Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 281710
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
1000 AM PDT SAT MAR 28 2015

.SYNOPSIS...

HIGH PRESSURE ALOFT WILL WEAKEN AND DRIFT EAST THIS WEEKEND. A
SHALLOW MARINE LAYER WILL BRING COOLING TO THE COASTAL AREAS
TODAY...BUT IT WILL CONTINUE HOT IN THE VALLEYS AND DESERTS. DENSE
FOG IS LIKELY NEAR THE COAST AGAIN TONIGHT. SLIGHTLY COOLER IN ALL
AREAS SUNDAY WITH A WEAK TROUGH OVER SOUTHERN CALIFORNIA. NEXT WEEK
WILL CONTINUE TO BE WARMER THAN AVERAGE IN MOST AREAS. STORMS
PASSING BY TO THE NORTH WILL PRODUCE GUSTY WEST WINDS IN THE
MOUNTAINS AND DESERTS WEDNESDAY AND THURSDAY.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

A SHALLOW 400 FOOT DEEP MARINE LAYER CAPPED BY A STRONG INVERSION IS
PREVENTING THE LOW CLOUDS FROM MIXING OUT IN COASTAL ORANGE COUNTY
AND NORTHERN SAN DIEGO COUNTY THIS MORNING. BUT SURFACE HEATING
ALONG WITH MINOR COOLING ALOFT AHEAD OF THE TROUGH APPROACHING FROM
THE WEST SHOULD MIX OUT THE CLOUDS AT THE BEACHES THIS AFTERNOON.

THE MARINE LAYER WILL BRING A COOLER DAY TO THE COASTAL AREAS...BUT
IT WILL REMAIN HOT INLAND WITH VALLEY TEMPS IN THE MID 80S TO LOW
90S. RECORD HEAT IS LIKELY AT PALM SPRINGS AND THERMAL WHERE THE MAX
TEMPERATURE COULD REACH 100 FOR THE FIRST TIME THIS YEAR. THE RECORD
HIGH FOR BOTH STATIONS IS 97 WHICH WERE BOTH SET IN 1969.

THE MARINE LAYER DEPTH WILL NOT CHANGE MUCH TONIGHT...PERHAPS DEEPEN
A COUPLE HUNDRED FEET WITH THE UPPER TROUGH...SO AREAS OF DENSE FOG
ARE LIKELY IN THE COASTAL ZONES AND FAR WESTERN SAN DIEGO VALLEYS
TONIGHT INTO SUNDAY MORNING. THE TROUGH WILL BRING LOWER HEIGHTS...
SOME HIGH CLOUDS...AND STRONGER ONSHORE FLOW...ALL OF WHICH WILL
CONTRIBUTE TO A FEW DEGREES OF COOLING TOMORROW.

THE TROUGH PROGRESSION ACROSS THE SOUTHWEST HAS SLOWED AND IT NOW
LINGER THROUGH MONDAY BEFORE DRIFTING EAST MONDAY NIGHT. WEAK
RIDGING TUESDAY WILL BRING MINOR WARMING AND A BRIEF PERIOD OF WEAK
OFFSHORE FLOW. ON WEDNESDAY AND THURSDAY A STRONGER SHORTWAVE AND A
SOUTHERLY DIP IN THE JET STREAM INTO NORTHERN CALIFORNIA WILL BRING
FURTHER COOLING ALONG WITH STRONG WESTERLY WINDS TO THE MOUNTAINS
AND DESERTS.

THE LONG RANGE OUTLOOK FOR FRIDAY THROUGH NEXT WEEKEND...THE GFS
FORECASTS ZONAL FLOW FRIDAY TO TRANSITION INTO A DEEP WEST COAST
TROUGH SATURDAY AND SUNDAY EXTENDING ALL THE WAY DOWN INTO SOUTHERN
CALIFORNIA. THE ECMWF HAS A SIMILAR TROUGH PATTERN...BUT KEEPS THE
JET STREAM AND SHORTWAVE ENERGY FARTHER NORTH OVER NORTHERN AND
CENTRAL CALIFORNIA. THIS DEVELOPING PATTERN WILL BE SOMETHING TO
KEEP AN EYE ON IN THE COMING WEEK.

&&

.AVIATION...

281600Z...COASTAL AREAS...LOW CLOUDS AND FOG HAVE MOSTLY DISSIPATED
AND ERODED OFF THE COAST AT THIS TIME. MOSTLY SUNNY SKIES AND
UNRESTRICTED VIS WILL PREVAIL THROUGH THIS EVENING. AFT
29/00Z...PATCHY LOW CLOUDS AND FOG WILL REDEVELOP AT THE IMMEDIATE
COAST AND REMAIN VARIABLE/PATCHY IN COVERAGE THROUGH THE NIGHT.
PATCHY DENSE FOG IS A POSSIBILITY AGAIN TONIGHT...ESPECIALLY ON THE
COASTAL MESAS...INCL KCRQ. LOW CLOUDS AND FOG EXPECTED TO CLEAR OFF
THE COAST 29/15-17Z.

VALLEYS/MOUNTAINS/DESERTS...MOSTLY CLEAR WITH UNRESTRICTED VIS
THROUGH SUNDAY.

&&

.MARINE...

900 AM...PATCHY DENSE FOG POSSIBLE AGAIN TONIGHT THROUGH SUNDAY
MORNING...OTHERWISE NO HAZARDOUS MARINE WEATHER IS EXPECTED THROUGH
TUESDAY.

&&

.BEACHES...

900 AM...A SOUTH SWELL WITH A LONG PERIOD WILL CREATE STRONG RIP AND
LONGSHORE CURRENTS THIS WEEKEND...AS WELL AS ELEVATED SURF ALONG
SOUTH-FACING BEACHES. FOR DETAILS SEE THE BEACH HAZARDS
STATEMENT...LAXCFWSGX.

&&

.SKYWARN...
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...BEACH HAZARDS STATEMENT THROUGH SUNDAY AFTERNOON FOR ORANGE
     COUNTY COASTAL AREAS-SAN DIEGO COUNTY COASTAL AREAS.

PZ...NONE.
&&

$$

PUBLIC...MOEDE
AVIATION/MARINE...23



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