MESOSCALE PRECIPITATION DISCUSSION 0259
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
724 PM EDT SAT AUG 09 2014
 
AREAS AFFECTED...WESTERN/SOUTHERN NE & NORTH-CENTRAL KS 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 092324Z - 100524Z
 
SUMMARY...A CONGEALING CONVECTIVE COMPLEX SHOULD MERGE BY 01Z
ACROSS WEST-CENTRAL AND SOUTHERN NE AND DROP SOUTHEAST INTO
NORTH-CENTRAL KS BY 06Z.  HOURLY RAIN RATES UP 2" AN HOUR COULD
CAUSE FLASH FLOODING.

DISCUSSION...AN OUTFLOW BOUNDARY SPARKED BY A HAIL-PRODUCING
THUNDERSTORM NEAR THEDFORD NE HAS SPURRED THE DEVELOPMENT OF
MULTIPLE INDIVIDUAL THUNDERSTORMS ACROSS WESTERN NE.  PRECIPITABLE
WATER VALUES OF 1.5-1.75" SUPPORT HOURLY RAIN RATES UP TO 2" AN
HOUR WITHIN THE THUNDERSTORMS, WHICH LOCAL RADARS APPEAR TO
CONFIRM.  TEMPERATURES AT 700 HPA ARE IN THE 9C RANGE, SO
MID-LEVEL CAPPING DOES NOT APPEAR TO BE IN PLAY WITH THIS AREA OF
STORMS.  MOST UNSTABLE CAPE VALUES OF 3000-4000 J/KG EXIST ACROSS
THE REGION, WHICH ARE ON THE HIGH END FOR THE WET MULTI-CELL
ENVIRONMENT, AND IMPLY EVENTUAL FORWARD PROPAGATION.

AS 850 HPA INFLOW INCREASES TOWARDS 20 KTS INTO A STATIONARY FRONT
AHEAD OF THE DEVELOPING COMPLEX, THE AVAILABLE CAPE AND INCREASING
FORWARD PROPAGATION OF THE COMPLEX COULD ALLOW FOR THE DEVELOPMENT
OF A WARM ADVECTION THUNDERSTORM BAND IN ADVANCE OF MAIN STORM
CLUSTER.  THESE DEVELOPMENTS SHOULD SHUT OFF INFLOW INTO A
LINGERING THUNDERSTORM BAND ACROSS EASTERN NE.  THE COMPLEX'S
EXPECTED FORWARD MOTION -- SOUTHEAST AT ~25 KTS -- COULD ALLOW IT
TO SHED PRECIPITATION OVER A FAIRLY SHORT TIME SCALE.  THE 18Z
SSEO NEIGHBORHOOD PROBABILITIES PEAK NEAR THE KS/NE BORDER IN THE
03-06Z PERIOD, WITH A 70%+ CHANCE OF EXCEEDING THREE HOURLY FLASH
FLOOD GUIDANCE VALUES DURING THAT TIME FRAME.  WITH HOURLY RAIN
RATES UP TO 2" AN HOUR AND THE MESOSCALE GUIDANCE SHOWING LOCAL
MAXIMA IN THE 3-5" RANGE NEAR THE NE/KS BORDER, FLASH FLOODING IS
CONSIDERED POSSIBLE WITHIN THIS REGION.

ROTH

ATTN...WFO...ICT...GID...LBF...GLD...BOU...CYS...

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

LAT...LON   40730211 41670281 42290258 42360139 41849982 40389795
            38979798 39710050 40730211