SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
205 AM PST SAT FEB 1 2014

SYNOPSIS...

PARTLY CLOUDY AND BREEZY CONDITIONS AND SEASONABLY COOL WEATHER WILL CONTINUE TODAY.  A LOW PRESSURE SYSTEM APPROACHING FROM THE NORTHWEST WILL BRING A CHANCE OF SHOWERS TO THE REGION SUNDAY AFTERNOON THROUGH EARLY MONDAY MORNING. COOL WEATHER WILL LIKELY CONTINUE THROUGH NEXT WEEK DUE TO A BROAD UPPER TROUGH OVER THE WESTERN HALF OF THE COUNTRY.

SHORT TERM (TODAY-MON)...LATEST SATELLITE IMAGERY INDICATED MOSTLY CLEAR SKIES ACROSS THE FORECAST AREA. THERE WERE A FEW CLOUDS BANKED UP AGAINST THE NRN SLOPES OF THE VENTURA AND WESTERN LA COUNTY MOUNTAINS.  THE WATER VAPOR IMAGERY SHOWED AN AREA OF SUBSIDENCE THAT MOVED OVER THE AREA OVERNIGHT. THIS DOWNWARD MOTION WAS LIKELY THE REASON THERE WAS A SURGE OF NORTHERLY WINDS THAT AFFECTED MANY PARTS OF LA COUNTY OVERNIGHT.  WINDS SHOULD SETTLE DOWN ACROSS THE LA BASIN EARLY THIS MORNING...BUT EXPECT WINDY CONDITIONS TO CONTINUE ACROSS THE LA/VTU COUNTY MOUNTAINS INCLUDING THE SANTA MONICA MOUNTAINS THROUGH THIS AFTERNOON.  A WIND ADVISORY IS IN EFFECT FOR THE MOUNTAINS AND ADDED THE SANTA MONICA RANGE THROUGH 3 PM THIS AFTERNOON.  IT WILL REMAIN BREEZY ACROSS THE LA/VTU COUNTY VALLEYS AS WELL BUT WINDS SHOULD REMAIN BELOW WIND ADVISORY THRESHOLDS.

A SHORTWAVE MOVING SOUTH ACROSS THE EASTERN PORTION OF CALIFORNIA LATER TODAY WILL QUICKLY MOVE THROUGH THE STATE BRINGING SOME ADDED COOLING TO THE INTERIOR SECTIONS TODAY.  WITH WEAK LOW LEVEL OFFSHORE EXPECTED TODAY...TEMPS SHOULD BE A TAD WARMER TODAY FOR THE COAST AND COASTAL VALLEYS...WITH THE INTERIOR REGION REMAINING QUITE COOL...INCLUDING THE ANTELOPE VALLEY WHERE HIGH TEMPS ARE EXPECTED TO REMAIN IN THE LOWER 50S. OVERALL HIGH TEMPS WILL REMAIN A FEW DEGREES BELOW NORMAL ACROSS MOST OF THE FORECAST AREA WITH HIGHS IN THE LOWER TO MID 60S...EXCEPT THE LA COAST WHERE HIGHS SHOULD REACH AROUND 68 TODAY.

FOR TONIGHT...SKIES SHOULD REMAIN CLEAR EARLY...THEN BECOME PARTLY CLOUDY AS HIGH CLOUDS PUSH AHEAD OF ANOTHER CUTOFF UPPER LOW UPSTREAM JUST OFF THE COAST OF NORTHERN CAL.  TEMPS WILL DIP QUITE A BIT ACROSS THE INTERIOR AREAS OVERNIGHT WITH LOW TEMPS IN THE LOWER TO MID 20S FOR THE ANTELOPE VALLEY AND MID 20S LIKELY FOR THE SLO INTERIOR VALLEYS.  THESE AREAS HAVE ALREADY BEEN AFFECTED WITH SEVERAL HARD FREEZES ALREADY THIS WINTER SO NO HARD FREEZE WARNINGS WILL BE ISSUED. HOWEVER...THE CENTRAL COAST...SANTA YNEZ VALLEY AND PORTIONS OF THE SANTA BARBARA SOUTH COAST WILL BE JUST AROUND THE FREEZING LEVEL. WILL LET THE DAY SHIFT TAKE A CLOSER LOOK FOR POSSIBLE ISSUANCE OF FROST ADVISORIES FOR THESE AREAS. NEVERTHELESS LESS...THERE WILL BE PATCHY FROST ACROSS THESE AREAS AND THE OJAI VALLEY.

