FXUS66 KSGX 221552
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
850 AM PDT TUE MAY 22 2012
.SYNOPSIS...
A DEVELOPING TROUGH OF LOW PRESSURE OVER THE WEST COAST WILL BRING 
STRONGER ONSHORE FLOW WITH A GRADUAL COOLING TREND AND SLOW 
DEEPENING OF THE MARINE LAYER FOR EXPANDING COASTAL LOW CLOUDS AND 
FOG THROUGH THURSDAY. AN UNSEASONABLY STRONG TROUGH OF LOW PRESSURE 
WILL CARVE ACROSS CALIFORNIA BRINGING SIGNIFICANT COOLING...A DEEP 
MARINE MARINE LAYER...AND STRONGER AND GUSTY WEST WINDS TO THE 
MOUNTAINS AND DESERTS. A SIGNIFICANT WARMING TREND WILL OCCUR FOR 
SUNDAY AND MONDAY AS HIGH PRESSURE OVER THE EASTERN PACIFIC EXPANDS 
INTO CALIFORNIA.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
.SHORT TERM (TODAY THROUGH WEDNESDAY NIGHT)...
THE MARINE LAYER HAS CHANGED LITTLE WITH BASES SLIGHTLY HIGHER. A 
BROAD UPPER TROUGH AND ELONGATED EXTENDED WESTERLY 140 KNOT PACIFIC 
JET IS CROSSING THE PACNW AND ACROSS IDAHO. THE AIR MASS DOES NOT 
CHANGE TODAY BUT COOLING BEGINS TONIGHT AND WEDNESDAY WHICH WILL 
START THE TREND TO A DEEPER MARINE LAYER AND COOLING OVER LAND. THE 
INITIAL WAVE PASSAGE TONIGHT WILL INCREASE LOW TO MID LEVEL FLOW 
ACROSS THE HIGH DESERTS AND INTO THE BANNING PASS ALONG I-10. THIS 
REGION WILL SEE A PEAK IN THE WINDS TONIGHT AND EARLY WEDNESDAY 
MORNING AND THEN DECREASE SIGNIFICANTLY. WILL CONSIDER WIND
ADVISORY TONIGHT AND EARLY WEDNESDAY FOR BANNING PASS AND PART
OF THE COACHELLA VALLEY.
&&
.LONG TERM (THURSDAY THROUGH MONDAY)...
THE MORE SIGNIFICANT CHANGES OCCUR ON THURSDAY OVER THE NORTH 
PACIFIC AS THE JET STREAM BUCKLES IN RESPONSE TO AN UPSTREAM JET 
CORE WHICH CARVES THE MEAN LONG WAVE TROUGH ACROSS THE EAST PACIFIC 
AND NORTHERN CALIFORNIA. THIS ENERGY ON THE BACKSIDE DEEPENS THE 
MEAN UPPER LEVEL TROUGH ALONG THE WEST COAST. THE MARINE LAYER WILL 
DEEPEN OVER 2000 FEET AND SPILL INTO THE INLAND EMPIRE ON THURSDAY 
BRINGING MUCH COOLER TEMPERATURES. THIS PATTERN WILL BRING A MUCH 
DEEPER SYSTEM INTO CENTRAL AND SOUTHERN CALIFORNIA ON FRIDAY AND 
FRIDAY NIGHT...RESULTING IN MUCH BELOW NORMAL TEMPERATURES INLAND. 
