543  
FXUS63 KILX 030834  
AFDILX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LINCOLN IL  
334 AM CDT WED JUN 3 2020  
   
SYNOPSIS
 
 
ISSUED AT 334 AM CDT WED JUN 3 2020  
 
ANOTHER VERY WARM AND HUMID DAY WILL BE ON TAP ACROSS CENTRAL  
ILLINOIS TODAY AS AFTERNOON HIGH TEMPERATURES TOP OUT IN THE UPPER  
80S TO AROUND 90 DEGREES. SCATTERED THUNDERSTORMS WILL DEVELOP  
ALONG AN ADVANCING COLD FRONT, WITH SOME OF THE STORMS POTENTIALLY  
BECOMING SEVERE THIS AFTERNOON AND EVENING.  
 

 
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 334 AM CDT WED JUN 3 2020  
 
SEVERAL CLUSTERS OF CONVECTION CONTINUE TO TRACK ALONG A NEARLY  
STATIONARY FRONTAL BOUNDARY DRAPED ALONG THE ILLINOIS/WISCONSIN  
BORDER EARLY THIS MORNING. 08Z/3AM RADAR MOSAIC SHOWS ONE STORM  
COMPLEX WELL TO THE EAST OVER SOUTHERN LAKE HURON...WHILE  
ADDITIONAL CLUSTERS FORM UPSTREAM ACROSS NORTHEAST IOWA INTO FAR  
NORTHWEST ILLINOIS. THESE CELLS ARE TRACKING E/SE AND THE REMNANTS  
OF THIS ACTIVITY COULD POTENTIALLY REACH THE N/NW KILX CWA IN THE  
NEXT 3-4 HOURS. HAVE THEREFORE INCLUDED LOW CHANCE POPS FROM THE  
PEORIA AREA NORTHWARD SHORTLY AFTER SUNRISE. THE EARLY MORNING  
CONVECTION WILL TEND TO DISSIPATE, WITH ADDITIONAL STORMS RE-  
DEVELOPING ALONG THE SLOWLY ADVANCING COLD FRONT BY EARLY  
AFTERNOON. LATEST CAMS HAVE SHIFTED CONVECTIVE DEVELOPMENT  
SLIGHTLY FURTHER NORTH FROM PREVIOUS RUNS...AND THIS SEEMS  
REASONABLE GIVEN THAT THE OUTFLOW/EFFECTIVE BOUNDARY CURRENTLY  
REMAINS WELL TO THE NORTH.  
 
AIRMASS AHEAD OF THE FRONT WILL BECOME MODERATELY UNSTABLE, WITH  
HREF ENSEMBLE MEAN SBCAPES REACHING 3000-3500J/KG ALONG THE I-72  
CORRIDOR BY PEAK HEATING. AS HAS BEEN NOTED WITH PREVIOUS MODEL  
CYCLES, WINDS ALOFT WILL BE WEAK AND THE CORRESPONDING 0-6KM BULK  
SHEAR VALUES WILL GENERALLY RANGE FROM 25-30KT. GIVEN GOOD  
INSTABILITY, BUT WEAK SHEAR...THINK SCATTERED STRONG TO SEVERE  
STORM CELLS WILL DEVELOP ALONG THE FRONT THIS AFTERNOON. FORECAST  
SOUNDINGS CONTINUE TO SHOW A DRY SUB-CLOUD LAYER, INDICATIVE OF  
POTENTIAL DAMAGING WIND GUSTS. IN ADDITION, SLOW STORM MOVEMENT  
COULD LEAD TO LOCALIZED HEAVY RAINFALL AND FLASH FLOODING. BASED  
ON MODEL CONSENSUS WITH A STRONG EMPHASIS ON THE THE HRW NSSL,  
HAVE FOCUSED LIKELY POPS ALONG/EAST OF I-55 THIS AFTERNOON THROUGH  
EARLY EVENING...WITH MOST OF THE CONVECTION DROPPING SOUTH OF  
I-70 BEFORE MIDNIGHT. ONCE THE STORMS END, PARTIAL CLEARING WILL  
OCCUR ACROSS THE NORTHERN HALF OF THE CWA OVERNIGHT. GIVEN VERY  
LIGHT WINDS AND A MOIST BOUNDARY LAYER CHARACTERIZED BY DEWPOINTS  
IN THE MIDDLE 60S, WOULD NOT BE SURPRISED TO SEE FOG DEVELOPMENT.  
HAVE THEREFORE INCLUDED PATCHY FOG EVERYWHERE NORTH OF I-70 LATE  
TONIGHT INTO EARLY THURSDAY MORNING.  
 

