Ready for more rain?

FXUS66 KLOX 051918
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1115 AM PST WED DEC 5 2007

.MORNING UPDATE...CONFIDENCE IN RAIN FOR LATE THU/FRI STILL VERY
HIGH, BUT AMOUNTS AND TIMING STILL IN QUESTION. 12Z RUNS ARE
GENERALLY LOWER IN PRECIP TOTALS THAN EARLIER RUNS, PARTICULARLY THE
GFS WHICH HAD BEEN ADVERTISING BETWEEN 1-2 INCHES COASTAL AREAS.
NEWER INFORMATION SEEMS TO LEAN TOWARDS LOWER NUMBERS, BUT STILL A
DECENT RAIN EVENT ACROSS THE AREA. ONSET OF RAIN IS EXPECTED TO BE
SOMETIME THURSDAY NIGHT, PROBABLY EVENING TIME FOR THE CENTRAL COAST
AND LATE EVENING OR EARLY MORNING FRIDAY IN THE LA BASIN. ALTHOUGH
THE RAIN AMOUNTS ARE LOWER THAN EARLIER THAN ANTICIPATED, RAINFALL
INTENSITY WITH THE FRONTAL PASSAGE COULD EASILY EXCEED THE LOW MUD
AND DEBRIS THRESHOLDS FOR THE BURN AREAS. WILL LIKELY ISSUE A WATCH
WITH THE AFTERNOON FORECAST, PROBABLY FOR THURSDAY NIGHT AND FRIDAY.
THE BULK OF THE RAIN EVENT WILL LIKELY BE OVER BY NOON FRIDAY FOR
MOST OF THE AREA. IT LOOKS LIKE A LOT OF THE RESIDUAL SHOWER
ACTIVITY WILL STAY SOUTH AND EAST OF LA COUNTY FRIDAY NIGHT THROUGH
SUNDAY BUT CAN`T RULE OUT A CHANCE OF SHOWERS JUST ABOUT ANYWHERE AS
THE AIRMASS WILL STILL BE MOIST AND SLIGHTLY UNSTABLE.

.SHORT TERM...
WINDS HAVE GREATLY SUBSIDED THIS MORNING AND 06Z MDLS SHOW LITTLE IN
THE WAY OF INCREASE THIS MORNING AND AS A RESULT CANCELLED THE WIND
ADVISORIES.

HGTS FALL THROUGH THE DAY AS FLOW TURNS MORE NWLY. MASSIVE ONSHORE
TRENDS WILL BRING ONSHORE FLOW TO THE AREA BY LATE AFTERNOON AND A
CIRRUS SHIELD WILL MOVE OVERHEAD AS A DISSIPATING COLD (WELL COOL)
FRONT WASHES OUT OVER SLO COUNTY. ALL OF THIS WILL RESULT IN TEMPS 6
TO 10 DEGREES COOLER THAN YDY.

ONSHORE TRENDS AND A SMALL EDDY WILL PROBABLY PRODUCE A WEAK MARINE
LAYER ALONG THE IMMEDIATE COAST TONIGHT...ANNOYINGLY IT COULD
ARRIVE SOME AREAS LATE AFTERNOON.

WHICH LEADS US THE TO STORM...
LATEST MDLS HAVE YET TO CONVERGE ALTHOUGH 06Z NAM DID TREND TO THE
WETTER GFS. EC STILL QUITE DRY AND INSISTS ON A MORE INLAND TRACK TO
THE STORM. PREFER GFS SOLN AS ENSEMBLE SPAGHETTI PLOTS ARE QUITE
SIMILAR AND GFS HAS BEEN FAIRLY CONSISTENT FROM RUN TO RUN. BY 12Z
THU THE UPPER LOW WILL BE JUST OFF THE OREGON COAST WITH THE LEADING
EDGE OF PRECIP NORTH OF THE BAY AREA. BY 00Z THE UPPER LOW IS OVER
EUREKA AND THE RAIN WILL BE FALLING OVER MONTEREY COUNTY AND THERE
IS SLIGHT CHANCE OF RAIN FOR SLO COUNTY. OVERNIGHT THE UPPER LOW
WILL PLUNGE THROUGH THE CENTRAL VALLEY AND DRIVE A RAINBAND FROM SLO
TO L.A. COUNTY. BY FRIDAY AFTERNOON RAIN WILL TURN TO SHOWERS IN THE
UNSTABLE AIR BEHIND THE FRONT JET DYNAMICS ARE ENOUGH FOR A SLIGHT
CHANCE OF THUNDERSTORM. FROM FRIDAY NIGHT TO SATURDAY THE UPPER LOW
WOBBLES AROUND RETROGRADES AND GENERALLY STAYS OVER THE AREA AND
WILL BRING PARTLY OR MOSTLY CLOUDY SKIES AND A SLIGHT CHANCE OR
CHANCE OF SHOWERS TO MOST OF THE AREA ALTHOUGH SLO COUNTY MIGHT BE
SPARED. THIS IS A COLD SYSTEM AND WHILE THE HEAVIEST RAIN BAND WILL
HAVE SNOW LEVELS AROUND 6500 FEET THE SHOWERY PRECIP BEHIND THE
FRONT WILL SNOW DOWN TO 5000 FEET. QPF HAS BEEN VERY HARD TO NAIL
DOWN. ALL RECENT MDLS HAVE NOT FORECAST A GREAT AMOUNT OF SOUTH
WINDS SO DO NOT THINK THERE WILL BE A GREAT AMOUNT OF OROGRAPHIC
INFLUENCE. DAY SHIFTS NUMBERS STILL LOOK LIKE THE BEST JUMPING OFF
POINT WITH 1 TO 3 INCHES AND LOCALLY HIGHER AMOUNTS IN THE MOUNTAINS
AND ANYWHERE A THUNDERSTORM FORMS.

