Area Forecast Discussion
Issued by NWS San Diego, CA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS66 KSGX 312018
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
117 PM PDT MON AUG 31 2015

.SYNOPSIS...
A TROUGH OF LOW PRESSURE ALONG THE WEST COAST WILL BRING COOLING AND
A DEEPER MARINE LAYER THIS WEEK. NOCTURNAL MARINE CLOUDS AND FOG
WILL SETTLE A LITTLE FARTHER INTO THE VALLEYS EACH NIGHT THROUGH
WEDNESDAY MORNING...SLOWLY RETREATING AGAIN OVER THE UPCOMING
HOLIDAY WEEKEND AS THE TROUGH WEAKENS ALOFT. THIS ONSHORE PATTERN
WILL CONTINUE TO SUPPORT GUSTY LATE DAY AND OVERNIGHT WESTERLY WINDS
THROUGH THE PASSES AND ON THE DESERT SLOPES...AND NEAR TO SLIGHTLY
BELOW AVERAGE TEMPERATURES. ELEVATED SEA SURFACE TEMPERATURES WILL
MAKE FOR MILD NIGHTS ALONG THE COASTAL STRIP. A LITTLE WARMER FOR
THE LABOR DAY WEEKEND AND CONTINUED DRY.

&&

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

MARINE STRATUS CONTINUED TO SWIRL OVER THE CA BIGHT EARLY THIS
AFTERNOON ASSOCIATED WITH A WELL DEVELOPED EDDY CENTERED OVER SAN
CLEMENTE ISLAND. A FEW HIGH CLOUDS WERE SCATTERED OVER SAN DIEGO
COUNTY...OTHERWISE THE SKY OVER SOCAL WAS CLEAR. THE EDDY
DEVELOPMENT HAS DEEPENED THE MARINE LAYER AND LOWERED TEMPS SOME 5
TO 10 DEGREES F OVER VALUES OBSERVED MIDDAY YESTERDAY WEST OF THE
MTS. TEMPERATURES WERE UP TO 5 DEGREES F LOWER IN THE DESERTS. AT
NOON PDT...SURFACE PRESSURE GRADIENTS WERE WEAK ONSHORE TO NV...AND
AROUND 5 MBS ONSHORE TO THE LOWER DESERTS. WIND REPORTS WERE MOSTLY
LIGHT...EXCEPT LOCALLY THROUGH THE WIND-PRONE PASSES.

THE EDDY WILL WEAKEN OVER THE NEXT COUPLE OF DAYS...BUT THE MARINE
CLOUDS AND COOLER WEATHER WILL PERSIST...AS A LOW PRESSURE TROUGH
ALOFT GRADUALLY DEEPENS ALONG THE WEST COAST. THERE ARE SOME MODEL
DIFFERENCES WITH THE PLACEMENT AND DEPTH OF THE TROUGH...BUT
GENERALLY IT REACHES MAXIMUM AMPLITUDE OVER CA LATE IN THE WEEK...
THEN SLOWLY WEAKENS DURING THE LABOR DAY WEEKEND. COOLEST WEATHER
SHOULD BE THU/FRI TIME FRAME...FOLLOWED BY SLOW WARMING THROUGH
EARLY NEXT WEEK.

PRESENT INDICATIONS ARE THAT THE BENIGN WEATHER PATTERN ACROSS SOCAL
WILL HOLD TROUGH THE FIRST TEN DAYS OF SEPTEMBER. THE MODELS
INDICATE LITTLE LONGWAVE MOVEMENT OVER THE WESTERN HEMISPHERE...WITH
THE MASSIVE EASTPAC RIDGE ALONG 160W...AND THE RIDGING OVER CENTRAL
N.A. HOLDING. THESE ARE NO DOUBT HELPING TO ANCHOR THE WEAK TROUGH
ALONG THE WEST COAST...WHICH DEFLECTS ANY MONSOONAL FLOW FARTHER TO
THE EAST OF SOCAL...AND MAINTAINS ONSHORE FLOW AT THE SURFACE WITH
SEASONAL TEMPERATURES.

&&

.AVIATION... 312000Z...COAST/VALLEYS...MOSTLY CLEAR THROUGH EARLY
THIS EVENING. STRATUS...WITH BASES AROUND 1800 FT MSL AND TOPS NEAR
2500 FT MSL...WILL DEVELOP ALONG THE COAST LATE THIS EVENING. VIS OF
1-3 SM BR IS POSSIBLE WHERE LOW CLOUDS NEAR HIGHER INLAND TERRAIN
OVERNIGHT. LOW CLOUDS WILL CLEAR TOWARDS THE COAST AROUND 17Z TUE
MORNING.

MTNS/DESERTS...SKC WITH UNRESTRICTED VIS THROUGH TUE AFTERNOON.

&&

.MARINE... 100 PM...NO HAZARDOUS MARINE WEATHER IS EXPECTED THROUGH
FRIDAY.

&&

.BEACHES... 100 PM...AN ELEVATED SOUTHERLY SWELL WILL CREATE A HIGH
RISK OF RIP CURRENTS...AND SURF TO 6 FEET ALONG SOUTHERLY-FACING
BEACHES IN ORANGE COUNTY THROUGH THE MIDDLE OF THIS WEEK. A MODERATE
RISK OF RIP CURRENTS AND SLIGHTLY LOWER SURF IS FORECAST FOR SAN
DIEGO COUNTY BEACHES.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.
&&

$$

PUBLIC...JAD
AVIATION/MARINE...JJT


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.