MESOSCALE PRECIPITATION DISCUSSION 0377
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1143 PM EDT WED JUN 22 2016
 
AREAS AFFECTED...E ILLINOIS...INDIANA...OHIO...EXT N KENTUCKY...N
WEST VIRGINIA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 230345Z - 230945Z
 
SUMMARY...MATURING MCS CONTINUES TO PROGRESS SE WITH ISOLATED
FLASH FLOODING REMAINING POSSIBLE ESPECIALLY ON UPSTREAM SW EDGE
OF COMPLEX.

DISCUSSION...WV/IR LOOP INDICATES MATURING MCS JUST EAST OF THE
APEX IN THE RIDGE WITH SOME DIFFLUENCE DUE TO THE SPLITTING FLOW
NEAR/AHEAD OF S/W EXITING N MN. STRENGTHENING UPPER LEVEL JET TO
OVER 110KTS WILL TRACK ACROSS NY/NEW ENGLAND ALLOWING FOR
ADDITIONAL UVV DIVERGENCE IN RIGHT ENTRANCE AS IT PROGRESSES
ACROSS OH TOWARD PA/WV BY 10Z.   THIS SUPPORTS A SURFACE WAVE IN
NE IL ATTM WITH MAIN FRONTAL ZONE BISECTING IND INTO N KY/SW OH
ATTM THAT WILL PROGRESS E THRU IND AND W CENT OH PROVIDING A GOOD
MST CONVERGENCE/UPGLIDE IN ADVANCE OF THE LOW ACROSS OH INTO
WV...AS SEEN BY INCREASING SHOWER/CONVECTIVE COVERAGE IN RADAR
MOSAIC ATTM.  GIVEN TPWS NEAR 2.0" AND MODERATE FLUX...RATES ALONG
THIS DEEPER MST CONVERGENCE SHOULD SUPPORT HIGH RATES NEAR 2"/HR
GENERALLY IN LINE WITH RADAR ESTIMATES AND GUAGES ACROSS N IND/NW
OH.  SOME SLIGHT UPTICK WITH STRENGTHENING LLJ MAY SUPPORT HIGHER
TOTALS BUT FORWARD PROPAGATION MAY LIMIT OVERALL TOTALS LEADING TO
ISOLATED AREAS OF FFG EXCEEDANCE...MORE ON THE SHORTER TERM SIDE. 
THIS INCREASES THE THREAT WHERE VALUES ARE LOWER IN WV LATER IN
THE TIME PERIOD. 

STRENGTHENING AND VEERING LOW LEVEL JET TO 60KTS FROM SW TO NEAR W
AND PROXIMITY TO DIFFLUENCE REGION ALOFT SHOULD SUPPORT CONTINUED
UPSTREAM DEVELOPMENT ALONG THE COLD FRONT WSW OF THE SURFACE LOW
ACROSS E IL INTO W CENTRAL IN.  STRONGER MST AND INSTABILITY FLUX
SHOULD SUPPORT STRONGER CONVECTIVE GROWTH AT THIS INTERFACE WITH
RATES UP TO AND EXCEEDING 2"/HR LEADING TO GREATEST POTENTIAL FOR
FLASH FLOODING IN THIS VICINITY.  THIS FF THREAT WOULD BE EVEN
GREATER IF THE LINE ALIGNS WITH NW-SE LINE OF LOWERED FFG FROM
MCLEAN/CHAMPAIGN IL COUNTIES TO DECATUR IND COUNTY...THOUGH
CURRENT RADAR/IR TRENDS AND 12C 7H CAP SEEMS TO SUPPORT AT LEAST
LINE OF COUNTIES NORTH APPEARS MORE LIKELY A TRACK AT THIS TIME.

ADDITIONALLY...THIS LINE ACROSS E IL/W CENT IN IS LIKELY TO
OBSTRUCT BEST FLUX TO CELLS DIRECTLY N AND E OF THE SURFACE WAVE
POTENTIALLY LEADING TO A GAP OF REDUCED TOTALS BETWEEN THE TWO
BEST ZONES OF PRECIPITATION AS SUGGESTED BY RECENT OPERATIONAL,
EXPERIMENTAL AND PARALLEL HRRR RUNS.  

GALLINA

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

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

LAT...LON   41668614 41488325 40068099 39027953 38258047 
            38758248 38958524 40028855 40998935 41198707