000
FXUS66 KSGX 161025
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
325 AM PDT THU MAY 16 2013

.SYNOPSIS...
A LOW PRESSURE TROUGH DEEPENING OVER THE WEST COAST WILL BRING
COOLING THROUGH FRIDAY ALONG WITH GUSTY WINDS IN THE MOUNTAINS AND
DESERTS. A DEEPENING MARINE LAYER WILL SPREAD FARTHER INTO THE
VALLEYS EACH NIGHT...REACHING THE LOWER COASTAL SLOPES OF THE
MOUNTAINS FRIDAY AND SATURDAY MORNINGS. LIGHT RAIN OR DRIZZLE IS
POSSIBLE WEST OF THE MOUNTAINS ON FRIDAY FROM THE DEEP MARINE LAYER.
OVER THE WEEKEND...BUILDING HIGH PRESSURE WILL BRING DRYING AND
WARMING WITH A SHALLOWER MARINE LAYER.

&&

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

A COASTAL EDDY WAS SPINNING IN BIGHT EARLY THIS MORNING HELPING TO
LIFT MARINE CLOUDS INLAND THROUGH THE WESTERN VALLEYS. ONSHORE SFC
PRESSURE GRADIENTS WERE SUPPORTING LOCAL WIND GUSTS OF 20 TO 35 MPH
WITH ISOLATED HIGHER GUSTS AT TIMES THROUGH THE BANNING PASS AND
NEAR THE DESERT SLOPES. GRADIENTS WERE SLOWLY DECREASING AND THE
WINDS WILL FOLLOW THROUGH THE MORNING. SKIES WERE CLEAR ABOVE THE
MARINE LAYER BUT SMOKE WAS REPORTED ACROSS THE HIGH DESERT FROM THE
GRAND FIRE NEAR THE KERN/VENTURA COUNTY BORDER.

WESTERLY FLOW ALOFT WILL TURN MORE SW TODAY AND TONIGHT AS A LOW
PRESSURE TROUGH DIGS SOUTH OVER CA. THE FALLING HEIGHTS AND
CONTINUED COASTAL EDDY WILL CONTINUE TO DEEPEN THE MARINE LAYER INTO
FRI MORNING. SOME LIGHT SHOWERS OR DRIZZLE WILL BE POSSIBLE TONIGHT
AND AGAIN ON FRI NIGHT W OF THE MOUNTAINS...AND THE COOLING TREND
WILL CONTINUE INLAND. HEIGHTS/THICKNESS WILL RISE RAPIDLY OVER THE
WEEKEND AS THE TROUGH SLIPS EAST AND HIGH PRESSURE OVER THE EASTPAC
EXPANDS OVER SOCAL. WARMING WILL PEAK AROUND MON...FOLLOWED BY
INCREASING ONSHORE FLOW AND COOLING AS A LARGE AREA OF LOW PRESSURE
EXPANDS SOUTHWARD ALONG THE WEST COAST NEXT WEEK.

COASTAL AREAS...A COASTAL EDDY CIRCULATION SHOULD PERSIST INTO THE
WEEKEND. STRATUS LAYER SHOULD BURN BACK TO THE COAST THU MORNING...
BUT A DEEPENING MARINE LAYER ON FRI MAY LEAK SOME DRIZZLE OR LIGHT
RAIN SHOWERS WITH LIMITED CLEARING. MORE SUN EXPECTED OVER THE
WEEKEND AND SLIGHTLY WARMER. OTHERWISE DAYTIME TEMPS WILL BE NEAR
MID MAY NORMALS.

INLAND VALLEYS AND FOOTHILLS...STRATUS LAYER AND AREAS OF FOG
BURNING OFF QUICKLY THIS MORNING AND COOLER. CONTINUED COOLING INTO
FRI WITH MORE PERSISTENT CLOUDINESS AND A CHANCE OF DRIZZLE OR A FEW
LIGHT SHOWERS AT TIMES. MOSTLY SUNNY OVER THE WEEKEND WITH A WARMING
TREND PUSHING DAYTIME TEMPS BACK TO SLIGHTLY ABOVE AVERAGE BY SUN.

MTNS/DESERTS...SOME ISSUES WITH SMOKE MAY LINGER OVER THE HIGH
DESERT...ESPECIALLY NEAR THE MTN SLOPES...BUT EXPECT BETTER MIXING
THROUGH THE MORNING WILL HELP. OTHERWISE FAIR THU/FRI AND BREEZY TO
LOCALLY WINDY LATE AFTERNOON AND OVERNIGHT. STRONGEST WESTERLY WINDS
EXPECTED ON FRI EVENING WHEN A WIND ADVISORY MAY BE NEEDED.


&&

.AVIATION...
160900Z...LOW CLOUDS WILL EVENTUALLY FILL MOST OF THE COASTAL BASIN
BY SUNRISE. BASES WILL BE 1600-2000 FEET ASL. CLOUDS WILL CLEAR FROM
COASTAL AIRPORTS AROUND 17-18Z THIS MORNING. AREAS OF SMOKE COULD
REDUCE VIS IN LOCALIZED POCKETS AROUND THE SAN BERNARDINO MOUNTAINS
AND HIGH DESERT THIS MORNING. LOW CLOUDS WILL LIKELY RETURN TO
COASTAL AIRPORTS AROUND 00-05Z THIS EVENING AND INTO KONT BY 08Z.
SOME HIGHER CLOUD LAYERS ABOVE 10000 FEET ASL WILL ALSO BEGIN TO
THICKEN OVERNIGHT.

&&

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

PZ...NONE

&&

$$

PUBLIC...JAD
AVIATION/MARINE...MM