MESOSCALE PRECIPITATION DISCUSSION 0648
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
435 PM EDT MON AUG 07 2017

AREAS AFFECTED...CENTRAL/EASTERN NV

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 072035Z - 080235Z

SUMMARY...SCATTERED CLUSTERS OF SLOW-MOVING SHOWERS AND
THUNDERSTORMS ARE EXPECTED THROUGH THE AFTERNOON AND INTO THE
EVENING HOURS. SOME POCKETS OF FLASH FLOODING ARE POSSIBLE.

DISCUSSION...GOES-WEST VIS/IR SATELLITE IMAGERY IS SHOWING AN
EXPANSION OF CONVECTIVE TOPS OVER PORTIONS OF CENTRAL AND EASTERN
NV AS A WEAKENING UPPER LOW AND A DEFORMATION AXIS ALOFT WORK IN
TANDEM WITH STRONG DIURNAL HEATING AND A POOL OF PWATS THAT ARE
1.5 TO 2 SIGMAS ABOVE NORMAL.

SO FURTHER EXPANSION OF CONVECTION IS EXPECTED THIS AFTERNOON AND
INTO THE EVENING HOURS WITH GENERALLY SLOW CELL MOTIONS AS WEAKLY
DIFFLUENT FLOW ALOFT AND ADDITIONAL DIURNAL HEATING COMMENCES.
RAINFALL RATES OF UP TO 1 TO 1.5 INCHES/HR ARE EXPECTED...AND SOME
SMALLER SCALE CELL-MERGER ACTIVITY WILL BE POSSIBLE AS WELL WHICH
COULD CONTRIBUTE TO A FURTHER ENHANCEMENT OF RAINFALL RATES. THE
SLOW CELL MOTION IN PARTICULAR IS WHAT WILL TEND TO DRIVE THE
FLASH FLOOD THREAT AT LEAST LOCALLY.

THE LATEST 12Z HIRES MODEL CONSENSUS SUPPORTS AS MUCH AS 2 INCHES
OF RAIN...AND THIS WILL BE ENOUGH TO CAUSE AT LEAST SOME FLASH
FLOODING CONCERNS AND ESPECIALLY GIVEN THE SHORT-TERM NATURE OF
THE AMOUNTS.

ORRISON

ATTN...WFO...BOI...LKN...VEF...

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

LAT...LON   42031578 41911508 41721444 40911411 39531411
            38551443 37781537 37691626 37981686 38401732
            38981765 39431745 39771702 40261674 40911680
            41441711 41851703 42011666