Area Forecast Discussion
Issued by NWS San Diego, CA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
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 192145
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
145 PM PST FRI DEC 19 2014

.SYNOPSIS...
THE TAIL END OF A WEAKENING COLD FRONT WILL MOVE ACROSS SOUTHERN
CALIFORNIA TONIGHT...INCREASING CLOUDS THIS EVENING AND BRINGING
SOME ISOLATED SPRINKLES OR MOUNTAIN FLURRIES TO THE AREA TONIGHT
INTO SATURDAY MORNING.  HIGH PRESSURE WILL THEN REBUILD ALONG THE
WEST COAST BY SUNDAY...WITH DRY AND WARMER CONDITIONS DEVELOPING
THROUGH EARLY NEXT WEEK.  OFFSHORE FLOW WILL DEVELOP AS WELL THESE
DAYS.  HOWEVER...COOLER CONDITIONS AND ONSHORE FLOW WILL RETURN FOR
THE LATTER PART OF THE WEEK AND THE HOLIDAY WEEKEND.

&&

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

WATER VAPOR IMAGERY CONTINUES TO SHOW A NEGATIVELY TILTED TROUGH OF
LOW PRESSURE MOVING INLAND ACROSS THE PACIFIC NORTHWEST AND NORTHERN
CALIFORNIA THIS AFTERNOON.  HIGH CLOUDS ASSOCIATED WITH THIS SYSTEM
ARE BEGINNING TO SPREAD ACROSS SOUTHERN CALIFORNIA...BUT FOR THE
MOST PART...IT IS A BEAUTIFUL DAY OUT THERE.  IN FACT...TEMPERATURES
ARE RUNNING UP TO 4 DEGREES WARMER MOST PLACES.  WITH THIS
INCREASING CLOUD COVER AND THE WARMER TEMPERATURES TODAY...OVERNIGHT
TEMPERATURES SHOULD NOT DROP QUITE AS MUCH AS THE DID LAST
NIGHT...BUT A FEW LOCATIONS WILL STILL BE ON THE CHILLY SIDE
TOMORROW MORNING.  THE ONLY OTHER CONCERN FOR TONIGHT CONTINUES TO
BE WITH THE THREAT OF SOME SPRINKLES.  AT THIS TIME...ALL BUT ONE OF
THE 12Z MODELS BACKED OFF THE POSSIBILITY OF ANY PRECIPITATION
MAKING SOUTH OF POINT CONCEPTION.  FOR THIS REASON...THINK THAT ANY
REAL SHOWERS WILL BE UNLIKELY...BUT GIVEN THE 1 INCH PW PLUME OUT
THERE...THINK THAT A FEW SPRINKLES OR MOUNTAIN FLURRIES CANNOT
COMPLETELY BE RULED OUT EITHER.

HIGH PRESSURE PRESSURE WILL REBUILD ALONG THE WEST COAST FOR SUNDAY
AND THE FIRST PART OF THE WORK WEEK...WITH DRY AND WARMER CONDITIONS
DEVELOPING.  OFFSHORE WINDS WILL DEVELOP ON SUNDAY AS WELL...WITH
THE OFFSHORE SURFACE PRESSURE GRADIENTS INCREASING THROUGH TUESDAY.
IN FACT...THE MODELS ARE HINTING AT SOME DECENT UPPER LEVEL SUPPORT
BY TUESDAY...SO WILL NEED TO MONITOR FOR POSSIBLE WIND RELATED
PRODUCTS...AS A MODERATE SANTA ANA MAY DEVELOP.

THIS RIDGE WILL FLATTEN ON WEDNESDAY AND THURSDAY...AS ANOTHER
TROUGH OF LOW PRESSURE MOVES INLAND ALONG THE WEST COAST.  AT THIS
TIME...THE GFS CONTINUES TO BE THE MOST CONSISTENT OF THE
MODELS...KEEPING THIS SYSTEM TO OUR NORTH.  MEANWHILE...THE ECMWF
CONTINUES TO STRUGGLE WITH THE STRENGTH OF THIS TROUGH...FLIP
FLOPPING FROM RUN TO RUN.  THE 12Z ECMWF RUN KEEPS THE IDEA OF RAIN
FOR SOUTHERN CALIFORNIA ON CHRISTMAS...BUT THE SHARP TRAJECTORY OF
THIS SYSTEM MAKES THAT LOOK SOMEWHAT SUSPICIOUS.  THE 12Z GEM LOOKS
EVEN FURTHER OUT TO LUNCH...BRINGING A CUTOFF LOW OVER SOUTHERN
CALIFORNIA ON CHRISTMAS DAY.  THEREFORE...HAVE DISCARDED THE LATTER
TWO MODELS AS LOGICALLY POSSIBILITIES...AND WILL CONTINUE WITH THE
DRIER GFS SOLUTION.  THAT BEING SAID...COOLER CONDITIONS AND ONSHORE
FLOW WILL RETURN FOR WEDNESDAY THROUGH FRIDAY.

&&

.AVIATION...
192100Z...SCT/BKN HIGH CLOUDS THROUGH SAT MORNING. A WEAK
DISTURBANCE MOVING ACROSS THE REGION TONIGHT WILL CREATE THE
POSSIBILITY OF SPRINKLES. HIGH CLOUDS MAY INHIBIT THE DEVELOPMENT OF
BKN/OVC LOW CLOUDS WEST OF THE MOUNTAINS TONIGHT. FORECASTER
CONFIDENCE IN WIDESPREAD LOW CLOUD DEVELOPMENT TONIGHT IS LOW. VIS
OF 3-5 SM BR IS POSSIBLE TONIGHT IN LOW-LYING VALLEY AREAS.

&&

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

&&

.BEACHES...
100 PM...A 6-7 FT/17 SEC PERIOD W SWELL ARRIVING SATURDAY WILL
CREATE ELEVATED SURF ALONG WESTERLY-FACING BEACHES...MAINLY IN
SOUTHERN SAN DIEGO COUNTY AND NORTHERN ORANGE COUNTY. SURF OF 4 TO 7
FEET...WITH ISOLATED SETS TO 8 FEET...IS EXPECTED SATURDAY AFTERNOON
THROUGH SUNDAY...WITH SURF LOWERING THROUGH TUESDAY. MORNING HIGH
TIDES AROUND 7 FEET...COMBINED WITH THE HIGH SURF...MAY CREATE MINOR
COASTAL FLOODING AND TIDAL OVERFLOW. STRONG RIP CURRENTS WILL ALSO
BE POSSIBLE THROUGHOUT THE PERIOD. CONDITIONS WILL BEGIN TO IMPROVE
LATE TUESDAY. A BEACH HAZARD STATEMENT HAS BEEN ISSUED.

&&

.SKYWARN...
SKYWARN ACTIVATION WILL NOT BE NEEDED TODAY.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...BEACH HAZARDS STATEMENT FROM LATE TONIGHT THROUGH TUESDAY
     MORNING FOR THE ORANGE COUNTY COASTAL AREAS...SAN DIEGO
     COUNTY COASTAL AREAS.

PZ...NONE.

&&

$$

PUBLIC...PALMER
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.