AREA FORECAST DISCUSSION

 
 FXUS66 KSGX 132132
 AFDSGX
 
 AREA FORECAST DISCUSSION
 NATIONAL WEATHER SERVICE SAN DIEGO CA
 132 PM PST MON FEB 13 2012
 
 .SYNOPSIS...
 A PAIR OF COLD LOW PRESSURE SYSTEMS FROM THE NORTH WILL BRING 
 SHOWERS AND A SLIGHT CHANCE OF THUNDERSTORMS TODAY THROUGH EARLY 
 TUESDAY AND AGAIN WEDNESDAY THROUGH WEDNESDAY NIGHT. IN 
 ADDITION...THESE SYSTEMS WILL BRING SNOW TO HIGHER ELEVATIONS AND 
 GUSTY WEST WINDS OVER THE MOUNTAINS AND DESERTS. BUILDING HIGH 
 PRESSURE WILL BRING LOCALLY STRONG AND GUSTY NORTHEAST WINDS ALONG 
 WITH DRY AND WARMER WEATHER FOR THURSDAY AND FRIDAY. WEATHER WILL BE 
 A LITTLE COOLER FOR THE WEEKEND WITH ANOTHER CHANCE FOR 
 PRECIPITATION SUNDAY.
 
 &&
 
 .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
 SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
 COUNTIES...
 
 AN APPROACHING STORM SYSTEM CAN BE SEEN ON WATER VAPOR SATELLITE  
 DIGGING SOUTH OVER CENTRAL CALIFORNIA THIS AFTERNOON. THIS COLD 
 TROUGH WILL BRING SHOWERS AND THUNDERSTORMS THROUGH TONIGHT MAINLY 
 OVER AND WEST OF THE MOUNTAINS. WITH 500MB TEMPERATURES AS LOW AS 
 -28 DEG C...THUNDERSTORMS WILL BE POSSIBLE...WITH SOME CAPABLE OF 
 PRODUCING SMALL HAIL. RAINFALL AMOUNTS ARE EXPECTED TO RANGE FROM 
 ONE TENTH TO ONE QUARTER OF AN INCH NEAR THE COAST...TO ONE HALF TO 
 THREE QUARTERS OF AN INCH ON THE COASTAL MOUNTAIN SLOPES. AMOUNTS OF 
 ONE TENTH OF AN INCH OR LESS CAN BE EXPECTED IN THE DESERTS. IN 
 ADDITION...SNOW LEVELS LOOK TO FALL TO ABOUT 4000 FT BY LATE 
 TONIGHT...WITH SOME SNOW POSSIBLE DOWN TO 3500 FT IN THE HEAVIER 
 SHOWERS. A WINTER WEATHER ADVISORY IS IN EFFECT FOR THE HIGHER 
 ELEVATIONS...WITH 3 TO 6 INCHES OF SNOW POSSIBLE OVERNIGHT. 
 FINALLY...WINDS WILL BE RATHER STRONG AND GUSTY WITH THE PASSAGE OF 
 THIS SYSTEM. UPPER SUPPORT IS DECENT WITH THIS SYSTEM...WITH 70 TO 
 80 KT WESTERLY WINDS INDICATED AT 500MB. WINDS LOOK TO BE STRONGEST 
 OVER THE SAN DIEGO COUNTY...RIVERSIDE COUNTY AND SAN BERNARDINO 
 COUNTY MOUNTAINS AND DESERTS...WHERE A HIGH WIND WARNING IS IN 
 EFFECT. GUSTS TO 65 MPH ARE LIKELY IN THESE AREAS THIS AFTERNOON 
 THROUGH EARLY TUESDAY MORNING. WINDS WILL ALSO BE RATHER GUSTY OVER 
 COASTAL AREAS WHERE A WIND ADVISORY WILL GO INTO EFFECT THIS EVENING.
 
 SHOWERS WILL CLEAR OUT BY TUESDAY AFTERNOON AS A WEAK TRANSITORY 
 RIDGE MOVES IN...WITH BELOW NORMAL TEMPERATURES LINGERING. ON 
 WEDNESDAY...ANOTHER COLD UPPER TROUGH WILL MOVE THROUGH SOUTHERN 
 CALIFORNIA...ALTHOUGH MODELS INDICATE THIS SYSTEM BEING A LITTLE 
 MORE WEST THAN THE ONE FOR TODAY. THIS...IN ADDITION TO DEEPER 
 MOISTURE...MAY RESULT IN GREATER PRECIP AMOUNTS. ONCE AGAIN...SNOW 
 LEVELS WILL FALL TO 4000 FT OR SO AND SMALL HAIL WILL BE POSSIBLE IN 
 SOME THUNDERSTORMS. RIGHT NOW...TOTAL RAINFALL AND SNOWFALL AMOUNTS 
 FOR THIS SECOND STORM ARE SIMILAR TO THE ONE FOR TODAY...ALTHOUGH 
 THEY MAY TURN OUT TO BE MORE THAN WHAT WE ARE CURRENTLY INDICATING. 
 STRONG AND GUSTY WESTERLY WINDS OVER THE MOUNTAINS AND DESERTS ARE 
 ALSO LIKELY WITH THIS SYSTEM. 
 
 BY LATE THURSDAY MORNING...RIDGING BUILDS BACK IN WITH LOCALLY 
 STRONG AND GUSTY OFFSHORE FLOW...RESULTING IN DRY AND WARMER WEATHER 
 FOR THURSDAY AND FRIDAY. FLOW BECOMES MORE ZONAL ON SATURDAY WITH 
 TEMPERATURES LOWERING A LITTLE AND FAIR WEATHER CONTINUING.
 
