MESOSCALE PRECIPITATION DISCUSSION 0559
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
911 PM EDT MON OCT 05 2015
 
AREAS AFFECTED...PORTIONS OF THE SOUTHWEST 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 060111Z - 060411Z
 
SUMMARY...CONVECTION CONTINUES TO BLOSSOM ACROSS SOUTHERN CA,
SOUTHERN NV, NORTHWEST AZ, AND SOUTHWEST UT.  WITH HOURLY RAIN
RATES UP TO 1" POSSIBLE, FLASH FLOODING AND DEBRIS FLOWS REMAIN
POSSIBLE.

DISCUSSION...PER THE 2254Z SPENES MESSAGE, A SHORTWAVE ROTATING
AROUND THE SOUTHEAST SIDE OF THE UPPER LOW IN SOUTHERN CA IS
ENHANCING CONVECTION NEAR THE BORDER JUNCTION OF NV/AZ/UT. 
SEVERAL FLASH FLOOD WARNINGS HAVE BEEN RECENTLY ISSUED IN THIS
REGION.  NEAR THE UPPER LOW ITSELF, CONVECTION IS BEGINNING TO
CONCENTRATE.  CONVERGENT INFLOW AT 700 HPA REMAINS 15-30 KTS OUT
OF THE SOUTH TO THE EAST OF THE UPPER LOW.  MLCAPES ARE IN THE
500-1500 J/KG RANGE PER SPC MESOANALYSES AND THE 00Z VEF/LAS VEGAS
SOUNDING.  PRECIPITABLE WATER VALUES ARE IN THE 0.9-1.1" RANGE PER
GPS VALUES.  RADAR ESTIMATES SHOW A BROAD AREA OF 0.50-1" OF RAIN
ACROSS SOUTHERN NV, WITH SPOTTY AMOUNTS IN THE 2" RANGE.

THE CAM GUIDANCE INDICATES THAT LOCAL AMOUNTS OF 1" ARE POSSIBLE
OVER THE NEXT FEW HOURS, WHICH SEEMS TOO LOW GIVEN THE FAVORABLE
MOISTURE, INFLOW, INSTABILITY, INCOMING SHORTWAVE, AND RECENT
CLOUD COOLING ON INFRARED SATELLITE IMAGERY.  HOURLY RAIN RATES UP
TO 1", WITH LOCAL AMOUNTS UP TO 2", COULD CAUSE FLASH
FLOODING/DEBRIS FLOWS IN A NORMALLY ARID REGION.

ROTH

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

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

LAT...LON   37501494 37381329 36221304 35291376 34811390 
            34311386 34181401 33811580 34091662 34671767 
            35371788 35981776 35911742 36301752 36401754 
            36801732 36971633 37491516