DAY SHIFT HAS ARRANGED A CONFERENCE CALL LATER THIS MORNING TO HASH
OUT EXACT DETAILS ON RAINFALL RATES AND FLASH FLOOD/ DEBRIS FLOW
THREATS. A FLASH FLOOD WATCH WILL LIKELY RESULT FROM THIS MEETING.

WITH ALL THE COLD AIR AND CLOUD COVER TEMPERATURES WILL BE MANY
DEGREES BELOW NORMALS. COASTAL AND VALLEY TEMPS WILL STRUGGLE TO
REACH 65 THURSDAY AND THE WILL BE HARD PRESSED TO EVEN REACH 60 FRI
AND SAT.

.LONG TERM...
UPPER LOW WILL STILL BE AROUND SUNDAY ALTHOUGH IT WILL BE OVER VTA
AND LA COUNTIES. SO SLO AND SBA COUNTIES SHOULD BE OK. WHILE A
CHANCE OR SLIGHT CHANCE OF SHOWERS IS POSSIBLE FOR LA. AND VTA.
TEMPS WILL MODERATE A LITTLE AND COASTAL/VLYS WILL REACH THE MID 60S.

KINDA TROFY THROUGH MID WEEK NEXT WEEK. EVERYTHING LOOKS DRY ATTM
BUT EACH TROF PASSAGE DOES SET UP A LITTLE OFFSHORE EVENT. TEMPS
WILL CLIMB BACK TO NEAR NORMAL.

&&

.AVIATION...05/1915Z
EXPECT VFR CONDITIONS WILL PREVAIL TODAY...WITH SOME SCT015 DECKS
POSSIBLE NEAR KLAX. LLWS WILL BE OF CONCERN TODAY AT KSBA KBUR AND
KVNY THROUGH 20Z...WITH ANOTHER SHOT TONIGHT. LOW CLOUDS AND FOG
WILL RETURN TO MANY LOCATIONS TONIGHT DUE TO INCREASING ONSHORE FLOW
AND A DEVELOPING CATALINA EDDY.

KLAX...A LOW CONFIDENCE FORECAST IN TERMS OF THE TIMING OF THE
RETURN OF LOW CLOUDS AND FOG. A BANK OF LOW CLOUDS IS LURKING OFF
THE COAST OF KLAX AND INCREASING ONSHORE FLOW MAY BE STRONG ENOUGH
TO BRING THE LOW CLOUDS AND FOG INTO THE AIRFIELD BY LATE AFTERNOON.
LOW CLOUDS AND FOG ARE LIKELY TONIGHT WITH A CEILING ABOVE 1000 FEET.

KBUR...GOOD CONFIDENCE THAT CLEAR SKIES AND GOOD VISIBILITIES WILL
CONTINUE THROUGH THIS EVENING BEFORE LOW CLOUDS AND FOG RETURN TO
THE AIRFIELD AFTER MIDNIGHT. THE CEILING WILL MOVE IN AT AROUND 1000
FEET.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
GALE WARNING (SEE LAXCWFLOX).
SMALL CRAFT ADVISORY (SEE LAXCWFLOX).
HIGH SURF ADVISORY (SEE LAXCFWLOX).
HIGH RIP CURRENT RISK (SEE LAXSRFLOX).

&&




PUBLIC...WOFFORD/RORKE
AVIATION...SWEET

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