Strong Storm Coming

AREA FORECAST DISCUSSION

FXUS66 KLOX 251801
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1001 AM PST SAT FEB 25 2006

.SHORT TERM...(TODAY THROUGH MONDAY NIGHT) LOW CLOUDS WERE FAIRLY
WDSPRD ACRS THE CSTL PLAIN THIS MORNING. INVERSION HAS RISEN A
BIT...ALLOWING SOME CLOUDS TO SNEAK INTO A FEW VLY ZONES...BUT ONLY
PATCHY COVERAGE THERE. STILL SHALLOW ENOUGH FOR SOME LOCALLY DENSE
FOG. LOW CLOUDS SHOULD BURN OFF THIS MORNING...BUT A SWATH OF MID
AND HIGH CLOUDS SHOULD MOVE INTO THE AREA FROM THE SW TODAY...SO
PARTLY CLOUDY WORDING LOOKS GOOD. XPCT MAX TEMPS IN MOST AREAS TO BE
FAIRLY SIMILAR TO THOSE REACHED FRI.

THE POWERFUL TROUGH TAKING SHAPE IN THE PAC WILL SLOWLY APCH THE W
CST SUNDAY THRU MONDAY. SHOULD STILL BE SOME MARINE LAYER CLOUDINESS
TONIGHT...ALTHOUGH THE INCREASE IN MID AND UPPER LVL MSTR COULD
CAUSE A DISRUPTION OF THE INVERSION. XPCT A GOOD DEAL OF MID AND
HIGH LVL CLDS TO SPREAD INTO AT LEAST AREAS N OF PT CONCEPTION
OVERNIGHT...AND BLV SUNDAY WILL JUST BE MOSTLY CLDY ACRS THE AREA.
MODELS CONT TO SHOW QUITE AN INCREASE IN LOW LVL MSTR AND SLY FLOW
ON SUNDAY...ESPECIALLY ACRS SLO AND SBA COUNTIES. HAVE BUMPED UP
POPS A BIT...BUT LATER SHIFTS MAY NEED TO BUMP THEM INTO THE LIKELY
CATEGORY FOR SLO AND SBA COUNTIES FOR SUNDAY...AT LEAST IN THE
AFTERNOON...AS CROSS SECTIONS GET INCREASINGLY MOIST.

MSTR CONTS TO DEEPEN ACRS THE AREA SUNDAY NIGHT AS DEEP SLY FLOW
CONTS TO INCREASE IN STRENGTH. THIS IS ESPCIALLY TRUE ACRS SLO
AND SBA COUNTIES...WHERE RAIN IS AT LEAST LIKELY IF NOT A SURE
BET SUN NIGHT. XPCT QUITE A BIT OF OROGRAPHIC ENHANCEMENT...SO THERE
COULD BE SOME LOCALLY HEAVY RAIN ACRS SLO AND SBA COUNTIES AS EARLY
AS SUNDAY NIGHT. ALSO...HAVE BUMPED POPS INTO THE LIKELY CATEGORY
ACRS THE MTNS OF VTU AND L.A. COUNTIES...ESPECIALLY CSTL SLOPES WITH
THE INCREASINLGY STRONG AND MOIST UPSLOPE FLOW. SOUTHERLY WINDS WILL
LIKELY REACH AT LEAST WIND ADVISORY LEVELS SUNDAY NIGHT IN THE
MTNS...AND POSSIBLY ACRS MUCH OF SLO AND SBA COUNTIES.

THE REAL "FUN" BEGINS ON MONDAY AS THE VERY STRONG FULL-LATITUDE
TROUGH SWINGS EWD TOWARD THE FCST AREA...AND BEGINS TO TAKE ON A
NEGATIVE TILT. AS HGTS FALL...AND AN INCREASINGLY DIFFLUENT
UPPER HGT PATTERN REACHES THE CST...MID LVL DYNAMICS WILL INCREASE
DRAMATICALLY. NOT ONLY WILL THE SYSTEM BE A DYNAMIC ONE...IT WILL BE
ONE WITH A SOLID SUBTROPICAL CONNECTION...TAPPING INTO A RICH MSTR
FIELD IN THE ERN PAC...AND PRECIPITABLE WATER VALUES ARE FCST TO
RISE TO OVER 1.5 INCHES JUST OFF THE CST OF SRN CA BY MON.

