393  
FXUS66 KLOX 221100  
AFDLOX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA  
300 AM PST MON JAN 22 2018  
   
SYNOPSIS
 
 
CONDITIONS WILL BE PRIMARILY WARM AND DRY THROUGH EARLY NEXT  
WEEK, THOUGH THERE IS A SLIGHT CHANCE OF LIGHT SHOWERS ALONG THE  
CENTRAL COAST TODAY. A WEAK COLD FRONT WILL PUSH THROUGH THE  
REGION LATER IN THE WEEK, BRINGING COOLER TEMPERATURES, GUSTY  
WINDS, AND POSSIBLE RAIN AND MOUNTAIN SNOW SHOWERS.  
 

 
   
SHORT TERM
 
(TDY-WED)  
 
THE LATEST SATELLITE IMAGERY SHOWED A COLD FRONT SAGGING SOUTH  
THROUGH CENTRAL CALIFORNIA WITH ASSOCIATED MID AND HIGH LEVEL  
CLOUDS DISSIPATING. THIS IS A SIGN THAT THE FRONT IS WEAKENING.  
SCATTERED SHOWERS ALONG AND JUST AHEAD OF THE FRONT WERE PUSHING  
THROUGH THE BAY AREA WITH MEASURABLE RAIN NEARING MONTEREY. THIS  
FRONT WILL CONTINUE TO WEAKEN AS IT TRIES TO PUSH THROUGH SAN  
LOUIS OBISPO COUNTY LATE THIS MORNING INTO EARLY IN THE AFTERNOON.  
THERE IS A CHANCE OF VERY LIGHT SHOWERS DURING THIS TIME FOCUSED  
ACROSS FAR NORTHWEST SLO COUNTY AND ADJACENT WATERS. OTHERWISE  
MOSTLY CLOUDY SKIES WILL PREVAIL NORTH OF POINT CONCEPTION TODAY  
WITH PARTY CLOUDY TO SUNNY SKIES TO THE SOUTH. MODERATE OFFSHORE  
FLOW FOCUSED TO THE SOUTH OF POINT CONCEPTION WILL BRING BREEZY  
WINDS TO AREAS PRONE TO NORTH WINDS. A FEW DEGREES OF WARMING IS  
EXPECTED TODAY WITH HIGHS FOR MOST COASTAL AREAS IN THE 60S TO  
LOW 70S.  
 
A MODEST 1037 MB SURFACE HIGH PRESSURE SYSTEM IS EXPECTED TO BUILD  
IN BEHIND THE DEPARTING COLD FRONT TUESDAY INTO WEDNESDAY. THIS  
WILL BRING AN UPTICK IN OFFSHORE FLOW BY TUESDAY LATE MORNING  
CONTINUING INTO WEDNESDAY MORNING, SUPPORTING BREEZY OFFSHORE  
WINDS. THE INCREASE IN OFFSHORE WINDS AND A RIDGE OF HIGH PRESSURE  
BUILDING IN ALOFT WILL SUPPORT 5 TO 10 DEGREES OF WARMING FOR  
MANY AREAS, GREATEST FOR COASTAL AREAS SOUTH OF POINT CONCEPTION  
TUESDAY WITH CONTINUED WARM CONDITIONS FOR MOST AREAS WEDNESDAY.  
ALTHOUGH A SWITCH TO ONSHORE FLOW FOR THE CENTRAL COAST MAY  
SUPPORT SOME COOLING THERE WEDNESDAY WITH PATCHY LOW CLOUDS AND  
FOG POSSIBLY RETURNING DURING THE LATE AFTERNOON OR EVENING  
HOURS. MID AND HIGH LEVEL CLOUDS WILL LIKELY BE ON THE INCREASE  
FROM NORTH TO SOUTH LATE WEDNESDAY. THERE IS THE SLIGHT CHANCE OF  
LIGHT SHOWERS FOR THE SLO PORTION OF THE CENTRAL COAST LATE  
WEDNESDAY AHEAD OF A COLD FRONT APPROACHING FROM THE NORTHWEST.  
   
LONG TERM
 
(THU-SUN)  
 
