MESOSCALE PRECIPITATION DISCUSSION 0498
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
524 PM EDT MON JUL 17 2017

AREAS AFFECTED...S-CNTRL NE INTO NRN/NWRN KS

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

VALID 172123Z - 180320Z

SUMMARY...TRAINING OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO
LEAD TO AN ELEVATED FLASH FLOOD THREAT FROM S-CNTRL NE INTO
NRN/NWRN KS THROUGH 03Z. RAINFALL RATES OF 1-2 IN/HR ARE LIKELY.

DISCUSSION...OVER THE PAST FEW HOURS...EXPERIMENTAL GOES 16 6.9
MICRON MOISTURE CHANNEL SHOWED A MID-LEVEL VORTICITY MAX SLOWLY
MOVING EAST ACROSS SWRN NEBRASKA. KUEX REFLECTIVITY SHOWED
THUNDERSTORMS HAVE BEEN INCREASING IN COVERAGE AND INTENSITY WITH
RADAR ESTIMATED RAIN RATES BETWEEN 1-2 IN/HR OVER DAWSON COUNTY.
MOVEMENT OF RAINFALL CORES HAS GENERALLY BEEN 10-20 KT TO THE
NORTH. GOES 16 EXPERIMENTAL TOTAL PRECIPITABLE WATER IMAGERY ALSO
INDICATED A NARROW SWATH OF HIGHER MOISTURE...1.6-1.8 INCHES
EXTENDING FROM SOUTH TO NORTH THROUGH WRN KS INTO THE ONGOING
CLUSTER OF THUNDERSTORMS...WHICH WAS IN LINE WITH RAP ANALYSES.
RAP ANALYSES ALSO AGREED WITH AREA VAD WIND PLOTS SHOWING SLIGHTLY
STRONGER SLY 850 MB FLOW...20-25 KT...WITHIN THIS NARROW MOISTURE
AXIS. THIS GIVES CONFIDENCE IN RECENT HRRR FORECASTS SHOWING HEAVY
RAINFALL POTENTIAL THIS EVENING.

SLOW MOVEMENT OF THE MID-LEVEL VORTICITY CENTER TO THE EAST IS
EXPECTED THROUGH 03Z WITH AN INCREASE IN 850 MB WINDS TO ABOUT 40
KT BY 03Z. THE INCREASING LOW LEVEL MOISTURE TRANSPORT INTO THE
SLOW MOVING CLUSTER OF CONVECTION IS EXPECTED TO ALLOW AN
INCREASING THREAT FOR TRAINING AND BACK BUILDING OF STORMS TOWARD
THE SOUTH THROUGH THE REMAINDER OF THE EVENING INTO THE EARLY
OVERNIGHT HOURS. A HEALTHY FIELD OF TCU IS ALREADY PRESENT OVER
PORTIONS OF N-CNTRL TO NWRN KS WHICH MAY BE A PRECURSOR TO
SUBSEQUENT CONVECTION. FLASH FLOOD GUIDANCE IS GENERALLY 2-3
INCHES IN 3 HOURS FROM SRN NE INTO NRN KS WHICH IS EXPECTED TO BE
MET IN A FEW LOCATIONS.

OTTO

ATTN...WFO...DDC...GID...GLD...ICT...LBF...

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

LAT...LON   41919866 41379833 40429851 38959890 38519960
            38930093 40770070 41570023 41889951