SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
AFDLOX 950 PM PST SAT FEB 24 2001
MODEL COMPARISONS SEEM TO SUGGEST THAT THE AVN MODEL CONTINUES TO
HANDLE TIMING AND MOVEMENT OF CURRENT PACIFIC STORM SYSTEM BETTER THAN
ETA.
SYNOPTIC SITUATION...IN THE NEXT 24 HRS...UPPER LOW 100 NM WEST OF CAPE
MENDOCINO WILL DRIFT S TO OFFSHORE CEN CA AND FRONTAL BAND OVER SRN CA
WILL BECOME STATIONARY AND PIVOT...BECOMING MORE NE-SW ORIENTED...BUT
STILL LINGERING OVR SRN CA. IN 48 HRS...UPPER LOW MOVES INTO THE CA
BIGHT AND PASSES S OF SAN DIEGO. SIGNIFICANT MOISTURE CONTINUES TO WRAP
AROUND THE LOW THROUGH EARLY TUESDAY.
RADAR SHOWS MOST SHOWERS NOW OVER VEN AND LA COUNTIES...EXTENDING
ONSHORE OVER THE CA BIGHT. THESE SHOWERS CONTINUE TO MOVE ONSHORE FROM
VEN S TO THE MEXICAN BORDER. TO THE WEST...ONLY SCATTERED LIGHT SHOWERS
ARE SHOWING UP OVER SBA AND SLO COUNTIES. BASED ON THE RADAR AND ON THE
NEW AVN MODEL...CUT BACK OR ELIMINATED THE HEAVY RAIN WORDING IN THE
ZONE UPDATE ISSUED AT 845 PM.
SATELLITE IMAGERY SHOWS A WIDE CLOUD BAND COVERING MUCH OF SRN CA AND
EXTENDING OFFSHORE TO THE WEST AND SOUTHWEST. VERY DIFFICULT TO PICK UP
ON WHERE THE SURFACE FRONT IS OFFSHORE DUE TO THE HIGH CLOUD COVER.
THIS BAND SEEMS TO BE IN THE INITIAL STAGES OF WAVE DEVELOPMENT IN
RESPONSE BOTH TO THE UPPER LOW OFF CST OF NRN CA...AND AN APPROACHING
JET STREAK. A BIT CONCERNED THAT THIS BAND MAY BRING HEAVIER SHOWERS
BACK TO SLO AND SBA COUNTIES BEFORE THE NIGHT IS OVER...BUT SOME OF
THIS ENHANCED CLOUD COVER HAS ALREADY PASSED OVER THE VBX RADAR WITH
NO ASSOCIATED SHOWER ACTIVITY. SO WHAT WE SEE IS LITTLE CORRELATION
BETWEEN THE RADAR AND THE SATELLITE...A CONFLICTING SITUATION.
NOTE THAT A PACJET AIRCRAFT IS AIRBORNE AT THIS TIME. THEY ARE
CURRENTLY NEAR 123 W 32 N...UNDER THE APPARENT BAROCLINIC LEAF. THEY
ARE REPORTING NW WINDS...WITH NOTHING ON RADAR 200KM WEST OF THEIR
POSITION. THEY ALSO REPORT THAT SFC PRESSURE HAS BEEN GRADUALLY RISING
...WHICH WOULD BE INCONSISTENT WITH CYCLOGENESIS UNDER THE APPARENT
BAROCLINIC LEAF. FROM THIS REPORT IT LOOKS LIKE CUTTING BACK ON THE
POPS OVR SLO AND SBA COUNTY WAS THE WAY TO GO.
ATTM...WE ARE STILL HOLDING ON TO THE MENTION OF LOCALLY HEAVY RAINS
AND SNOWS VEN CO EASTWARD. THIS IS CONSISTENT WITH THE AVN MODEL. THE
WINTER STORM WARNING SEEMS TO BE VERIFYING QUITE WELL WITH SNOW REPORTS
OF 8 INCHES SO FAR...BUT THE SNOW LEVELS HAVE BEEN RISING RAPIDLY THIS
EVENING...UP TO ABOUT 6000 FT ATTM...AND EXPECTED TO HOLD THERE.
EARLIER WE CANCELED A FLOOD ADVISORY DUE TO THE RAINS SLACKING OFF.
NOTE THAT THE GOOD FOLKS AT SAN DIEGO HAVE ISSUED A FLASH FLOOD WATCH
FOR THEIR MOUNTAINS. THIS LOOKS GOOD TO US AND IS CONSISTENT WITH THE
AVN. WE CONSIDERED ISSUING ONE FOR VEN AND LA COUNTIES...BUT HAVE HELD
OFF DUE TO DOWNWARD TREND IN THE RAIN AMOUNTS IN OUR AREAS TONIGHT AND
THE UNCERTAINTY OF EXACTLY WHERE THE HEAVY RAIN WILL FINALLY LINE UP
TOMORROW. HOWEVER...ALL SHOULD KEEP TUNED FOR THE POSSIBILITY OF AN
ISSUANCE LATER TONIGHT OR EARLY TOMORROW IF CONDITIONS WARRANT.
WITH LOW LINGERING INTO MONDAY AND LOTS OF LOW LEVEL MOISTURE...WILL
HOLD ON TO THE CHANCE OF SHOWERS EVERYWHERE THROUGH MONDAY.
EXTENDED...MEDIUM RANGE MODELS IN FAIR AGREEMENT. UPPER LOW LINGERS
INTO WED BEFORE DEPARTING...WITH THE CHANCE OF SHOWERS LINGERING INTO
EARLY WED S OF PT CONCEPTION AND OVER THE MTS AND DESERTS. THUR SHOULD
BE PARTLY CLOUDY...BUT A NEW SYSTEM MOVES INTO THE CEN COAST ON FRIDAY
WITH THE CHANCE FOR SHOWERS MOVING SE THRU THE DAY. LOOKS LIKE CLOUDY
AND COOL WITH A CHANCE OF SHOWERS TO START OFF NEXT WEEKEND.
LAX ++86. DANIELSON
.LAX...WINTER STORM WARNING...SEE LAXWSWLAX.
SMALL CRAFT ADVISORY...SEE LAXCWFLAX.