MESOSCALE PRECIPITATION DISCUSSION 0119
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
227 PM EDT WED MAY 02 2018

AREAS AFFECTED...SOUTHWEST TO NORTHEAST KS...SOUTHEAST
NEB...NORTHWEST MO...SOUTHWEST TO SOUTH-CENTRAL IA

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

VALID 021825Z - 030025Z

SUMMARY...HEAVY SHOWERS AND THUNDERSTORMS ARE EXPECTED TO RAPIDLY
DEVELOP AND EXPAND NORTHEASTWARD IN COVERAGE THROUGH THE MID TO
LATE-AFTERNOON HOURS. SOME CONVECTIVE CELL TRAINING IS
LIKELY...AND THIS WILL ENCOURAGE SOME CONCERNS FOR FLASH FLOODING.

DISCUSSION...THE LATEST SURFACE ANALYSIS SHOWS A WELL-DEFINED
FRONT SITUATED FROM THE TX/OK PANHANDLE REGION NORTHEAST UP ACROSS
NORTH-CENTRAL KS AND INTO SOUTHWEST IA. ALONG AND SOUTH OF THIS
BOUNDARY...THE AIRMASS HAS BECOME QUITE UNSTABLE WITH MLCAPE
VALUES ON THE ORDER OF 2500 TO 3500 J/KG AND LI/S OF -8 TO -10.
ANY REMAINING CAPPING INVERSION ACROSS THE CENTRAL PLAINS IS
QUICKLY ERODING AS STRONG DIURNAL HEATING CONTINUES AND THE
INSTABILITY IS FURTHER BEING AIDED BY THE SOUTHERLY TRANSPORT OF A
MOIST BOUNDARY LAYER WITH SURFACE DEWPOINTS OF 65 TO 70 DEGREES
NOSING UP ACROSS CENTRAL/NORTHERN OK AND INTO SOUTHERN KS.

THE REGION THIS AFTERNOON WILL COME UNDER THE INFLUENCE OF A
RATHER STRONG UPPER TROUGH OVER THE FOUR CORNERS REGION WHICH IS
SLOWLY EJECTING EAST TOWARD THE HIGH PLAINS. VORT ENERGY EMBEDDED
WITHIN DEEP LAYER SOUTHWEST FLOW AHEAD OF THE TROUGH WILL BEGIN TO
INTERACT WITH THE FRONTAL ZONE AND THE VERY FAVORABLE
THERMODYNAMIC ENVIRONMENT FOR ORGANIZING CLUSTERS OF HEAVY SHOWERS
AND THUNDERSTORMS. THE CONVECTION SHOULD TRACK GENERALLY ALONG OR
JUST A TAD RIGHT OF THE MEAN 850/300 MB FLOW WHICH IS ORIENTED
NEARLY PARALLEL TO THE SURFACE FRONT IN A SW/NE FASHION. EXPECT AN
ENVIRONMENT AS A RESULT THAT IS CONDUCIVE FOR TRAINING CONVECTION
WHICH WILL ENHANCE RAINFALL POTENTIAL. LATER IN THE PERIOD TOWARD
EVENING...MORE ORGANIZED/MERGING CLUSTERS OF CONVECTION WILL TEND
TO ALLOW CONVECTION TO LIKELY BEGIN BOWING OFF TO THE EAST WHICH
MAY CONCENTRATE THE THREAT MORE ACROSS EASTERN KS AND THROUGH
WEST-CENTRAL MO. WPC IS FAVORING THE HRRR-EXP GUIDANCE IN THE
SHORT-TERM WHICH APPEARS TO ALREADY DOING WELL WITH SOME OF THE
CONVECTION INITIATING ACROSS SOUTHWEST KS.

RAINFALL RATES ARE LIKELY TO REACH AS HIGH AS 2.5 INCHES/HR GIVEN
THE DEGREE OF MID LEVEL MOISTURE CONCENTRATION COUPLED WITH THE
LOW LEVEL MOISTURE TRANSPORT/JET ENERGY IN PLACE AND ANTICIPATION
OF VERY STRONG UPDRAFT POTENTIAL GIVEN THE INSTABILITY PROFILES.
THE INITIAL FOCUS OF CONVECTION WILL BE MORE ACROSS CENTRAL AND
SOUTHWEST KS...BUT EXPECT CONVECTION TO ORGANIZE FARTHER NORTHEAST
NEAR AND TO THE EAST OF THE FRONT TOWARD EVENING WHICH WILL
INCLUDE NORTHEAST KS/NORTHWEST MO AND SOUTHWEST IA. SOME OF THESE
AREAS DID SEE SOME LOCALLY HEAVY RAINS LAST EVENING...AND SO THE
SOIL CONDITIONS ARE LOCALLY SOMEWHAT SENSITIVE HERE.

GIVEN THE TRAINING POTENTIAL...AND INTENSE RAINFALL RATES...STORM
TOTAL AMOUNTS THROUGH EARLY EVENING MAY REACH AS MUCH AS 3 TO 5
INCHES. SOME FLASH FLOODING WILL BE POSSIBLE.

ORRISON

ATTN...WFO...AMA...DDC...DMX...EAX...GID...ICT...OAX...OUN...
TOP...

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

LAT...LON   41419392 41269341 40919293 40439281 39669329
            39019430 38369545 37609707 37069860 36969954
            37020030 37290057 37930014 38839924 39829776
            40579635 40959555 41299461