Re: More rain?

AREA FORECAST DISCUSSION
FXUS66 KLOX 221213
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
400 AM PST TUE FEB 22 2005

...MORE OF THE SAME...PLUS THE ADDED POSSIBILITY OF SEVERE WEATHER...

.SHORT TERM...THE UPPER LEVEL STORM SYSTEM THAT HAS BEEN BATTERING CALIFORNIA FOR THE LAST WEEK IS LOCATE THIS MORNING ABOUT 140 NM WEST OF POINT CONCEPTION...RIGHT ABOUT WHERE WE EXPECTED IT TO BE. IN 24 HOURS...MODELS AGREE THAT THE STORM WILL BE LOCATED OVER THE CALIFORNIA BIGHT...MOVING TOWARDS THE COAST OF ORANGE COUNTY. THIS MEANS THAT THE SOUTHLAND WILL HAVE YET ANOTHER 24 TO 36 HOURS OF HEAVY DOWNPOURS...STRONG THUNDERSTORMS...HAIL...AND ANOTHER FOOT OR TWO OF SNOW IN THE MOUNTAINS.

RAINFALL OVERNIGHT WAS SHOWERY IN NATURE WITH SOME THUNDERSTORMS AND SMALL HAIL BEING REPORTED. THIS PROMPTED THE ISSUANCE OF SEVERAL FLASH FLOOD WARNINGS FOR AREAS ALONG THE COAST FROM SANTA BARBARA TO MALIBU. THESE RESULTED IN INCREASED MUD FLOWS AND THE CLOSURE OF MORE ROADWAYS. IN THE LAST 12 HOURS...RAINFALL AMOUNTS HAVE RANGED ONLY UP TO AROUND 1 AND A HALF INCHES...NOWHERE NEAR THE HALF A FOOT THAT WAS MEASURED SUNDAY NIGHT AND MONDAY MORNING. 24 HOUR RAINFALL TOTALS TOP OUT AT 2.5 INCHES IN THE SANTA BARBARA MOUNTAINS...TO NEAR 4 INCHES IN THE VENTURA MOUNTAINS...TO JUST UNDER 3 INCHES IN THE SAN GABRIEL MOUNTAINS OF LOS ANGELES COUNTY.


AS THE STORM SYSTEM APPROACHES THE CALIFORNIA BIGHT...WE SHOULD SEE BETTER DYNAMICS ALONG WITH COLDER TEMPERATURES ALOFT AND MORE UNSTABLE SURFACE CONDITIONS. MSAS LIFTED INDICES ARE NOW RUNNING -3 OFF THE COAST THIS MORNING AND THE GFS MODEL FORECAST LLS FOR 500 TEMPS OF -26 C. VANDENBERG TEMPS AT 500 MB WERE RUNNING -23 C AT 12Z THIS MORNING. ALL THESE ARE FAIRLY CLASSIC SEVERE WEATHER INDICATORS. THEREFORE...TODAY WE WILL BE MORE CONCERNED WITH THUNDERSTORMS WITH LOCALLY HEAVY DOWNPOURS...HAIL AND GUSTY WINDS.

SOME OF THESE STORMS COULD APPROACH SEVERE LEVELS LATER TODAY WITH DAMAGING WINDS...LARGE HAIL AND WATERSPOUTS OVER THE COASTAL WATERS...CHANGING TO SMALL TORNADOS AS THEY MOVE ONSHORE. COASTAL COMMUNITIES FROM SANTA BARBARA TO THE ORANGE COUNTY BORDER NEED TO KEEP AN EYE ON THE SKIES TODAY...ESPECIALLY THIS AFTERNOON AND EARLY EVENING HOURS.

THE LATEST SATELLITE AND RADAR DATA SHOWS MULTIPLE BANDS OF SHOWERS WITH EMBEDDED THUNDERSTORMS THROUGHOUT THE REGION FROM THE ORANGE COUNTY BOUNDARY ALL THE WAY UP TO HEARST CASTLE. EACH OF THESE HAS THE POTENTIAL FOR LOCALLY HEAVY DOWNPOURS...GUSTY WINDS AND SMALL HAIL. OF MAJOR CONCERN IS THE REGION OF STORMS NOW ENTERING RADAR COVERAGE SOUTH OF POINT CONCEPTION. THIS BAND IS EXPECTED TO HIT HARD ALONG THE SOUTH FACING SLOPES OF SANTA BARBARA AND VENTURA COUNTY WITHIN THE NEXT SEVERAL HOURS...INCREASING THE THREAT FOR EVEN MORE MUD SLIDES AND FLOODING DURING THE MORNING HOURS.

SIMILAR BANDS ARE EXPECTED TO CONTINUE TO RE-DEVELOP OVER THE NEXT 24 HOURS AS THE LOW CONTINUES TO SPIN OFF OUR SHORES. IN ADDITION... THUNDERSTORMS ARE EXPECTED TO LINGER OVER THE REGION INTO WEDNESDAY SINCE THE LOW WILL LINGER JUST TO THE EAST OF THE REGION THROUGH THURSDAY. NEED TO KEEP AN EYE OUT FOR POSSIBLE WRAP-AROUND MOISTURE IN THE DESERTS AS THE LOW EXITS. RIGHT NOW...THE FORECAST DOES NOT INCLUDE THIS POSSIBILITY.

EXTENDED...MODEL AGREEMENT IS VERY GOOD THROUGH THE EXTENDED PERIOD. WE ARE CALLING FOR DRY CONDITIONS THURSDAY THROUGH SUNDAY...BUT THE LOW LINGERS TO THE EAST OF US THROUGH FRIDAY AND CYCLONIC FLOW STAYS OVER THE REGION...THEREFORE WE SHOULD SEE SOME UNSETTLED CONDITIONS WITH A VERY SLIM CHANCE FOR PRECIPITATION. THEREFORE...ADDED SOME 10 PERCENT POPS INTO THE FORECASTS FOR THURSDAY AND FRIDAY. ON SATURDAY...A WEAK RIDGE BUILDS INTO THE REGION...PERHAPS GIVING US A FAIR WEATHER DAY. ON SUNDAY LOOK FOR SHOWERS TO CREEP BACK INTO THE FORECAST AS YET ANOTHER LOW BEGINS TO TAKE UP RESIDENCE OFF THE CENTRAL COAST OF CALIFORNIA BY TUESDAY MORNING. THE LONGER RANGED MODELS HAVE THIS SYSTEM MOVING DIRECTLY THROUGH CENTRAL AND SOUTHERN CALIFORNIA NEXT TUESDAY AND WEDNESDAY. THIS IS QUITE A WAYS OUT... BUT WITH THE WAY THIS SEASON IS GOING...WE WILL NEED TO KEEP AN EYE OUT FOR IT.



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.LOX WATCHES/WARNINGS/ADVISORIES...

FLOOD WATCH (SEE LAXFFALOX).

SEVERE THUNDERSTORM WARNING (SEE LAXSVRLOX).

WINTER STORM WARNING (SEE LAXWSWLOX).

MARINE WEATHER STATEMENT (SEE LAXMWSLOX).

SMALL CRAFT ADVISORY (SEE LAXCWFLOX).



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DANIELSON