MESOSCALE PRECIPITATION DISCUSSION 0002
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1116 AM EST TUE JAN 05 2016
 
AREAS AFFECTED...SOUTHERN CA 
 
CONCERNING...HEAVY RAINFALL 
 
VALID 051615Z - 060015Z
 
SUMMARY...THE WARM CONVEYOR BELT OF A CYCLONE IS EXPECTED TO
SLOWLY MOVE THROUGH SOUTHERN CA TODAY, WITH HOURLY RAIN RATES UP
TO 0.7" AND LOCAL AMOUNTS NEAR 3" EXPECTED.

DISCUSSION...WATER VAPOR IMAGERY DEPICTS AN UPPER LEVEL VORTICITY
MAXIMUM NEAR 34N 124W WHICH IS APPROACHING THE CA COAST.  AHEAD OF
THIS FEATURE, 850 HPA INFLOW OF 30-40 KTS IS MOVING INTO THE
REGION NEAR THE CYCLONE'S WARM CONVEYOR BELT, WHICH CAN BE
CLASSIFIED AS A WEAK ATMOSPHERIC RIVER PER AN SAB/NESDIS BRIEFING.
 MUCAPES OF 250+ J/KG LIE JUST OFFSHORE PER THE MOST RECENT SPC
MESOANALYSIS, WHICH IS ALLOWING CONVECTION TO BUILD PER COOLING
CLOUD TOPS IN RECENT IR SATELLITE IMAGERY.  PRECIPITABLE WATER
VALUES ONSHORE ARE NEAR 1" PER GPS VALUES, AND UP TO 1.25"
OFFSHORE, WHICH IS 2-2.5 SIGMAS ABOVE THE MEAN FOR EARLY JANUARY. 
RECENT RAINFALL MESONETS INDICATE HOURLY RAIN RATES UP TO 0.6"
NORTHWEST OF SANTA BARBARA EARLIER THIS MORNING.

THE EXPECTATION IS FOR HEAVY RAINFALL TO SLOWLY WORK DOWN THE
COAST OF SOUTHERN CA, WITH THE BULK OF THE RAINFALL SHIFTING SOUTH
OF THE CA/BAJA CA BORDER AROUND 00Z, WITH SLIGHTLY INCREASING
PRECIPITABLE WATER VALUES DURING THE DAY TODAY.  THE CAM GUIDANCE
INDICATE LOCAL AMOUNTS OF ~3" ARE EXPECTED WITH THIS SYSTEM.  THIS
USUALLY TRANSLATES TO HOURLY RAIN RATES PEAKING AROUND 0.7", WITH
THE AVAILABLE INSTABILITY AUGMENTING THE MODEST LOW-LEVEL INFLOW. 
FLOOD CONCERNS WOULD BE HIGHEST WITHIN URBAN AREAS AND PLACES
WHERE BURN SCARS EXIST.

ROTH

ATTN...WFO...HNX...LOX...PSR...SGX...VEF...

ATTN...RFC...CBRFC...CNRFC...

LAT...LON   35732044 35582001 35201936 34791851 34711821 
            34721735 34471654 33831549 33061482 33261544 
            33941660 33521622 33391624 33101627 32781609 
            32641620 32501702 32641746 33431792 33411815 
            33341825 32921829 32771848 33071932 33281968 
            33712020 34282070 34652065