MESOSCALE PRECIPITATION DISCUSSION 0080
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
326 PM EST FRI MAR 11 2016
 
AREAS AFFECTED...PORTIONS OF CENTRAL AND SOUTHERN CA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 112030Z - 120200Z
 
SUMMARY...RESIDUAL MOISTURE AHEAD OF AN APPROACHING FRONT COULD
RESULT IN A LOCALIZED FLASH FLOOD THREAT INTO EARLY
EVENING...ESPECIALLY ACROSS SOUTH FACING TERRAIN AND OVER BURN
SCARS.

DISCUSSION...MOISTURE ON THE NORTHERN END OF A WEAKENING
ATMOSPHERIC RIVER (IN THE FORM OF A 1.00 INCH PRECIPITABLE WATER
PLUME...PER THE LATEST BLENDED TPW IMAGES) CONTINUES TO SPREAD
INLAND ACROSS PORTIONS OF CENTRAL AND SOUTHERN CA AHEAD OF AN
APPROACHING COLD FRONT. ELEVATED INSTABILITY (IN THE FORM OF
MUCAPE OF 250 J/KG) IS PRESENT IN THE FLOW OFF THE CENTRAL CA
COAST...THOUGH NO LIGHTNING ACTIVITY HAS BEEN NOTED. BOTH REGIONAL
RADARS AND THE LATEST MRMS PRECIPITATION RATE PRODUCTS INDICATED
HOURLY RAINFALL RATES BETWEEN 0.25 AND 0.50 INCHES. SURFACE
OBSERVATIONS INDICATE THAT HOURLY RATES WERE CLOSER TO THE LOWER
END OF THE RANGE.

AS THE THRUST OF THE MOISTURE PLUME COMES ASHORE ACROSS SOUTHERN
AND CENTRAL CA AHEAD OF THE COLD FRONT...HOURLY RAINFALL RATES
COULD INCREASE CLOSER TO 0.50 INCHES...ESPECIALLY AS THE FLOW
BECOMES UPSLOPE ACROSS THE SOUTHERN SIERRA NEVADA RANGE. THE
LATEST HRRR/RAP SUGGEST THAT LOCAL 1.00 TO 1.25 INCH RAINFALL
AMOUNTS ARE POSSIBLE THROUGH 12/02Z...WITH THE HIGHEST AMOUNTS
ACROSS THE UPSLOPE AREAS.

THREE HOUR FLASH FLOOD GUIDANCE VALUES ACROSS THE SOUTHERN SIERRA
NEVADA RANGE ARE AS LOW AS 1.50 INCHES...SO LOCAL FLASH FLOOD
ISSUES ARE POSSIBLE HERE. ELSEWHERE...THE COMBINATION OF DEEPER
MOISTURE AND ELEVATED CONVECTION COULD RESULT IN LOCALIZED FLASH
FLOOD ISSUES...ESPECIALLY OVER THE TERRAIN AND BURN SCARS.

HAYES

ATTN...WFO...HNX...LOX...SGX...STO...

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

LAT...LON   37781970 37351898 36441852 35251816 34511784 
            34211767 33821774 33991835 34261982 34442038 
            35272093 35622055 35131963 34541857 34721845 
            35351873 35981908 36581954 37122012 37702048