ABOVE AVERAGE MODEL AGREEMENT CONTINUES INTO THE LONG TERM  
PROVIDING ABOVE AVERAGE CONFIDENCE IN THE FORECAST DETAILS.  
HOWEVER, MODEL TRENDS HAVE BACKED OFF ON THE STRENGTH OF A COLD  
FRONT AND ASSOCIATED PRECIPITATION FOR THURSDAY INTO FRIDAY. THE  
COLD FRONT IS CURRENTLY EXPECTED TO PUSH THROUGH THE REGION FROM  
WEST TO EAST THURSDAY WITH MAINLY LIGHT SHOWERS FOCUSED NORTH OF  
POINT CONCEPTION. THOUGH THERE IS A SLIGHT CHANCE OF LIGHT SHOWERS  
WORKING THERE WAY DOWN TO VENTURA COUNTY AND THE MOUNTAINS OF LOS  
ANGELES COUNTY. HAVE CUT RAINFALL AMOUNTS IN HALF WITH THIS  
FORECAST PACKAGE. MOST AREAS WILL LIKELY SEE ONE TENTH OF AN INCH  
OR LESS (AGAIN FOCUSED TO THE NORTH OF POINT CONCEPTION), EXCEPT  
THE COASTAL RANGE OF SLO COUNTY WHERE UP TO AROUND ONE QUARTER OF  
AN INCH IS POSSIBLE. SNOW LEVELS, INITIALLY HIGH (ABOVE 7000  
FEET) COULD DROP TO AS LOW AS AROUND 4000 FEET BEHIND THE FRONT.  
HOWEVER, WITH THE LIGHTER PRECIPITATION AMOUNTS CURRENTLY  
EXPECTED, LIGHT SNOW ACCUMULATIONS WOULD LIKELY BE RESERVED TO  
THE HIGHEST ELEVATIONS. LOWER HEIGHTS/THICKNESSES AND CLOUD COVER  
WILL BRING NEAR TO BELOW NORMAL TEMPERATURES (60S FOR COASTAL  
AREAS AND 50S FOR INTERIOR) TO THE REGION THURSDAY WITH LIMITED  
WARMING FRIDAY.  
 
SURFACE HIGH PRESSURE BUILDING INTO THE GREAT BASIN BY FRIDAY,  
THEN SHIFTING EAST TO THE CENTRAL ROCKIES OVER THE WEEKEND. THIS  
MAY SUPPORT ADVISORY LEVEL NORTH WINDS LATE THURSDAY INTO FRIDAY  
FOCUSED ACROSS THE MOUNTAINS AND SOUTHERN SANTA BARBARA COUNTY  
WITH A WEAK TO MODERATE SANTA ANA POSSIBLE FOR THIS UPCOMING  
WEEKEND. A MODERATE RIDGE OF HIGH PRESSURE ALOFT (H5 AROUND 580  
DM) WILL LIKELY BUILD INTO THE REGION BY NEXT WEEKEND. THIS  
COMBINED WITH THE OFFSHORE FLOW WILL BRING CONSIDERABLE WARMING  
AND DRYING FOR THIS WEEKEND WITH HIGH TEMPERATURES POSSIBLY  
BREAKING 80 ACROSS WARMER VALLEYS AND INTERIOR COASTAL AREAS.  
 

 
   
AVIATION
 
22/1100Z  
 
AT 0927Z AT KLAX, THERE WAS NO MARINE LAYER, THERE WAS A SFC BASED  
INVERSION WITH A TOP OF 400 FEET AND A TEMPERATURE OF 14 DEGREES  
C.  
 
HIGH CONFIDENCE IN CAVU TAFS. THERE IS A 20 PERCENT CHC OF SOME  
SPRINKLES OVER SLO COUNTY THIS MORNING.  
 
KLAX AND KBUR...HIGH CONFIDENCE IN CAVU TAF.  
 

 
   
MARINE
 
22/300 AM  
 
ACROSS THE SOUTHERN OUTER WATERS ZONES (PZZ673, PZZ676) SCA CONDS  
FOR SEAS ARE LIKELY MUCH OF THE TIME THROUGH TUE NIGHT DUE TO A  
COMBINATION OF WINDS AND SEAS.  
 
ACROSS THE NORTHERN OUTER WATERS ZONE (PZZ670) SCA CONDS ARE  
LIKELY AGAIN THRU TONIGHT DUE TO SEAS. SCA SEAS ARE EXPECTED TO  
MOVE INTO THE NEARSHORE WATERS NORTH OF POINT SAL (PZZ645) DURING  
THIS TIME AS WELL.  
 
ACROSS THE SBA CHANNEL AND THE SOUTHERN INNER WATERS, SCA CONDS  
ARE NOT EXPECTED UNTIL THU.  
 
ANOTHER LONG PERIOD SWELL IS EXPECTED THU INTO FRI.  
 

 
   
LOX WATCHES/WARNINGS/ADVISORIES
 
 
CA...HIGH SURF ADVISORY IN EFFECT UNTIL 4 AM PST TUESDAY FOR ZONES  
34-35. (SEE LAXCFWLOX).  
PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS IN EFFECT UNTIL 4 AM  
PST TUESDAY FOR ZONES 645-670. (SEE LAXMWWLOX).  
SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 AM PST WEDNESDAY FOR  
ZONES 673-676. (SEE LAXMWWLOX).  
 

 
   
HAZARD POTENTIAL OUTLOOK
 
(WED-SUN)  
GUSTY WINDS ARE POSSIBLE THURSDAY AND FRIDAY OVER THE MOUNTAINS  
AND SOUTHERN SANTA BARBARA COUNTY. GUSTY SANTA ANA WINDS COULD  
DEVELOP OVER NEXT WEEKEND.  
 

 
 

 
 
PUBLIC...MUNROE  
AVIATION...RORKE  
MARINE...RORKE  
SYNOPSIS...KJ  
 
WEATHER.GOV/LOSANGELES  
 
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