BY SUNDAY...MOST MODELS HAVE THE UPPER LOW APPROACHING SAN FRANCISCO WITH A COLD FRONT EXTENDED TO THE SW.  MODELS HAVE INDICATED A SLOWING OF THE PROGRESSION OF THE UPPER LOW AND HAVE ADJUSTED THE TIMING OF THE POPS ACCORDINGLY.  FOR THE MOST PART...SKIES WILL BECOME MOSTLY CLOUDY WITH INCREASING CHANCES OF LIGHT RAIN MAINLY ACROSS THE CENTRAL COAST AFTER NOON...THEN SPREAD SOUTH INTO SANTA BARBARA COUNTY.  BEST CHANCE OF PRECIP WILL OCCUR CLOSEST TO THE COAST.  EXPECT ANOTHER CHILLY DAY WITH HIGH TEMPS IN THE UPPER 50S TO LOWER 60S FOR MOST COAST AND VALLEYS. BY SUNDAY EVENING...THE UPPER LOW WILL BE OVER THE ADJACENT COASTAL WATERS OFF SANTA BARBARA/VENTURA/LA COUNTIES.  THE BEST JET DYNAMICS SEEM TO STAY TO THE NORTH AND SOUTH OF OUR FORECAST AREA AS THE UPPER LOW DIVES SOUTH. HOWEVER...500 MB TEMPS WITH THE UPPER LOW ARE EXPECTED TO BE AROUND -28 DEGREES C. AND ALTHOUGH THE TIMING IS OUT OF SYNC WITH THE BEST HEATING OF THE DAY TO HELP DESTABILIZE THE ATMOSPHERE...THERE WILL BE ENOUGH INSTABILITY TO ADD A SLIGHT CHANCE OF THUNDERSTORMS TO THE ADJACENT COASTAL WATERS AS THE LOW MOVES DOWN THE COAST.

FINAL RAINFALL TOTALS SHOULD REMAIN BELOW A QUARTER OF AN INCH...WITH HIGHEST TOTALS AROUND THE SANTA BARBARA CENTRAL COAST AND SANTA YNEZ MTN RANGE.  AS FAR AS SNOW...WITH SNOW LEVELS EXPECTED TO BE BETWEEN 4000 AND 4500 FT BY SUNDAY EVENING...LOCALLY DOWN TO 3500 FT...THERE COULD BE SOME TRAVEL ISSUES ACROSS THE I-5 CORRIDOR SUNDAY EVENING INTO EARLY MONDAY MORNING DUE TO ICY ROAD CONDITIONS. BASED ON LIGHT PRECIP TOTALS...NOT EXPECTING MORE THAN A FEW INCHES OF SNOW ABOVE 5000 FT.

BY MONDAY MORNING...MOST OF THE PRECIPITATION WILL HAVE PASSED TO THE SOUTH AND EAST...WITH ONLY LA COUNTY EXPECTED TO SEE SOME LINGERING MORNING SHOWERS. HAVE ADDED A SLIGHT CHANCE OF TSTMS TO THE LA COUNTY COAST AND VALLEYS AS WELL FOR MONDAY MORNING. OTHERWISE...SKIES SHOULD CLEAR OUT FROM THE NORTH WITH PARTLY CLOUDY SKIES LIKELY FOR AREAS SOUTH OF SANTA BARBARA...AND MOSTLY CLOUDY SKIES AROUND THE MOUNTAINS. TEMPS WILL CONTINUE TO BE QUITE COOL WITH VERY LITTLE CHANGE FROM SUNDAY`S HIGH. IN THE WAKE OF THE UPPER LOW PUSHING INTO NRN BAJA....NORTHWEST WINDS WILL DEVELOP LIKELY AFFECTING THE SANTA BARBARA COUNTY MOUNTAINS AND ADJACENT SOUTH COAST WHERE A WIND ADVISORY WILL LIKELY BE NEEDED. ALSO...BREEZY CONDITIONS FOR THE THE I-5 CORRIDOR AND ANTELOPE VALLEY ARE LIKELY.