MESOSCALE PRECIPITATION DISCUSSION 0577
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1204 AM EDT FRI OCT 16 2015
 
AREAS AFFECTED...SOUTHEAST CALIFORNIA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 160400Z - 160800Z
 
SUMMARY...ADDITIONAL SHOWERS AND THUNDERSTORMS WITH LOCALLY HEAVY
RAINFALL RATES WILL PERSIST OVER THE NEXT FEW HOURS. FLASH FLOOD
WILL REMAIN LOCALLY POSSIBLE.

DISCUSSION...IR/WV SATELLITE IMAGERY SHOWS A WELL-DEFINED UPPER
LOW MOVING GRADUALLY NORTH INTO CENTRAL PORTIONS OF
CALIFORNIA...AND THIS CONTINUES TO INTERACT WITH AN ANOMALOUSLY
MOIST AIRMASS FOR LOCALLY HEAVY SHOWERS AND THUNDERSTORMS.
INSTABILITY PARAMETERS ARE QUITE MODEST...WITH MUCAPE VALUES
GENERALLY AT OR BELOW 500 J/KG...BUT THERE IS SUFFICIENT LARGER
SCALE ASCENT ASSOCIATED WITH THE UPPER LOW TO SUSTAIN CONVECTIVE
DEVELOPMENT.

THE ANOMALOUS MOISTURE PROFILES ARE RUNNING ON THE ORDER OF 3 TO 4
SIGMAS ABOVE THE MEAN FOR THIS TIME OF THE YEAR...AND WITH EARLIER
CONVECTION...THIS HAS HELPED CONTRIBUTE TO RAINFALL RATES OF 0.5"
TO 1.0" PER HOUR. SOME CELLS OVER SOUTHEAST CALIFORNIA HAVE TENDED
TO REPEAT OVER THE SAME AREA GIVEN RATHER UNIDIRECTIONAL DEEP
LAYER FLOW OVER THE REGION.

OVER THE NEXT FEW HOURS...SOME ADDITIONAL CONVECTIVE DEVELOPMENT
IS LIKELY AND WHILE WIDESPREAD FLASH FLOODING IS NOT
EXPECTED...THERE WILL BE LOCALIZED CONCERNS FOR RUNOFF PROBLEMS
AND SOME FLASH FLOODING. ADDITIONAL RAINFALL AMOUNTS OF UP TO 1 TO
2 INCHES WILL BE POSSIBLE UNDERNEATH SOME OF THE STRONGER
CONVECTIVE CORES.

ORRISON

ATTN...WFO...PSR...SGX...VEF...

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

LAT...LON   36201632 34961500 33691447 32661464 32641535 
            32911580 34091668 34851709 35861707