MESOSCALE PRECIPITATION DISCUSSION 0323
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
356 PM EDT TUE JUL 07 2015
 
AREAS AFFECTED...NORTHEAST CA, NORTHWEST NV, SOUTHWEST NV 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 071955Z - 080125Z
 
SUMMARY...THUNDERSTORMS ARE FORMING WITHIN AN ANOMALOUSLY MOIST
AIRMASS.  WITH HOURLY RAINFALL RATES OF 1" POSSIBLE, FLASH
FLOODING IS A CONCERN, PARTICULARLY NEAR BURN SCARS.

DISCUSSION...RECENT SATELLITE AND RADAR IMAGERY SHOW THUNDERSTORM
DEVELOPMENT ACROSS EAST-CENTRAL CA, SOUTHWEST OR, AND PORTIONS OF
CENTRAL NV.  THE NV ACTIVITY WAS IN ASSOCIATION WITH A LOW-LEVEL
CIRCULATION.  PRECIPITABLE WATER VALUES ARE CLOSE TO 1", CLOSE TO
THREE SIGMAS ABOVE THE NORM FOR EARLY JULY.  MIXED LAYER CAPES OF
500-1000 J/KG EXIST HERE, WITH CIN ERODING ACROSS THE REGION PER
RECENT SPC MESOANALYSES.

SOME LOCATIONS WITHIN THIS AREA EXPERIENCED HEAVY RAINFALL/FLASH
FLOODING YESTERDAY.  THE FLOW ACROSS NORTHEAST CA IS
UNIDIRECTIONAL WITH HEIGHT FROM THE SOUTH-SOUTHEAST, WHICH COULD
LEAD TO CELL TRAINING.  STORM MOTIONS TO THE NORTH-NORTHWEST ARE
EXPECTED PER THE MEAN 850-400 HPA WIND.  RECENT RAP GUIDANCE SHOWS
MUCAPES INCREASING OVER THE NEXT SEVERAL HOURS TOWARDS THE 2000
J/KG RANGE, WHICH SHOULD LEAD TO AN EXPANSION OF THUNDERSTORMS
ACROSS THE REGION.  THE MESOSCALE GUIDANCE SHOWS LOCAL AMOUNTS IN
THE 1-2" RANGE ACROSS WESTERN NV, NORTHEAST CA, AND SOUTHWEST OR. 
FLASH FLOODING, PERHAPS IN THE FORM OF DEBRIS FLOWS, IS POSSIBLE
ACROSS THIS RUGGED REGION, PARTICULARLY NEAR BURN SCARS.

ROTH

ATTN...WFO...BOI...EKA...HNX...LKN...MFR...PDT...PQR...REV...
STO...

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

LAT...LON   44082201 43752118 42671986 41811771 41631765 
            39701645 38641681 38811812 37791848 37741947 
            38782049 39792137 40472193 40952256 40782300 
            41122362 41492366 42462347 43072301 43842262