MESOSCALE PRECIPITATION DISCUSSION 0207...CORRECTED
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
302 PM EDT SUN MAY 27 2018

CORRECTED FOR GRAPHIC

AREAS AFFECTED...SOUTHEAST AND CENTRAL WYOMING

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

VALID 271850Z - 272350Z

SUMMARY...WITH A SLOW-MOVING CLOSED LOW TO THE WEST AND ANOMALOUS
MOISTURE IN PLACE, CONDITIONS WILL REMAIN FAVORABLE FOR
SLOW-MOVING CONVECTION.  ADDITIONAL HEAVY AMOUNTS ARE POSSIBLE
THIS AFTERNOON.

DISCUSSION...LOW LEVEL SOUTHEASTERLY TO EASTERLY FLOW EAST OF A
CLOSED LOW CENTERED OVER THE GREAT SALT LAKE BASIN IS SUPPORTING
ANOMALOUS PWS ACROSS MUCH OF WYOMING EARLY THIS AFTERNOON...WITH
THE GFS INDICATING A FURTHER INCREASE TO 2-3 STANDARD DEVIATIONS
ABOVE NORMAL ACROSS MUCH OF THE REGION BY THE LATE AFTERNOON. 
THIS MOISTURE WILL CONTINUE TO INTERACT WITH A SERIES OF MID-UPPER
LEVEL SHORTWAVES EMBEDDED WITHIN DIFFLUENT FLOW AHEAD OF THE LOW. 
THIS ALONG WITH AMPLE INSTABILITY WILL CONTINUE TO SUPPORT
DEVELOPING CONVECTION WITH TRAINING CELLS.  THIS MAY PRODUCE
LOCALLY HEAVY AMOUNTS..ESPECIALLY ACROSS OROGRAPHICALLY FAVORED
REGIONS.  LATEST RUNS OF THE OPERATIONAL AND EXPERIMENTAL HRRR ARE
LESS BULLISH, HOWEVER FOR THE 6-HR PERIOD ENDING 00Z MON, THE 12Z
RUNS OF THE HWR-ARW, HRW-NMMB AND NSSL-WRF ALL SHOW LOCALLY HEAVY
AMOUNTS OF AN INCH OR MORE ACROSS PORTIONS OF THE UPSLOPE TERRAIN
FROM THE LARAMIE AND SHIRLEY MOUNTAINS IN THE SOUTHEAST TO THE
WIND RIVER AND ABSAROKA RANGES IN CENTRAL WYOMING.  THE 12Z HREF
NEIGHBORHOOD PROBABILITIES SHOW A SIGNIFICANT THREAT FOR AMOUNTS
OF 2-INCHES OR MORE NEAR THE RATTLESNAKE HILLS AND SOUTHERN
PORTIONS OF THE WIND RIVER RANGE DURING THIS PERIOD.  WET
ANTECEDENT CONDITIONS WILL HEIGHTEN THE THREAT FOR FLASH FLOODING
ACROSS PORTIONS OF THE REGION.

PEREIRA

ATTN...WFO...CYS...RIW...

ATTN...RFC...CBRFC...MBRFC...

LAT...LON   44190946 44150834 43680706 43060535 42020474
            41500488 41250530 41370602 41770654 42000721
            42450765 42030799 42070843 42620878 42980878
            43490954