MESOSCALE PRECIPITATION DISCUSSION 0516
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
846 PM EDT SUN JUL 22 2018

AREAS AFFECTED...EASTERN CA & CENTRAL NV & VICINITY

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

VALID 230044Z - 230524Z

SUMMARY...THUNDERSTORMS CONTINUE TO BROADEN IN COVERAGE ACROSS THE
TERRAIN OF EASTERN CA AND CENTRAL NV.  HOURLY RAIN RATES TO 1.5"
ARE EXPECTED UNTIL ACTIVITY WANES AROUND 05Z.

DISCUSSION...ANOTHER DAY OF AFTERNOON/ EVENING THUNDERSTORM
ACTIVITY IS BEING WITNESSED ACROSS THE TOPOGRAPHY OF EASTERN AND
NORTHERN CA AS WELL AS THE WRINKLED TOPOGRAPHY OF THE GREAT BASIN
DESERT TODAY, WITH VAD WIND PROFILES SHOWING A 700 HPA TROUGH IN
ROUGHLY THE SAME PLACE AS PREVIOUS DAYS WHICH IS TRYING TO FOCUS
SOME OF THE ACTIVITY, WITH THE MOUNTAINS FOCUSING THE STORMS
ACROSS NORTHERN AND EASTERN CA.  ACTIVITY IS BEING AIDED BY
DIVERGENCE ALOFT BEING AFFORDED BY A BRANCH OF THE SUBTROPICAL JET
AIMING TOWARDS THE CENTRAL SIERRA NEVADA AND THE MAIN BELT OF THE
WESTERLIES CLOSEBY TO THE NORTH.  PRECIPITABLE WATER VALUES REMAIN
QUITE HIGH, IN THE 0.8-1" RANGE ACROSS NV AND AROUND 0.5" IN THE
HIGH SIERRA.  ML CAPE VALUES ARE 500-1500 J/KG.  CIN IS JUST
BEGINNING TO SET IN, BUT AS OF YET HAS NOT AFFECTED CONVECTIVE
COVERAGE.

THE MESOSCALE GUIDANCE CONTINUES TO LACK UTILITY FOR QPF IN THIS
REGION.  RAP GUIDANCE SUGGESTS THAT ACTIVITY IN NV SHOULD SETTLE
SOMEWHAT SOUTHWARD IN CONCERT WITH THE 700 HPA TROUGH.  UNLESS AN
UPPER LEVEL SHORTWAVE CAN SHARPEN ACROSS THE REGION IN THE
MEANTIME, THUNDERSTORMS ARE EXPECTED TO PERSIST FOR ANOTHER FEW
HOURS BEFORE FADING AROUND 05Z ONCE CIN FULLY ENVELOPS THE REGION.
 IN THE MEANTIME, THE AVAILABLE MOISTURE AND INSTABILITY SUPPORTS
HOURLY RAIN TOTALS TO 1.5", WHICH WOULD BE PROBLEMATIC NEAR ANY
WASHES/ARROYOS, BURN SCARS, AND TOWNS WITHIN THE REGION. 

ROTH

ATTN...WFO...EKA...HNX...LKN...MFR...REV...SLC...STO...VEF...

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

LAT...LON   41922253 41832114 40821969 40841809 41141564
            40461454 38481324 37391444 36961664 36941682
            35891811 36161862 37921997 39372071 40612160
            41242300