MESOSCALE PRECIPITATION DISCUSSION 0389
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
326 PM EDT SUN JUL 26 2015
 
AREAS AFFECTED...NORTHEAST CO & NEIGHBORING PORTIONS OF NE/KS 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 261926Z - 270126Z
 
SUMMARY...THUNDERSTORMS HAVE BEGUN TO DEVELOP ACROSS EAST-CENTRAL
CO.  HOURLY RAIN RATES UP TO 1.5" COULD CAUSE FLASH FLOODING.

DISCUSSION...A SHARP TROUGH AT 850 HPA, WITH UPSLOPE FLOW TO ITS
NORTH, WAS REVEALED BY RECENT VAD WIND PROFILES.  A COUPLE WEAK
SHORTWAVES ALOFT ARE MOVING THROUGH THE INTERIOR WEST AT THE
PRESENT TIME.  PRECIPITABLE WATER VALUES IN THE REGION ARE CLOSE
TO 1.25".  MLCAPES NEAR THE STORMS ARE 2000 J/KG, WHILE LOW-LEVEL
INFLOW REMAINS FAIRLY WEAK, ON THE ORDER OF 15 KTS.  STORMS ARE
CURRENTLY MIGRATING TOWARDS AREAS OF GREATER INSTABILITY, WHICH IS
KEEPING THEM ON THE MOVE TO THE NORTHEAST AT 15-20 KTS.  RECENT
RAP GUIDANCE INDICATES A WEAKNESS IN THE CAP ACROSS NORTHEAST CO,
SO DO NOT EXPECT IT TO BE A HINDRANCE TO LATER ACTIVITY.  CIN
ACROSS THE REGION HAS VIRTUALLY ERODED.

THE RAP GUIDANCE INDICATES A SLOW INCREASE IN LOW-LEVEL INFLOW
ACROSS THE REGION INTO THE EVENING HOURS, WHICH SHOULD HELP
ORGANIZE WET MULTICELL CLUSTERS.  MLCAPES CONTINUE TO BUILD
BETWEEN NOW AND THEN, FORECAST TO REACH 3000-4000 J/KG ACROSS
SOUTHEAST CO AND SOUTHWEST KS BY THE END OF THE PERIOD.  BOTH THE
06Z AND 12Z SSEO NEIGHBORHOOD PROBABILITIES OF EXCEEDING THREE
HOUR FLASH FLOOD GUIDANCE VALUES RISE UNTIL 00Z, INDICATING AN
INCREASING THREAT OF FLASH FLOODING OVER THE NEXT SEVERAL HOURS. 
STORM MOTION TO THE NORTHEAST AT 15-20 KTS SHOULD CONTINUE AS IT
IS SUPPORTED BY THE MEAN 850-400 HPA WIND AND FORWARD PROPAGATING
CONVECTIVE VECTORS, THOUGH INCREASING INSTABILITY TO THE SOUTH AND
INCREASING INFLOW MAY LEAD TO SOME BACKBUILDING.  OVERALL, CELL
TRAINING IS CONSIDERED THE MAIN FLASH FLOOD THREAT.  STORM MOTION
SHOULD HELP INCREASE CLOUD BASE INFLOW LOCALLY, LEADING TO GREATER
ORGANIZATION.  BELIEVE THE 12Z NMMB OR A NORTHWARD ADJUSTED 12Z
NAM CONEST HAVE THE BEST IDEAS THIS AFTERNOON FOR CONVECTIVE
PLACEMENT.  THE MESOSCALE GUIDANCE SHOWS LOCAL AMOUNTS IN THE 2"
RANGE, WHICH COULD FALL QUICKLY, AS THE AVAILABLE MOISTURE
SUPPORTS HOURLY RAIN RATES UP TO 1.5".  FLASH FLOOD GUIDANCE
VALUES ARE LOW IN THIS AREA.

ROTH

ATTN...WFO...BOU...GLD...LBF...PUB...

ATTN...RFC...ABRFC...MBRFC...

LAT...LON   40980196 40360107 39900129 39490202 39010329 
            38390515 39220533 40070468 40390429 40880332