MESOSCALE PRECIPITATION DISCUSSION 0445
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
513 PM EDT FRI JUL 13 2018

AREAS AFFECTED...SOUTHWEST UT...SOUTHEAST NV...EXT NORTHWEST AZ

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

VALID 132115Z - 140200Z

SUMMARY...DEVELOPMENT OF SLOW MOVING COMPLEX.

DISCUSSION...ICX RADAR DEPICTS CLUSTER OF CELLS IN NW GARFIELD
COUNTY HAS LAID DOWN A SOLID OUTFLOW BOUNDARY THAT APPEARS TO BE
SPARKING NEW DEVELOPMENT WITH BROADER/STRONGER UPDRAFTS.  SFC
OBSERVATIONS AND RAP ANALYSIS DEPICT A NARROW RIBBON OF MST POOLED
THROUGH THE VIRGIN RIVER VALLEY WITH SBCAPES TO 1500 J/KG ACROSS
SW UT.  PROPAGATION VECTORS WILL SUPPORT SLOW SOUTH AND
SOUTHWESTWARD PROGRESS TOWARD THE BETTER INSTABILITY THROUGH THE
EVENING.  OVERALL MOISTURE IS REDUCING WITH TIME BUT STILL IS
ANALYZED IN THE 1.25-1.5" RANGE SUPPORTING EFFICIENT RAINFALL
PROCESSES AND RATES UP TO 1.5"/HR WITH LOCALIZED TOTALS OF 1-1.25"
POSSIBLE AS UPDRAFTS WILL REMAIN STATIONARY GIVEN MEAN FLOW EVEN
AS THE OUTFLOW PRESSES SOUTHEAST WITH THE MAJORITY OF THE RAINFALL
FALLING IN LESS THAN AN HOUR.  AS SUCH FLASH FLOODING IS POSSIBLE
ALONG AND SOUTH OF THE TRACK.   

OTHER CELLS IN THE CLOVER MOUNTAINS WILL SUPPORT SOUTHWARD OUTFLOW
BOUNDARY/NEW DEVELOPMENT AS WELL WITH THE POTENTIAL OF CELL
MERGERS INCREASING THE LOCALIZED THREAT FOR FLASH FLOODING AT THE
COLLISION INTERSECTIONS. 

GALLINA

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

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

LAT...LON   38491393 38301349 38291208 37471168 36931215
            36551330 36551440 37311508 37891504 38351465