 FOR SUNDAY...THE LATEST GFS RUN HAS COME MORE IN LINE WITH THE ECMWF 
 WITH THE COLD UPPER TROUGH STAYING TO THE NORTH AND EAST OF SOUTHERN 
 CALIFORNIA. UNTIL THE MODELS COME INTO BETTER AGREEMENT AND 
 RUN-TO-RUN CONSISTENCY...GONNA STICK WITH A SLIGHT CHANCE OF SHOWERS 
 FOR SUNDAY. 
 
 RIDGING BUILDS BACK IN BY MONDAY BRINGING PLEASANT WEATHER THROUGH 
 MID-WEEK. 
 
 &&
 
 .AVIATION...
 132055Z...WEAKENING COLD FRONT CURRENTLY ALONG A KNXP-KCRQ-KNUC LINE 
 STILL MOVING SE 30 KT...BY 0000 UTC ALONG A KIPL-MMES LINE. 
 AHEAD OF FRONT BKN-OVC MERGG LYRS BTWN 2000-10000 FT MSL AND AOA 
 20000 FT MSL...MTNS OBSCD...FRZLVL 8000 FT MSL...WINDS W 30-60KT IN 
 THE 5000-15000 FT LAYER CREATING STG-SVR UDDFS SFC WND GUSTS +50KT 
 THROUGH MTN GAPS WITH AREAS OF VSBY BLO 1SM BLSA OVER DESERTS.
 BEHIND FRONT AND THROUGH 13/1600 UTC...VSBY 4-6SM IN SCT SHRA/SHSN 
 SCT-BKN MERGG LYRS BTWN 2000-8000 FT MSL...FRZLVL 4000 FT MSL...MTNS 
 OBSCD...ISOLD TSTMS WITH TOPS TO 25000 FT MSL...WINDS NW 25-65KT IN 
 THE 5000-10000 FT MSL LAYER...STG-SVR UDDFS...SFC WND GUSTS +50KT 
 THROUGH MTN GAPS/OVER DESERT AREAS.
 
 &&
 
 .MARINE...
 WEAKENING COLD FRONT MOVING SOUTHEAST 30 KNOTS ACROSS INNER COASTAL 
 WATERS REMAINDER THIS AFTERNOON. EXPECT WINDS AND SEAS TO INCREASE 
 THIS EVENING THROUGH EARLY TUESDAY MORNING AS HIGH PRESSURE 
 REBUILDS. GALE WARNINGS AND HIGH SURF ADVISORIES GO INTO EFFECT AT 
 1600 PST. EXPECT FREQUENT WIND GUSTS 35-40KT AND COMBINED SEAS 10 
 FEET OR HIGHER. THERE IS A SLIGHT CHANCE OF THUNDERSTORMS OVER THE 
 COASTAL WATERS THIS EVENING THROUGH TUESDAY MORNING AS THE COLD CORE 
 OF THE UPPER LOW PRESSURE SYSTEM MOVES BY.
 
 &&
 
 .SGX WATCHES/WARNINGS/ADVISORIES...
 CA...HIGH WIND WARNING UNTIL 3 AM PST TUESDAY FOR THE COACHELLA      
      VALLEY...RIVERSIDE COUNTY MOUNTAINS...SAN DIEGO COUNTY          
      DESERTS...SAN DIEGO COUNTY MOUNTAINS.
 
      WINTER WEATHER ADVISORY UNTIL MIDNIGHT PST TONIGHT ABOVE 5000 
      FEET FOR THE RIVERSIDE COUNTY MOUNTAINS.
 
      HIGH SURF ADVISORY FROM 4 PM THIS AFTERNOON TO 10 AM PST TUESDAY 
      FOR THE BEACHES IN THE ORANGE COUNTY COASTAL AREAS...SAN 
      DIEGO COUNTY COASTAL AREAS.
 
      WIND ADVISORY FROM 6 PM TO 10 PM PST THIS EVENING FOR THE ORANGE 
      COUNTY COASTAL AREAS...SAN DIEGO COUNTY COASTAL AREAS.
 
      HIGH WIND WARNING UNTIL 3 AM PST TUESDAY FOR THE APPLE AND 
      LUCERNE VALLEYS...SAN BERNARDINO COUNTY MOUNTAINS.
 
      WINTER WEATHER ADVISORY UNTIL 10 PM PST THIS EVENING ABOVE 5000 
      FEET FOR THE SAN BERNARDINO COUNTY MOUNTAINS.
 
      WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 8 AM PST 
      TUESDAY ABOVE 5000 FEET FOR THE SAN DIEGO COUNTY MOUNTAINS.
 
 PZ...GALE WARNING FROM 4 PM THIS AFTERNOON TO 10 AM PST TUESDAY FOR 
      THE COASTAL WATERS FROM SAN MATEO POINT TO THE MEXICAN 
      BORDER AND OUT 30 NM...WATERS FROM SAN MATEO POINT TO THE 
      MEXICAN BORDER EXTENDING 30 TO 60 NM OUT INCLUDING SAN 
      CLEMENTE ISLAND.
 
 
 &&
 
 

 
 PUBLIC...HARRISON/PG
 AVIATION/MARINE...BALFOUR
 
 
 
 
 
 
 

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