Graphic for MPD #0502
MESOSCALE PRECIPITATION DISCUSSION 0502
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1120 PM EDT MON JUL 17 2017

AREAS AFFECTED...SOUTH CENTRAL NEB...NORTH CENTRAL KS

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

VALID 180320Z - 180800Z

SUMMARY...CONTINUED FLASH FLOODING THREAT OVER AREAS ALREADY
IMPACTED EARLIER TONIGHT AS NEW DEVELOPMENT FILLS IN UPSTREAM.

DISCUSSION...RADAR MOSAIC DENOTES OVERALL WANING MCS AS MAIN
FORWARD PROPAGATING OUTFLOW TO THE SE IS NARROW STABLE AREA (AND
AREA OF REDUCED MOISTURE PER GOES-16 TPW PRODUCT) OVER E KS. 
STILL THE OUTFLOW BOUNDARY DOES ARC BACK TOWARD THE WEST LAID OUT
E-W AND GENERALLY PERPENDICULAR TO THE STRENGTHENING LLJ THAT RUNS
FROM DDC TOWARD S CENTRAL NEB.  RAP/GOES TPW ANALYSIS COMBINED
WITH 00Z RAOBS FROM THE VICINITY SHOW THIS NARROW CORRIDOR OF
INCREASED MOISTURE ACROSS WEST CENTRAL KS TOWARD THE MEAN
SHORTWAVE LOCATION NEAR CUSTER COUNTY. NEB.  AS SUCH INCREASED
NEAR BOUNDARY LAYER CONVERGENCE ALONG THIS OUTFLOW HAS SEEN A
RECENT UPTICK IN CONVECTIVE ACTIVITY/IR COOLING/LIGHTNING
STRIKES...AND GIVEN ORIENATION TO THE MCV SHIFTING EAST AND THE
MEAN MESOSCALE SHORTWAVE IN CUSTER COUNTY...CELL MOTIONS ARE NEAR
ZERO FOR THIS LOCATION...POSING AT LEAST A SLIGHT CHANCE FOR 2-3"
TOTALS GIVEN RATES OF 1.5-2"/HR WITH SOME INCREASED CHANCE OF
BACKBUILDING GIVEN THE CONTINUED CONVERGENCE ALONG THE BOUNDARY.

FURTHER NORTH...THE STRENGTHENED REAR INFLOW JET TO THE MCV IS
ALSO LIGHTING UP GIVEN STRONGER MST CONVERGENCE AROUND 7H...AND
WHILE THE CONVECTION IS A BIT MORE ELEVATED...THERE REMAINS
SUFFICIENT MOISTURE AND INSTABILITY ADVECTED ON THE ASCENDING LLJ
TO SUPPORT CONTINUED UPSTREAM REDEVELOPMENT ALONG THIS BOUNDARY AS
WELL.  WHILE A BIT LESS EFFICIENT THE SUB-CLOUD ENVIRONMENT
REMAINS FAIRLY SATURATED ALLOWING FOR RATES OF 1.5-2"/HR.  GIVEN
THIS IS FALLING OVER AREAS HIGHLY AFFECTED BY 3-4" THIS SHOULD AT
LEAST PROLONG ANY ONGOING FLOODING CONCERNS IN THE VICINITY
THROUGH THE NEXT FEW HOURS.  

BIGGEST REMAINING UNCERTAINTY IS THE DURATION AT WHICH CONVECTION
WILL MAINTAIN...BUT GIVEN DDC VWP AND RAP ANALYSIS SUGGESTING
35-40KT LLJ MAINTAIN WITH SLIGHT VEERING THROUGH 07-08Z THERE
REMAINS A THREAT THOUGH GIVEN REDUCING INSTABILITY WITH
TIME...CELLS ARE LIKELY TO BECOME A BIT LESS ORGANIZED AND
SCATTERED IN NATURE WITH MORE ISOLATED SMALLER POCKETS OF FLASH
FLOOD INDUCING RAINFALL TOTALS.

GALLINA

ATTN...WFO...GID...GLD...LBF...TOP...

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

LAT...LON   41529863 41189745 39779771 39299880 39190006
            39440062 40450007 41260002


Last Updated: 1120 PM EDT MON JUL 17 2017