MESOSCALE PRECIPITATION DISCUSSION 0143
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
351 PM EDT MON MAY 14 2018

AREAS AFFECTED...NORTH-CENTRAL MISSOURI

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

VALID 141949Z - 150000Z

SUMMARY...FLASH FLOODING WILL BE POSSIBLE IN NORTH-CENTRAL
MISSOURI THIS AFTERNOON...ESPECIALLY ALONG AND JUST NORTH OF THE
I-70 CORRIDOR AS A LARGE CLUSTER OF THUNDERSTORMS PUSHES EAST.
RAIN RATES MAY APPROACH OR JUST EXCEED 2 IN/HR.

DISCUSSION...A VIGOROUS CONVECTIVE CLUSTER HAS BLOSSOMED OVER
NORTH-CENTRAL MISSOURI OVER THE PAST COUPLE HOURS WITH
CONSIDERABLE AMOUNTS OF LIGHTNING AND THE GOES-16 CONVECTION RGB
HIGHLIGHTING MANY SMALL ICE PARTICLES (INDICATIVE OF STRONG
CONVECTION). THIS CLUSTER APPEARED TO INITIATE OFF A LOW-LEVEL
CONVERGENCE AXIS WITH STRONGER SWLY FLOW OBSERVED TO THE
SOUTH...AND WEAKER WLY FLOW TO THE NORTH. THIS SHOULD HELP FOCUS
PROPAGATION OF THE MULTICELL CLUSTER AND FURTHER CELL DEVELOPMENT
TO THE EAST...AND THE LONG AXIS OF THE CLUSTER (AND CONVERGENCE
AXIS) WERE ROUGHLY ORIENTED WITH THE MEAN FLOW. RAP ANALYSIS SHOWS
MLCAPE AROUND 2000-2500 J/KG ON THE NOSE OF A SURFACE THETAE
AXIS...WITH EFFECTIVE DEEP LAYER SHEAR AROUND 30 KNOTS. THIS
SHOULD CONTINUE TO PROMOTE AN ORGANIZED CLUSTER OVER THE NEXT
SEVERAL HOURS. PRECIPITABLE WATER VALUES WERE AROUND 1.5 INCHES
PER CIRA BLENDED TPW AND RAP ANALYSIS...WHICH IS AROUND THE 90TH
PERCENTILE FOR MID MAY.

THE CONVECTIVE CLUSTER WAS SEPARATED INTO TWO PORTIONS...A FORWARD
PROPAGATING SEGMENT MOVING INTO WESTERN SALINE COUNTY AS OF
1940Z...AND A LARGER WING OF PRECEDING CONVECTION EXTENDING TO THE
EAST AHEAD OF THE NORTHERN END OF THAT LINE SEGMENT. THE
ORIENTATION OF THE LONG AXIS OF CONVECTION PARALLEL TO THE MEAN
FLOW SHOULD LEAD TO A SWATH ACROSS NORTH-CENTRAL MISSOURI WHERE
HEAVY RAIN WILL PERSIST FOR OVER AN HOUR. KEAX RADAR RAINFALL
ESTIMATES APPEAR TO BE SLIGHTLY HAIL CONTAMINATED... BUT MRMS
ESTIMATES WHICH ARE CONTROLLING FOR THAT TO A CERTAIN EXTENT STILL
SHOW RATES AS HIGH AS 2.0 TO 2.5 IN/HR. RAIN RATES APPROACHING 2
IN/HR COULD PRODUCE FLASH FLOODING...PARTICULARLY IF THEY WERE
SUSTAINED FOR 90 MINUTES OR MORE. ALTHOUGH FLASH FLOODING IS NOT
CERTAIN...THE POTENTIAL FOR TRAINING CONVECTION MEANS THAT
ISOLATED FLASH FLOODING SHOULD AT LEAST BE POSSIBLE OVER THE NEXT
SEVERAL HOURS (THROUGH 00Z).

LAMERS

ATTN...WFO...EAX...LSX...SGF...

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

LAT...LON   39929158 39579086 39029113 38629261 38549369
            38789413 39069413 39669319