MESOSCALE PRECIPITATION DISCUSSION 0462
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
822 PM EDT MON JUL 10 2017

AREAS AFFECTED...CENTRAL IL...NORTHERN & CENTRAL IND...WESTERN OH

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

VALID 110020Z - 110530Z

SUMMARY...POTENTIAL FOR FLASH FLOODING AS CONVECTIVE CELLS
ORGANIZE AND ISENTROPIC WAA ASCENT REGIME TAKES OVER.  

DISCUSSION...STRONG INSTABILITY WITH 2000-4500 J/KG OF MLCAPE FROM
NW OH TO WEST CENTRAL IL AND SUFFICIENT LOW LEVEL CONVERGENCE HAS
SPARKED STRONG CONVECTIVE CELLS ALONG/AHEAD OF THE COLD FRONT IN W
IL AND IN PROXIMITY OF THE WARM FRONT ACROSS N IND TOWARD NW OH. 
SOME OF THE CLUSTERS ARE BEGINNING TO GROW UPSCALE WITH EXPANSION
OF STORMS TOWARD CLUSTERS WITH POTENTIALLY A FEW SMALL MCS
STRUCTURES DEVELOPING AFTER 00Z.

GOES-16 WV AND VISIBLE LOOP DEPICT LARGER SCALE FORCING ASSOCIATED
WITH A DIGGING SHORTWAVE OVER CENTRAL WI WITH A RELATIVELY FLAT
EXTENSION OF ENERGY ACROSS S LK MI.  THIS COUPLED WITH AN EXITING
60-70KT 3H JET STREAK OVER SE MI ATTM SUPPORTS STRONGER FORCING
AND SYNOPTIC ASCENT PATTERN FOR THE CONVECTION NEAR THE WARM FRONT
OVER NE IND/NW OH AS WELL AS NEAR A WEAK NW-SE PRESSURE TROF FROM
NEAR RZL TO SW OF MIE. STRONGER WSW LLJ OF 30-35KTS SHOULD
CONTINUE TO SUPPORT STRONG MST FLUX AND INCREASING RAINFALL
EFFICIENCY FOR CONVECTION AND GIVEN PRIOR ROUND OF CONVECTION LAST
EVENING...GROUND CONDITIONS ARE A BIT MORE COMPROMISED AND
SUSCEPTIBLE TO FLASH FLOODING.  HOWEVER...FLOODING POTENTIAL IS
CURRENTLY CONDITIONAL GIVEN THE UPSTREAM DEVELOPMENT WHICH HAS THE
POTENTIAL FOR UNDERCUTTING THE BEST MST FLUX/INSTABILITY TO EACH
COMPLEX.  THIS IS IN LINE WITH RECENT HRRR AND RAP MODEL
SOLUTIONS.

FURTHER WEST IN CENTRAL IL...GUIDANCE HAS BEEN UNDER-PERFORMING
THE STRENGTH/COVERAGE THAT IS CURRENTLY EVOLVING NEAR PIA. THE
STRONGER INSTABILITY (DEVELOPING COLD POOL) AND PROXIMITY TO THE
500-1000MB THICKNESS RIDGE SUPPORTS STRONGER SOUTHWARD AND
EVENTUALLY SOUTHWESTWARD PROPAGATION VECTORS FEEDING OFF UPSTREAM
INSTABILITY. HOWEVER...WITHOUT PROXIMITY FROM BEST UPPER LEVEL
SUPPORT/FORCING LLJ IS LIKELY TO BE A BIT WEAKER AS WELL AS
VEERING WITH TIME MEANING A DECREASED WAA REGIME AND EVENTUALLY
TOWARD CAA.  THIS LEADS TO A LOWER POTENTIAL FOR TRAINING/SLOW
CELL MOTIONS AND GIVEN HIGHER FFG IN THE VICINITY THERE MAY BE
LESS POTENTIAL FOR FF AS WELL.  STILL IN THE SHORT-TERM FF THREAT
IS NON-ZERO GIVEN THE STRONGER CELLS WITHIN FAVORABLE LOW LEVEL
INFLOW ENVIRONMENT WITH TPWS OVER 1.75".  THIS HAS THE POTENTIAL
FOR RATES OVER 2" AND THEREFORE A SWATH OF 2-3" TOTALS. 

GALLINA

ATTN...WFO...CLE...ILN...ILX...IND...IWX...LOT...

ATTN...RFC...NCRFC...OHRFC...

LAT...LON   41408514 41158322 40168318 39738417 39498744
            39408898 39588970 39819026 40319035 40659010
            40868967 40788925 40638875 40618796 40638741
            40968697 41178640