MESOSCALE PRECIPITATION DISCUSSION 0194
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
623 PM EDT THU MAY 24 2018

AREAS AFFECTED...EASTERN KS...WESTERN MO...NORTHWEST AR...FAR
NORTHEAST OK

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

VALID 242219Z - 250219Z

SUMMARY...SLOW MOVING CONVECTION DEVELOPING IN A HIGH MOISTURE
ENVIRONMENT WILL POSE A FLASH FLOOD THREAT INTO THE LATE
AFTERNOON/EARLY EVENING.

DISCUSSION...REGIONAL RADARS ACROSS EASTERN KS/NORTHWEST AR INTO
SOUTHWEST MO SHOWED A GENERAL INCREASE IN CONVECTIVE COVERAGE THIS
AFTERNOON. THE STORMS WERE DEVELOPING IN AN AXIS OF 1000-2000 J/KG
OF MLCAPE...WITH THE HIGHEST VALUES ACROSS EASTERN KS. THE GOES-16
IR LOOP SHOWED STRENGTHENING CELLS...WITH CLOUD TOP TEMPERATURES
NEAR -65 CELSIUS.

THE MOST RECENT RAP ANALYSIS AND BLENDED TPW PRODUCT SHOWED AN
AXIS OF 1.75 INCH PRECIPITABLE WATER AIR (WHICH IS ABOUT TWO
STANDARD DEVIATIONS ABOVE THE MEAN) NEARLY COINCIDENT WITH THE
INSTABILITY AXIS. THE SCATTERED CONVECTION THAT HAS DEVELOPED IN
THE DEEP MOISTURE HAS PRODUCED HOURLY RAINFALL RATES BETWEEN
1.75/2.00 INCHES OVER PORTIONS OF EASTERN KS (BASE DON THE KTOP
RADAR)...THOUGH MESONET OBSERVATIONS WERE NOT QUITE THIS HIGH. IT
IS POSSIBLE THAT THESE RAINFALL AMOUNTS ARE HAIL CONTAMINATED...AS
THE KTOP HCA PRODUCT INDICATED THE PRESENCE OF HAIL...WHICH IS
SUPPORTED BY THE PRESENCE OF DRY AIR IN THE MID LEVELS...PER RAP
SOUNDINGS.

AHEAD OF A WEAK SHORT WAVE IN THE MID LEVEL FLOW...THE 850-300 MB
MEAN WINDS ARE 10 KNOT OR LESS THROUGH 25/02Z...ESPECIALLY OVER
PORTIONS OF FAR EASTERN KS AND WESTERN MO. THE WEAK FLOW COULD
CONTINUE TO PROMOTE HOURLY RAINFALL RATES NEAR 2.00 INCHES, WITH
THE POTENTIAL OF UP TO 3.00 INCHES IN 2 HOURS OR LESS, AS DEPICTED
FROM THE LATEST HIGH-RES CAM GUIDANCE (INCLUDING RECENT HRRR AND
EXPERIMENTAL HRRR RUNS).
GIVEN THE FFG VALUES, THESE AMOUNTS WILL POSE A LOCALIZED FLASH
FLOOD THREAT THROUGH 01-02Z.

THE LIMITING FACTOR FOR A MORE WIDESPREAD FLASH FLOOD THREAT WOULD
BE CONVECTIVE COVERAGE. MOST OF THE HIGH RESOLUTION GUIDANCE
DEPICTS THE CONVECTION AS MOSTLY SCATTERED...WHICH WOULD FAVOR OF
A LOCALIZED FLASH FLOOD THREAT. AFTER 25/01Z...DWINDLING
INSTABILITY SHOULD ALLOW THE FLASH FLOOD THREAT TO WANE.

HAYES/HURLEY

ATTN...WFO...EAX...ICT...LZK...SGF...TOP...TSA...

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

LAT...LON   39219573 38879428 36709229 35619303 35949446
            37159647 37839696 38679674