THU AND FRI...THEN SOME RECOVERY IN TEMPERATURES SAT XCP FOR THE
DESERTS. TRIMMED BACK OFSHR WORDING FOR CSTL AREAS IN THE EXTENDED
AS MDL TO MDL AND RUN TO RUN DIFFERENCES SUGGEST WK SYNOPTIC SUPPORT
AT BEST. LIKEWISE...WITH SURFACE HIGH PRESSURE CNTRD WELL TO THE N
OVR THE NRN ROCKIES AND WITH GENERAL CLIMATOLOGY FAVORING ONSHR FLOW
NR THE CST...ANY OFSHR WINDS ARE LIKELY TO BE WK...LOCALIZED...AND
NOT EXTEND TO THE CST.
SAN 000
.SAN...DENSE FOG ADV (SEE LAXNPWSAN).
MARTIN