MESOSCALE PRECIPITATION DISCUSSION 0067
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1035 AM EDT SAT MAY 09 2015
 
AREAS AFFECTED...EASTERN CO, SOUTHEAST WY, & SOUTHWEST NE 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 091433Z - 092033Z
 
SUMMARY...THUNDERSTORMS WITH HEAVY RAINFALL OVER THE PAST NINE
HOURS HAVE HAD OBSERVED RAINFALL RATES UP TO 1.5" AN HOUR.  WITHIN
AN AREA OF SATURATED SOILS AND LOW FLASH FLOOD GUIDANCE, FLASH
FLOODING IS CONSIDERED LIKELY.

DISCUSSION...A MOIST FLOW EAST OF AN UPPER LOW IN THE SOUTHWEST US
HAS LED TO SEVERAL HOURS OF THUNDERSTORM ACTIVITY AND SATURATED
SOUNDINGS.  ALTHOUGH THE PRECIPITABLE WATER VALUES IN THE REGION
ARE ON THE ORDER OF 0.75" -- THEY LIE BETWEEN THE 75TH AND 95TH
PERCENTILES FOR EARLY MAY.  THE FLOW IS UNIDIRECTIONAL OUT OF THE
SOUTH.  TRAINING BANDS OF THUNDERSTORMS HAVE OCCASIONALLY SET UP,
LEADING TO HIGH RAINFALL RATES, WITH 1.5" AN HOUR OBSERVED AND
ESTIMATED BY LOCAL RADARS IN EASTERN CO.

RECENT RAP/NAM/GFS FORECASTS INDICATE THE POOL OF 500+ J/KG CAPE
ACROSS SOUTHEAST AND EAST-CENTRAL CO AS WELL AS KS IS EXPECTED TO
GROW TODAY WITHIN THE SYSTEM'S INVADING DRY SLOT.  FLOW ACROSS THE
REGION IS EXPECTED TO TAKE ON A MORE UPSLOPE COMPONENT DURING THE
DAY TODAY.  THE 06Z SSEO NEIGHBORHOOD PROBABILITIES SHOW THE FLASH
FLOOD THREAT GROWING WITH TIME ACROSS NORTHEAST CO AND ADJACENT
SOUTHEAST WY, PEAKING DURING THE EARLY TO MID AFTERNOON HOURS. 
DUE TO RECENT RAINS AND TOPOGRAPHY, FLASH FLOOD GUIDANCE VALUES
ARE LOW IN THIS REGION.  THE MESOSCALE GUIDANCE GENERALLY
ADVERTISES 1.5-2" OF RAIN OVER THE NEXT SEVERAL HOURS IN THIS
REGION.  CONSIDERING THE ONGOING FLASH FLOOD EVENT, RAINFALL RATES
OF 1.5" IN TRAINING BANDS, AND POSSIBILITY OF IT GROWING IN SCALE,
FLASH FLOODING IS CONSIDERED LIKELY.

ROTH

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

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

LAT...LON   41900458 41770288 41410250 40270257 38860338 
            38190508 38940561 40050581 41090578 41650550