STRONG SLY FLOW NEAR THE SFC...WITH 55 TO 65 MPH SLY WINDS AT 850 MB
WILL PROVIDE VERY GOOD OROGRAPHIC ENHANCEMENT OF THE RAIN ON S AND
SW FACING SLOPES. A POTENT SFC FRONT WILL ALSO SWEEP THRU THE AREA
AS THE TROUGH AXIS PUSHES INTO THE W CST. THE 06Z RUNS HAVE SLOWED
THINGS DOWN A BIT...ESPECIALLY ACRS L.A. COUNTY...AS A STRONG SFC
WAVE DEVELOPS TO THE W OF PT CONCEPTION. IT LOOKS LIKE THE MOST
INTENSE RAIN WILL AFFECT SAN LUIS OBISPO AND SANTA BARBARA COUNTIES
MON INTO MON NIGHT...AND VTU AND L.A. COUNTIES MONDAY AFTERNOON OR
EVENING INTO TUE MORNING. [b[RAINFALL RATES COULD REACH ONE INCH PER
HOUR[/b] IN OROGRAPHICALLY FAVORED LOCATIONS...MAINLY ON AND BELOW S AND
SW FACING SLOPES DURING THE HEIGHT OF THE STORM. EVEN THOUGH UPPER
LVLS OF THE ATMOSPHERE WILL NOT BE PARTICULARLY COLD...THIS SYSTEM
WILL BE SO DYNAMIC...THAT A THUNDERSTORM OR TWO CAN NOT BE RULED
OUT. WILL LET LATER SHIFTS ASSESS THAT FURTHER.

FLASH FLOOD WATCHES WILL ALMOST CERTAINLY HAVE TO BE ISSUED FOR THE
BURN AREAS...AND POSSIBLY IN OTHER LOCATIONS AS WELL. RESIDENTS OF
SRN CA...ESPECIALLY THOSE IN AND NEAR RECENTLY BURNED AREA SHOULD
USE THIS WEEKEND TO TAKE STEPS TO PROTECT THEIR PROPERTY IN CASE THE
SYSTEM IS AS STRONG AND WET AS THE LATEST COMPUTER MODELS INDICATE.

VERY STRONG SE TO SLY WINDS WILL LIKELY REQUIRE ADVISORIES ACRS MUCH
OF THE AREA...AND WINDS COULD APCH OR EXCEED HIGH WIND WARNING LEVELS
IN THE MTNS...ACROSS MUCH OF SLO AND SBA COUNTIES...AND EVEN IN
THE HIGHER TERRAIN OF THE VLYS. THIS STORM WILL PRODUCE GALE FORCE
WINDS ACRS THE ENTIRE COASTAL WATERS...WITH STORM FORCE WINDS A
POSSIBILITY ACRS THE NORTHERN AND OUTER WATER

RAINFALL TOTALS WILL BE VERY IMPRESSIVE WITH THIS SYSTEM...ON THE
ORDER OF 2 TO 4 INCHES IN COASTAL AND VALLEY AREAS...WITH 5 TO 10
INCHES IN THE FOOTHILLS AND MOUNTAINS. SNOW LEVELS WILL BE VERY
HIGH FOR THE BULK OF THIS STORM...PROBABLY ABOVE RESORT LEVELS
THROUGH AT LEAST LATE MONDAY NIGHT.

.LONG TERM...RAIN WILL DECREASE ACRS SLO AND SBA COUNTIES
LATE MONDAY NIGHT...BUT IS STILL LIKELY ACRS L.A. COUNTY TUESDAY
MORNING. OTHERWISE...JUST A CHANCE OF RAIN OR SHOWERS ACRS THE
AREA TUESDAY AFTERNOON. CYCLONIC FLOW WILL CONT ACRS THE AREA FOR
MUCH OF THE WEEK. ADDITIONAL VORTS MOVING INTO THE WEST COAST MAY BE
ENOUGH TO BRING A SLIGHT CHANCE OF SHOWERS TO NRN SXNS OF THE FCST
AREA WED NIGHT THRU FRI...WITH A SLIGHT CHANCE OF RAIN SPREADING
INTO SRN SNXS THU NIGHT AND FRO MORNING. IT WILL BE COOLER WITH
LOWER SNOW LEVELS...BUT PRECIP AMOUNTS WED THRU FRI LOOK TO BE QUITE
LIGHT.

&&

.AVIATION...TROUGH UPSTREAM WILL PERSIST AND APPROACH THE AREA.
MODERATE UPPER LEVEL WEST FLOW WILL BECOME MODERATE SOUTHWEST WITH
INCREASING MID AND UPPER LEVEL MOISTURE. LOW LEVEL STRATUS FIELD
EXTENDING WEST OVER THE OFFSHORE WATERS WILL RETURN TO THE THE
COASTAL SITES THIS EVENING WITH AN EARLIER RETURN TO SB AND SLO
COUNTY SITES WITH VIS AND CIGS SIMILAR OR LESS RESTRICTIONS AS THE
TROUGH UPSTREAM APPROACHES. FREEZING LEVEL WAS AROUND 11KFT THIS
MORNING AND WILL ASCEND SEVERAL HUNDRED FEET OVERNIGHT.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
SPECIAL WEATHER STATEMENT (SEE LAXSPSLOX).
HYDROLOGIC STATEMENT (SEE LAXESFLOX).

&&





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