MESOSCALE PRECIPITATION DISCUSSION 0216
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
751 AM EDT MON JUN 15 2015
 
AREAS AFFECTED...NORTHERN ILLINOIS...SOUTHERN WISCONSIN...EASTERN
IOWA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 151150Z - 151650Z
 
SUMMARY...SLIGHT UPTICK IN CONVECTIVE DEVELOPMENT ALLOWING FOR
SCATTERED CELLS CAPABLE OF PRODUCING RATES IN EXCESS OF LOCAL
FLASH FLOOD GUIDANCE.

DISCUSSION...WELL DEFINED UPPER LEVEL VORT LOCATED IN EASTERN OF
NEBRASKA WITH ASSOCIATED  WEAK BANDS OR WAVES OF MID-LEVEL ENERGY
EJECTING EASTWARD OUT OF THE SOUTHWESTERLY FLOW CURRENTLY LOCATE
NEAR MIW IN IOWA AND EAST OF RFD IN NORTHERN ILLINOIS.  THESE WEAK
WAVES IN CONCERT WITH UPPER LEVEL DIVERGENCE SUPPORT ON THE SOUTH
SIDE OF A DEVELOPING JET HAVE ALLOWED FOR INCREASED UVV FOR
SCATTERED CELLS TO DEVELOP JUST EAST OF THESE WAVE FEATURES. 
CELLS HAVE AMPLE MOISTURE WITH SATURATED PROFILES SUPPORTING TOTAL
PWATS AOA 2" AND SOME LIMITED BUT SUFFICIENT INSTABILITIES WITH
SBCAPES IN THE 500-750 J/KG RANGE.  THIS HAS ALLOWED FOR EFFICIENT
RAINFALL PRODUCTION WITHIN THESE CELLS FOR 1.25-1.5"/HR RATES
LEADING TO POCKETS/TOTALS OVER 1".  GIVEN THE NEARLY
UNIDIRECTIONAL ORIENTATION OF THE FLOW ABOVE 850MB...SUPPORT FOR
REPEAT OR TRAINING  COULD INCREASE THE FLASH FLOOD THREAT IN
ISOLATED LOCALIZED AREAS ACROSS THE DISCUSSION AREA.  

THOUGH HI-RES MODELS DO SUPPORT THE OVERALL PATTERN OF NARROW
STRIPES OF 1-2" TOTALS ACROSS EAST IOWA/NORTHERN ILLINOIS...
THINKING THE AREA WILL BE A BIT MORE FOCUSED IN AREAL SCOPE ACROSS
NORTHERN ILLINOIS IN PARTICULAR WHERE FLASH FLOOD GUIDANCE IS
LOWEST...OVER THE NEXT 4-5 HOURS FOR THE POTENTIAL FOR LOCALIZED
POSSIBLE FLASH FLOODING.  

PLEASE SEE 1051Z SPENES FROM SAB FOR ADDITIONAL INFORMATION ABOUT
THE ENVIRONMENT UPSTREAM. 

GALLINA

ATTN...WFO...ARX...DMX...DVN...ILX...LOT...MKX...

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

LAT...LON   42928984 42928783 41708753 41218868 40959031 
            41089242 42269273