MESOSCALE PRECIPITATION DISCUSSION 0184
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
252 AM EDT MON JUN 08 2015
 
AREAS AFFECTED...SOUTHERN ILLINOIS...SOUTHEASTERN
MISSOURI...WESTERN KENTUCKY 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 080651Z - 081251Z
 
SUMMARY...SUBTLE INFLECTION POINT ALONG SQUALL LINE MAY CONTINUE
TO LEAD TO LOCALIZED MAXIMA OF RAINFALL TOTALS AS THE LINE DROPS
SOUTH.

DISCUSSION...OUTFLOW DOMINATED SQUALL LINE CONTINUES TO DROP SOUTH
ACROSS MISSOURI/SOUTHERN ILLINOIS.  ALONG THE LINE A SMALL
INFLECTION/WAVE AS A BIT OF INCREASED DEEP MOISTURE
CONVERGENCE...AND IS MOVING SOUTH-SOUTHWEST ALONG THE INSTABILITY
AXIS PER RAP ANALYSIS FIELDS.  IT IS WITHIN THIS AXIS THAT MLCAPES
TO 2500 J/KG AND ENHANCED TOTAL PWATS IN EXCESS OF 1.5" ARE
AVAILABLE FOR CONTINUED HIGHLY EFFICIENT RATES IN EXCESS OF
2-2.5"/HR MAKING TOTALS VERY NEAR 1HR FLASH FLOOD GUIDANCE VALUES
IN THE AREA.  WITH EXCELLENT DIFFLUENCE ALOFT SEEN IN WV AND
ANALYSIS FIELDS...GOOD EVACUATION OF THESE DEEP CORES ALSO
SUPPORTS A WIDE STRATIFORM REGION WITH MODERATELY HIGH RATES TO
COMPOUND RAINFALL TOTALS AND POSSIBLE FLASH FLOODING.

RADAR LOOP SHOWS CELL/MCS PROPAGATION VECTORS TO BE CONVERGENT AT
NEARLY THE SAME LOCATION AS THE INFLECTION/INTERSECTION WITH THE
INSTABILITY AXIS...ALLOWING FOR MERGERS IN A VERY NARROW BAND OF
HIGHEST LOCALIZED TOTALS TO BE ORIENTED WELL WITH I-57 AS IT DROPS
SOUTH.  RECENT UPTICK OF UPSTREAM CONVECTION ACROSS CENTRAL MO AND
E KS SHOULD SUPPORT THIS CONTINUED MERGER ZONE INTO SOUTHEAST MO
AND WESTERN KY BY 11Z. 

CURRENT THINKING IS THIS INTERSECTION SHOULD TRACK ALONG THE
INSTABILITY AXIS AS IT ADVECTS ON THE SOUTH-SOUTHWESTERLY JET INTO
THE SQUALL LINE PER TRENDS IN THE RAP.  THE HRRR PROBABLY HANDLES
THE SITUATION THE BEST OF THE HI-RESOLUTION MODELS AS THE MAXIMA
TRENDS TOWARD THE WEST RUN TO RUN. HOWEVER...EACH RUN CONTINUES TO
PUSH THE AXIS OF HIGHEST TOTALS FURTHER EAST INTO SOUTHERN IN AND
CENTRAL KY WHICH HAS NOT COME TO FRUITION WITH PRIOR RUNS.  SO
MAXIMIZED THREAT FOR FLASH FLOODING REMAINS ALONG THE INSTABILITY
AXIS ACROSS SOUTHERN ILLINOIS...SOUTHEAST MISSOURI.   

GALLINA

ATTN...WFO...ILX...LSX...PAH...

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

LAT...LON   39138910 38648779 38128828 36668866 37509112 
            38439054