SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
AFDLOX 300 AM PST SAT FEB 10 2001
WATER VAPOR IMAGER SHOWED FAIRLY STG AND COLD UPPER LOW CENTERED ACRS
NRN CA. FRONTAL BAND WAS CURRENTLY LOCATED ACROSS ERN VTU COUNTY AND
WRN L.A. COUNTY. THE BACK EDGE OF THE STEADY RAINFALL SHOULD MOVE
ACROSS MOST OF L.A. COUNTY BY MID MORNING...ALTHOUGH AS IS TYPICAL...
IT WILL TEND TO GET HUNG UP ACRS ERN SXNS BY THE MTNS. RAINFALL TOTALS
FROM THIS BAND HAVE GENERALLY BEEN BETWEEN ONE HALF INCH AND THREE
QUARTERS OF AN INCH ACRS SLO AND SBA COUNTIES...WITH LCLLY HIGHER
TOTALS IN OROGRAPHICALLY FAVORED LOCATIONS. HOWEVER...THE BAND HAS
WKND A BIT...PRODUCING BETWEEN A QUARTER OF AN INCH AND ONE HALF
INCH ACRS CSTL VTU COUNTY...WITH AMTS APCHG ONE INCH IN THE FOOTHILLS
AND MTNS. BLV SIMILAR AMOUNTS WILL OCCUR IN L.A. COUNTY EARLY THIS
MORNING. ACARS SOUNDING SHOWED SNOW LEVELS WERE LIKELY RUNNING AROUND
3500 FEET...AND MAY DROP A BIT MORE EARLY THIS MORNING...DOWN TO
ABOUT 3000 FEET IN MOST AREAS.
BEHIND THE BAND OF STEADY RAIN...SCATTERED SHOWERS WERE OCCURRING
IN THE MOIST CYCLONIC WLY FLOW AROUND THE SRN SIDE OF THE UPR LOW.
STG VORT CENTER NEAR 35N/126 W WAS BEGINNING TO CAUSE A SIGNIFICANT
INCREASE IN SHWR ACTIVITY AND INTENSITY OFSHR...WITH OCNL LIGHTNING
STRIKES DETECTED. MODELS BRING THIS VORT RIGHT ACRS THE FCST AREA
LATER THIS MORNING AND EARLY THIS AFTERNOON. THEREFORE...XPCT PLENTY
OF SHOWERS ACRS THE FCST AREAS TODAY...SOME LCLLY HEAVY. ALSO BLV
THERE WILL BE SCT THUNDERSTORMS...AND GIVEN THE TEMP PROFILE THRU
THE ATMOSPHERE...SOME OF THEM MAY PRODUCE SMALL HAIL. COULD BE
QUITE AN ACTIVE DAY ACRS THE FCST AREA. BLV MANY AREAS COULD RECEIVE
AN ADDITIONAL QUARTER TO HALF INCH OF RAIN TODAY WITH LCLLY HEAVIER
TOTALS QUITE POSSIBLE.
SHOWER ACTIVITY WL DECREASE ACROSS THE AREA THIS EVENING AND
EARLY TONIGHT...ALTHOUGH WITH MOIST WLY FLOW...XPCT SCT SHWRS
TO CONT THRU THE NIGHT. NEXT UPSTREAM UPR LVL SYSTEM WILL BE RIGHT
ON THE HEELS OF THIS CURRENT ONE...WILL SPREAD STEADY RAIN INTO
THE CENTRAL CST SUNDAY MORNING. THIS NEXT SYSTEM LOOKS TO BE
STRONGER AND WETTER THAN THE ONE CURRENTLY MOVG ACRS THE FCST
AREA. THE UPR SYSTEM IS PROGGED TO DROP NEARLY DUE SWD THROUGH
SUNDAY...TRACKING FROM A POSN OFF THE WASHINGTON COAST THIS
AFTERNOON...TO OFF THE NRN CA CST BY SUNDAY AFTERNOON. INCRGLY
STG AND MOIST MID LVL SWLY FLOW AND STG MID LVL DYNAMICS/UPWARD
MOTION WILL WORK SWD INTO THE FCST AREA SUNDAY...AS A SOLID
FRONTAL BAND ASSOCD WITH THE BAROCLINIC ZONE S OF THE UPR SYSTEM
PUSHES INTO THE REGION. LOW LVL FLOW WILL BECOME SLY...WHICH WILL
INCRS LOW LVL CONVERGENCE/LIFT AND ALLOW FOR OROGRAPCHIC ENHANCEMENT
OF THE RAINFALL. SLY WINDS COULD APCH ADVISORY LVLS ON THE CENTRAL
CST LATE SUNDAY OR SUNDAY NIGHT. LOOKS LIKE STEADY RAIN WILL PUSH
INTO SLO/SBA COUNTIES SUNDAY MORNING WITH RAIN BECOMING HVY AT
TIMES...WITH RAIN MOVING INTO L.A. COUNTY BY LATE AFTERNOON OR
EVENING. RAIN SHOULD CONT SUNDAY NIGHT...POSSIBLY HVY AT TIMES.
THE UPR LOW WILL CONT TO DROP SLOWLY SOUTH JUST OFF THE CA CST
THRU MON. THE AVN KEEPS THE CENTER OF THE UPR LOW OFF THE CST
THRU MONDAY NIGHT...EVENING AT WHICH POINT IT WILL BE JUST SW
OF PT CONCEPTION. THIS WILL KEEP THE FCST AREA IN STG MOIST
SWLY FLOW...WITH SEVERAL VORTS HELPING TO CAUSE PERIODS OF
RAIN THRU AT LEAST EARLY TUE. COULD BE SOME DECENT RAINFALL TOTALS
FROM SUNDAY THROUGH TUE. OF COURSE...THE KEY TO THIS WILL BE
THE TRACK OF THE UPR LOW. SIGNIFICANLY LESS RAINFALL CAN BE
XPCTD IF THE UPR SYSTEM DOES NOT REMAIN OFF THE CST AS IT DROPS
SWD LATE SUNDAY THROUGH TUE.
SNOW LVLS WILL LIKELY RISE SOMEWHAT ON SUNDAY AS H85 TEMPS INCREASE
IN SWLY FLOW ALF. INDICATED SNOW LVLS RISING TO 4000 FEET. IT
MAY ACTUALLY RISE MORE THAN THAT FOR A WHILE LATE SUNDAY...BUT
SHOULD BEGIN TO LOWER AGAIN SUNDAY NIGHT. NEEDLESS TO SAY...
SKI RESORTS MAY BE MEASURING SNOWFALL IN FEET RATHER THAN INCHES
BETWEEN TODAY AND TUE.
UPR SYSTEM STILL HANGS AROUND FOR A CHANCE OF SHOWERS ACRS THE
FCST AREA WED. MRF/AVN SHOW A DECRG THREAT OF SHWRS BU THU
AS UPR LOW BEGINS TO MOV AWAY FROM THE FCST AREA. HOWEVER...
ECMWF SHOWS A DIFFERENT STORY...KEEPING IT AROUND...SO CONFIDENCE
IN THE FCST FOR THU AND FRI IS FAIRLY LOW.
LAX 937. BRUNO.
.LAX...WINTER STORM WARNING/WINTER WEATHER ADVISORY (SEE LAXWSWLAX).
HEAVY SURF ADVISORY (SEE LAXMWSLAX).
SMALL CRAFT ADVISORY (SEE LAXCWFLAX).