MESOSCALE PRECIPITATION DISCUSSION 0593
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
930 PM EDT MON AUG 22 2016
 
AREAS AFFECTED...EASTERN CA...SOUTHERN NV...SOUTHWEST
UT...NORTHWEST AZ 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 230125Z - 230500Z
 
SUMMARY...SOME ADDITIONAL EXPANSION OF THUNDERSTORMS ARE EXPECTED
THIS EVENING. SLOW MOVEMENT AND HEAVY RAINFALL RATES WILL FOSTER
ADDITIONAL FLASH FLOODING CONCERNS.

DISCUSSION...GOES-14 SRSOR VISIBLE IMAGERY SHOWS SOME IMPRESSIVE
CONVECTIVE TOWERS GOING UP OVER PORTIONS OF FAR EASTERN CA NEAR
NEEDLES...AND ALSO OVER SOUTHERN NV TO THE NORTH OF LAS VEGAS. THE
PROXIMITY OF A WEAK MID LEVEL VORTICITY CENTER EMBEDDED WITHIN A
BROAD TROUGH AXIS IS ACTING AS A FOCUS FOR THUNDERSTORMS TO EXPAND
IN COVERAGE.

PWATS ARE LOCALLY AS HIGH AS 1.25 INCHES AND MLCAPE VALUES ARE AS
HIGH AS 1000 TO 1500 J/KG...AND THIS IS SUFFICIENT FOR SUSTAINABLE
CONVECTION WITH HEAVY RAINFALL RATES THAT MAY REACH AS HIGH AS 1.5
INCHES/HR.

CONDITIONS WILL IMPROVE LATER THIS EVENING WITH THE LOSS OF
DAYTIME HEATING...BUT OVER THE NEXT FEW HOURS...EXPECT ADDITIONAL
SLOW-MOVING THUNDERSTORMS WITH HEAVY RAIN. THIS WILL BE ESPECIALLY
BE THE CASE WITH ANY CELL-MERGER ACTIVITY WHICH WILL BE POSSIBLE.
AREAS OF SOUTHERN NV NEAR AND NORTH OF LAS VEGAS ARE SEEING SOME
OF THE GREATEST INSTABILITY POOLED...AND SO SOME OF THE HEAVIEST
RAINFALL POTENTIAL WILL EXIST OVER THESE AREAS.

RAINFALL AMOUNTS OF 2 TO 4 INCHES ARE GOING TO BE POSSIBLE THROUGH
THE EVENING HOURS...AND THIS WILL ENHANCE THE THREAT FOR RUNOFF
AND/OR FLASH FLOODING PROBLEMS.

ORRISON

ATTN...WFO...FGZ...PSR...SLC...VEF...

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

LAT...LON   38251370 38041326 37601293 36941305 36341316 
            35561336 34631344 34211429 34251541 34511628 
            35401677 36291655 36871611 37361543 38121454