 
   
LONG TERM
 
(THURSDAY THROUGH TUESDAY)  
ISSUED AT 334 AM CDT WED JUN 3 2020  
 
SCATTERED THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE BOTH THURSDAY  
AND FRIDAY, ALTHOUGH AREAL COVERAGE AND INTENSITY WILL BE LIMITED  
BY THE DISSIPATING FRONTAL BOUNDARY AND AN OVERALL LACK OF UPPER  
SUPPORT. 00Z JUNE 3 MODELS ARE ALL IN EXCELLENT AGREEMENT THAT THE  
UPPER RIDGE WILL RE-BUILD OVER THE REGION THIS WEEKEND, RESULTING  
IN WARM/DRY WEATHER FROM SATURDAY THROUGH MONDAY. AFTER THAT,  
ATTENTION WILL TURN TO THE TROPICS AS THE REMNANTS OF TROPICAL  
STORM CRISTOBAL CURRENTLY IN THE SOUTHWEST GULF OF MEXICO NEAR THE  
YUCATAN PENINSULA TRACKS NORTHWARD THROUGH THE LOWER MISSISSIPPI  
RIVER VALLEY. A SHORT-WAVE TROUGH PUSHING ACROSS THE PLAINS IS  
EXPECTED TO INTERCEPT THIS SYSTEM AND POTENTIALLY BRING HEAVY  
RAINFALL TO PORTIONS OF THE MIDWEST. DETAILS REMAIN UNCERTAIN AT  
THIS POINT, ALTHOUGH THE GFS/ECMWF CONSENSUS SUGGESTS THE MOST  
FAVORED TIME PERIOD FOR RAINFALL ACROSS CENTRAL ILLINOIS WILL  
LIKELY BE LATE TUESDAY INTO WEDNESDAY.  
 

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)  
ISSUED AT 1125 PM CDT TUE JUN 2 2020  
 
MODEST SOUTHWEST BREEZE AND VFR CONDITIONS ARE LIKELY OVERNIGHT.  
WILL HAVE TO MONITOR AN OUTFLOW BOUNDARY SAGGING SOUTH ACROSS  
NORTHERN ILLINOIS FOR A POSSIBLE WIND SHIFT OR ISOLATED  
THUNDERSTORM OVERNIGHT, HOWEVER, THINK THIS BOUNDARY SHOULD SLOW  
AND STALL NORTH OF THE TERMINALS OVERNIGHT. SHOWERS AND  
THUNDERSTORMS WILL REDEVELOP ON THE BOUNDARY WEDNESDAY AFTERNOON  
AND MAKE ANOTHER PUSH SOUTH ACROSS CENTRAL ILLINOIS. WINDS WILL  
VEER TO THE WEST AHEAD OF THE BOUNDARY, THEN SOME TYPE OF  
NORTHERLY BEHIND THE BOUNDARY, THOUGH CONFIDENCE IS LOW BECAUSE  
WIND FLOW WILL LIKELY BE DISTURBED BY STORMS IN THE AREA. STORMS  
WILL EVENTUALLY SETTLE SOUTH OF THE TERMINALS DURING THE EVENING.  
 

 
   
ILX WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
SYNOPSIS...BARNES  
SHORT TERM...BARNES  
LONG TERM...BARNES  
AVIATION...DEUBELBEISS  
 
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