MESOSCALE PRECIPITATION DISCUSSION 0297
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
847 PM EDT TUE JUN 12 2018

AREAS AFFECTED...SW/SC KS...NW OK...OK/TX PANHANDLES

CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY

VALID 130046Z - 130545Z

SUMMARY...SCATTERED THUNDERSTORMS HAVE DEVELOPED ACROSS PORTIONS
OF THE SOUTHERN PLAINS...AND WERE DRIFTING VERY SLOWLY ACROSS THE
REGION. THESE STORMS SHOULD PRODUCE RAIN RATES AS HIGH AS 2-3
IN/HR...WHICH COULD LEAD TO FLASH FLOODING DESPITE ONGOING DROUGHT
CONDITIONS.

DISCUSSION...SOUTHERN PLAINS RADARS HAVE SHOWN SCATTERED
SUPERCELLS DEVELOPING IN A PRONOUNCED SURFACE TROUGH STRETCHING
FROM NEAR AMARILLO TX...TO NEAR DODGE CITY KS...TO NEAR SALINA KS.
SOME SUPERCELL SPLITS HAVE BEEN NOTED...LEADING TO A COMPLEX
VARIETY OF CELL MOTIONS AND MERGERS. THE MERGERS WERE OCCASIONALLY
LEADING TO EFFECTIVELY STALLING STORMS AND PROLONGED HEAVY
RAINFALL IN VERY CONCENTRATED AREAS. ADDITIONALLY...BUNKERS RIGHT
MOVING SUPERCELL MOTIONS ANALYZED BY THE RAP ARE ROUGHLY AT A
MINIMUM ALONG THE SURFACE TROUGH ALONG WHICH SUPERCELLS INITIATED
(AROUND 5 KNOTS OR LESS)...WHICH IS LEADING TO NEARLY STATIONARY
SUPERCELLS REGARDLESS OF MERGERS.

LOW-LEVEL MOISTURE WAS POOLED NEAR THE BOUNDARY...WITH 850MB
DEWPOINTS IN THE +16C TO +18C RANGE. THE 00Z DDC SOUNDING OBSERVED
A VALUE OF +17C WHICH IS CLOSE TO JUNE DAILY MAXIMUM VALUES IN THE
SITE SOUNDING HISTORY. ACCORDINGLY PRECIPITABLE WATER VALUES ARE
ALSO ELEVATED...AROUND 1.6 INCHES PER THE RAP ANALYSIS. THIS IS
VERY SUPPORTIVE OF HEAVY RAINFALL RATES IN SUPERCELLS...WHICH CAN
OFTEN PRODUCE HEAVIER RAIN RATES THAN WOULD OTHERWISE BE SUGGESTED
BY THE ENVIRONMENT. IN THIS CASE...2-3 IN/HR RAIN RATES SEEM
ACHIEVABLE...AND 2 IN/HR RAIN RATES HAVE ALREADY BEEN ESTIMATED BY
MRMS AND SOME OF THE REGIONAL RADAR DUAL POL ALGORITHMS. THESE
SHOULD BE SUFFICIENT TO PRODUCE FLASH FLOODING...PARTICULARLY IF
THEY ARE SUSTAINED IN A PARTICULAR AREA LONGER THAN AN
HOUR...WHICH IS POSSIBLE GIVEN THE POTENTIAL FOR 5 KNOT CELL
MOTIONS. ALTHOUGH THE FLASH FLOODING MAY NOT BE WIDESPREAD...GIVEN
THE ALREADY STATED FACTORS...AT LEAST ISOLATED FLASH FLOODING
APPEARS LIKELY TO OCCUR IN SOME PORTIONS OF THE OUTLINED AREA.

LAMERS

ATTN...WFO...AMA...DDC...ICT...OUN...PUB...

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

LAT...LON   38769911 38769809 37909806 36749853 35769961
            34980076 34860190 35260257 36070285 36960222
            38080042