SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
AFDLOX 300 AM PST FRI FEB 15 2002
LOW CLDS WERE WDSPRD ACRS CSTL SXNS OF THE FCST AREA N OF PT CONCEPTION
EARLY THIS A.M.. BAND OF HIGH CLOUDS CONTD TO STREAM ACRS SRN SXNS OF
THE FCST AREA...BUT SO FAR JUST PATCHY STRATUS WAS BEING REPORTED IN
CSTL SXNS S OF PT CONCEPTION ALONG WITH QUITE A BIT OF FOG. STRATUS
FIELD ACRS THE CSTL WATERS WAS BEGINNING TO SURGE TOWARD THE CST...AND
XPCT AN INCRS IN LOW CLDS IN CSTL ZONES S OF PT CONCEPTION BY SUNRISE.
ACARS DATA SHOWED MARINE INVERSION ARD 2000 FT EARLY THIS A.M....SO
SOME STRATUS COULD PUSH INTO THE VLYS AS WELL...BUT WITH ONSHR GRADS
STILL FAIRLY WEAK...THIS IS BY NO MEANS A CERTAINTY. UPR LOW OFF THE
CST OF CNTRL CA WAS BEGINNING TO LIFT ENEWD THIS A.M.. AS IT APCHS THE
NRN CA CST TODAY...INCRG DIFLUENCE ALF ACRS THE FCST AREA WL LIKELY
ENHANCE SOME OF THIS MID AND HIGH CLOUDINESS TODAY...SO IT WL PROBABLY
END UP AVERAGING PARTLY TO MOSTLY CLDY ACRS THE FCST AREA TODAY. WOULD
NOT BE SURPRISED TO SEE A FEW SPINKLES TODAY...ESPECIALLY N OF PT
CONCEPTION WHERE MID LVL LIFT WL BE GREATEST. HWVR...BLV FEW IF ANY
LOCATIONS WL RECEIVE MEASURABLE AMTS...SO WL REFRAIN FROM ADDING POPS.
MDLS ARE NOW IN RELATIVELY GOOD AGREEMENT WITH THE UPR LVL PATTERN
OVER THE NEXT 48 HRS...BUT HAVE DIFFERENCES WITH RESPECT TO TIMING.
CURRENT UPR LOW OFF THE CNTRL CA CST WL LIFT NEWD AND WKN LATER TODAY
AND TONIGHT...KICKED NEWD BY A STRONG NEGATIVELY TILTED UPSTREAM TROUGH
MOVING THRU THE ERN PAC. S/WV ENERGY DROPPING SWD FROM THE GULF OF
ALASKA WL HELP THE SYSTEM DEVELOP INTO A RATHER STRONG CUTOFF LOW
TONIGHT...WITH A POSITION NEAR 38N/132W BY EARLY SAT A.M.. AHEAD OF
THIS DVLPG SYSTEM...SOME WK S/WV RIDGING WL DVLP ACRS THE FCST AREA
TONIGHT/EARLY SAT...AND ONSHR GRADS WL ACTUALLY WKN A BIT. THIS MAY
HELP TO LIMIT STRATUS ACRS THE FCST AREA TONIGHT/SAT A.M.. THE 06Z
ETA SUPPORTS THIS IDEA BY SHOWING RELATIVELY LTL IN THE WAY OF MSTR
AT 950 MB ACRS THE FCST AREA TONIGHT...MAINLY CONFINED TO AREAS N OF
PT CONCEPTION. WITH A DECENT AMT OF MSTR IN THE H8 THRU H5 LYR TONIGHT
AND SAT...XPCT OCNL HIGH CLDS TO PUSH ACRS THE FCST AREA. WL PROBABLY
GO WITH PTLY CLDY SKIES IN MOST ZONES FOR TONIGHT/SAT...WITH SOME
PATCHY NIGHT THRU MORNING FOG. WITH LTL CHANGE IN THICKNESSES THRU
SAT...XPCT TEMPS BOTH DAYS TO BE SIMILAR TO THE READINGS ON THU.
00Z ETA WAS SLGTLY SLOWER THAN THE AVN WITH THE UPR LOW APCHG THE CST
SAT NIGHT/SUNDAY A.M....AND THE 06Z ETA HAS TRENDED ABT 6 HRS SLOWER
WITH THE SYSTEM...WIDENING THE GAP BETWEEN THE MODELS. WITH THE
TENDENCY FOR THE MDLS TO BE TOO FAST IN MOVING UPR LOWS EWD...AND
SINCE THE ETA HAS BEEN THE MORE CONSISTENT MODEL WITH THIS PARTICULAR
SYSTEM...HAVE DECIDED TO GO WITH ITS SLOWER SOLN. INCRGLY STRONG AND
MOIST SWLY FLOW FROM H85 THRU H5...IMPROVING MID LVL DYNAMICS AND A
NICE DIFLUENT UPR HEIGHT PATTERN WL BRING A GOOD CHANCE OF RAIN TO THE
CNTRL CST BY LATE SAT NIGHT. HAVE BUMPED POPS UPWARD IN ALL AREAS
SAT NIGHT...BUT LATER SHIFTS MAY NEED TO INCRS THEM TO LIKELY ACRS
SLO AND SBA COUNTIES. HAVE PUSHED POPS INTO THE LIKELY CATEGORY FOR
ALL ZONES ON SUNDAY AS THE UPR LOW MOVES ACRS NRN SXNS OF THE FCST
AREA. SNOW LVLS WL PROBABLY START OUT ARD 7000 FT SAT NIGHT...THEN
LOWER TO BETWEEN 5000 AND 6000 FEET ON SUN...AND POSSIBLY LOWER
DEPENDING UPON THE EXACT TRACK OF THE COLD UPR LVL CENTER. MOST OF
THE PRECIP MAY END BY AFTERNOON ACRS THE CENTRAL CST AS NWLY FLOW
AND SUBSIDENCE ON THE WRN SIDE OF THE SYSTEM SPRDS INTO THE AREA...
BUT THE THREAT OF RAIN WL CONT INTO SUN NIGHT ELSEWHERE.
ANOTHER S/WV DROPPING SEWD INTO THE FCST AREA ON MON WL BRING A SMALL
THREAT OF ADDITIONAL SHOWER ACTIVITY ACRS THE CNTRL CST AND IN THE
MTNS AS LOW AND MID LVLS REMAIN RATHER MOIST...BUT NWLY FLOW SHOULD
PRECLUDE ANY SHOWER ACTIVITY IN CSTL AND VLY ZONES S OF PT CONCEPTION.
THEN...UPR RIDGING SHOULD BUILD INTO THE AREA BY THE MIDDLE OF NEXT
WEEK FOR DRIER AND MUCH WARMER CONDITIONS.
LAX 000. BRUNO
.LOX...NONE.