DESERT AND MOUNTAIN WINDS WILL BE MORE WIDESPREAD AND STRONG FROM 
FRIDAY THROUGH SATURDAY MORNING. WE SHOULD SEE WIDESPREAD DRIZZLE 
THURSDAY NIGHT AND THEN SCATTERED SHOWERS ON FRIDAY AS THE MARINE 
LAYER DEEPENS RAPIDLY TO OVER 5000 FEET ON FRIDAY. WILL LIKELY ADD 
SOME WEATHER FOR THIS. THE UPPER TROUGH AXIS IS THROUGH PER MODEL 
CONSENSUS ON FRIDAY...THOUGH THERE IS SOME SPREAD ON THE DEPTH OF 
THE TROUGH OR SOUTHERN LATITUDE EXTENT AS IT PASSES. THIS SHOULD 
RESULT IN CLEARING SPREADING FROM NORTH TO SOUTH ON SATURDAY AND 
MOSTLY CLEAR BY SUNDAY. WARMING DEVELOPS QUICKLY ON SUNDAY AND BACK 
TO A WARM AIR MASS FOR MONDAY MEMORIAL DAY WITH 18 TO 22C AT 850 MB 
OVER THE REGION AND LITTLE MARINE LAYER...POSSIBLE COMPLETE 
CLEARING. 
&&
.AVIATION...
221513Z...COAST/VALLEYS...OVC STRATUS ABOUT 10-20 SM INLAND THIS 
MORNING WITH BASES 500-900 FT MSL AND TOPS AROUND 1400 FT MSL WILL 
CLEAR TO THE IMMEDIATE COAST 1500-1700 UTC. 1700-23/0200 UTC...VFR 
CONDS PREVAILING WITH FEW-SCT CLDS AOA 18000 FT MSL THROUGH THE AREA 
AND SCT-BKN CLDS AT 1000 FT MSL LINGERING WITHIN 5 SM OF COAST. 
23/0200-0500 UTC...STRATUS MOVING INLAND ALONG SAN DIEGO...THEN 
REACHING ORANGE COUNTY 23/0500-0800 UTC. BY 23/1200 UTC...STRATUS 
WILL HAVE MOVED INLAND 15-25SM...WITH BASES 600 TO 1000 FT MSL AND 
TOPS 1500-2000 FT MSL. EXPECT AREAS OF VIS 3-6SM BR AND LOCAL VIS 
AOB 2SM OVER HIGHER COASTAL TERRAIN AND THROUGH CERTAIN VALLEYS. 
STRATUS SLOWLY CLEARING TO THE COAST 23/1600-1800 UTC.   
MTNS/DESERTS...VFR CONDS WITH FEW-SCT CLDS AOA 18000 FT MSL THROUGH 
WEDNESDAY AFTERNOON. WESTERLY WINDS WILL INCREASE TO 15 TO 25 KT 
LATE THIS AFTERNOON AND EVENING...WITH LOCAL GUSTS TO 40 KT THROUGH 
MTN PASSES/CANYONS AND ALONG DESERT SLOPES...RESULTING IN WK TO 
OCCASIONALLY MODERATE UDDFS AND LLWS OVER AND E OF MTNS. 
&&
.MARINE...
STRONG NORTHWEST WINDS...AT TIMES OVER 30 KNOTS...WILL PREVAIL IN 
THE WATERS NORTHWEST THROUGH SOUTHWEST OF POINT CONCEPTION TUESDAY 
THROUGH FRIDAY. THIS WILL BRING AN ELEVATED SHORT PERIOD NORTHWEST 
SWELL IN THE SAN DIEGO COUNTY OUTER COASTAL WATERS...MAINLY SOUTH 
AND WEST OF SAN CLEMENTE ISLAND. THESE SWELLS WILL PEAK WEDNESDAY 
THROUGH THURSDAY IN THE 7 TO 9 FOOT RANGE...POSSIBLY HIGHER AT 
TIMES. THE PERIOD WILL MOSTLY BE 10 SECONDS OR LESS. ALTHOUGH THE 
HIGHEST OF THE SWELL IS NOT EXPECTED TO REACH THE INNER WATERS...THE 
SOUTHWESTERN PORTIONS OF THESE WATERS COULD STILL BE SOMEWHAT CHOPPY 
WITH HEIGHTS NEAR 6 FEET AT TIMES AND PERIODS OF 10 SECONDS OR LESS. 
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.
&&
$$
PUBLIC...TARDY
AVIATION/MARINE...HARRISON