683  
FXUS63 KILX 302350  
AFDILX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LINCOLN IL  
650 PM CDT MON MAY 30 2016  
   
SHORT TERM
 
(TONIGHT)  
ISSUED AT 226 PM CDT MON MAY 30 2016  
 
ISOLATED SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ALONG A WEAK  
FRONTAL BOUNDARY NEAR I-72 AT MID AFTERNOON AND TRACKING SLOWLY  
SOUTHEAST. THE STRONGEST THUNDERSTORM WAS ALONG THE MACON AND SHELBY  
COUNTY LINE WHERE RADAR ESTIMATES 0.25-0.50 INCH HAIL. SCATTERED TO  
BROKEN CUMULUS CLOUDS GIVING PARTLY TO MOSTLY CLOUDY SKIES THIS  
AFTERNOON. ANOTHER WARM AFTERNOON IN THE MID TO UPPER 80S OVER CWA  
WITH DEWPOINTS IN THE MID 50S TO LOWER 60S. A WEAK SHORT WAVE  
LIFTING NORTHEAST ACROSS CENTRAL IL THIS AFTERNOON WILL ALSO HELP  
SUPPORT ISOLATED CONVECTION INTO EARLY EVENING. MODELS OVERALL  
DEVELOPING MORE QPF OVER WESTERN IL NEAR MS RIVER VALLEY BY  
OVERNIGHT WHILE EASTERN IL STAYS DRIER. THIS QPF AHEAD OF UPPER  
LEVEL TROF ALONG THE KS/MO AND OK/AR BORDER THAT WEAKENS AS IT  
EJECTS NORTHEAST. WEAK SURFACE HIGH PRESSURE OF 1018 MB OVER THE MID  
MS RIVER VALLEY STAYS NEAR CENTRAL/SOUTHEAST IL OVERNIGHT BRINGING  
LIGHT WINDS TONIGHT. SIMILAR MET/MAV LOWS IN THE LOW TO MID 60S  
LOOKS GOOD AGAIN TONIGHT.  
   
LONG TERM
 
(TUESDAY THROUGH MONDAY)  
ISSUED AT 226 PM CDT MON MAY 30 2016  
 
ANOTHER WARM DAY IS ON TAP TUESDAY ACROSS CENTRAL AND SOUTHEAST  
ILLINOIS, WITH MOST LOCATIONS EXPECTED TO TOP OUT IN THE MID 80S.  
MAINLY DIURNALLY DRIVEN SHOWERS/STORMS ARE EXPECTED DURING THE  
AFTERNOON/EVENING HOURS, BUT A STRAY SHOWER OR STORM CAN'T BE RULED  
OUT IN THE MORNING EITHER. INSTABILITY DURING PEAK HEATING WILL BE  
MODEST (AROUND 1000 J/KG OF CAPE), AND SHEAR WILL BE WEAK, SO DON'T  
EXPECT ANY OF THESE STORMS TO BE SEVERE.  
 
BY LATER TUESDAY NIGHT, AN UPPER-LEVEL WAVE (CURRENTLY CENTERED OVER  
MONTANA AND ALBERTA) WILL TRACK EAST ALONG THE U.S./CANADA BORDER.  
THIS SYSTEM WILL PUSH AN ASSOCIATED COLD FRONT THROUGH THE FORECAST  
AREA ON WEDNESDAY. SHOWER/STORM CHANCES WILL INCREASE ACROSS THE  
FORECAST AREA FROM WEST TO EAST LATE TUESDAY NIGHT, WITH THE HIGHEST  
RAINFALL CHANCES SEEN ON WEDNESDAY. INSTABILITY WILL BE COMPARABLE  
OR A LITTLE STRONGER THAN TUESDAY, AND SHEAR WILL STILL BE RATHER  
WEAK DESPITE THE PASSAGE OF THE SYSTEM. THE SEVERE STORM RISK SHOULD  
REMAIN RATHER LOW AS A RESULT. IF THE FRONT WERE TO BE SLOWER IN  
ARRIVING, THE INSTABILITY COULD BE EVEN GREATER, BUT DO NOT EXPECT  
THIS TO OCCUR GIVEN THE MODEL CONSENSUS AND CURRENT DISTANCE OF THE  
SYSTEM FROM THE AREA.  
 
THURSDAY AND FRIDAY ARE EXPECTED TO BE MOSTLY DRY, AND SOMEWHAT  
COOLER, IN THE WAKE OF THE MIDWEEK SYSTEM/FRONT. THE UPPER-LEVEL  
FLOW WILL BE OUT OF THE NORTHWEST FOR THE DURATION OF THE FORECAST  
PERIOD, AS TROFFING DEVELOPS ACROSS EASTERN NORTH AMERICA, SUPPORTING  
SLIGHTLY COOLER THAN NORMAL TEMPERATURES. A SHORT WAVE WITHIN THIS  
FLOW IS EXPECTED TO PASS THROUGH DURING THE WEEKEND, PROVIDING OUR  
NEXT CHANCE OF SHOWERS/STORMS.  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)  
ISSUED AT 650 PM CDT MON MAY 30 2016  
 
ISOLATED SHOWERS AND THUNDERSTORMS WILL CONTINUE FOR THE FIRST FEW  
HOURS OF THE FORECAST PERIOD BEFORE INSTABILITY DIMINISHES LATER  
IN THE EVENING. HAVE INCLUDED VCTS AT TERMINALS KBMI-KSPI-KCMI  
WHICH APPEAR TO HAVE A LIKELIHOOD OF THUNDERSTORM ACTIVITY IN THE  
VICINITY BASED ON LOCATIONS OF VARIOUS OUTFLOW BOUNDARIES ACROSS  
THE AREA. OTHERWISE...VFR CONDITIONS EXPECTED THROUGH THE NIGHT  
WITH ONLY A SLIGHT CHANCE OF SHOWERS REDEVELOPING LATE IN THE  
NIGHT AS A SHORTWAVE MOVES SLOWLY UP FROM MISSOURI. THE POTENTIAL  
FOR ISOLATED TO SCATTERED INSTABILITY SHOWERS AND THUNDERSTORMS  
WILL RETURN FOR TUESDAY AFTERNOON AND HAVE INCLUDED VCTS IN TAFS  
STARTING 17-18Z. WINDS GENERALLY S-SE LESS THAN 10 KTS THROUGH THE  
PERIOD...ALTHOUGH SOME VARIABLE DIRECTIONS IN THE VICINITY OF  
THUNDERSTORMS AND OUTFLOW BOUNDARIES. SOME LIGHT FOG/HAZE POSSIBLE  
FROM 09Z-13Z WHERE VSBYS COULD LOWER TO 4-6 MILES...ALTHOUGH  
CURRENT GUIDANCE DOESN'T SUGGEST HIGH ENOUGH PROBABILITIES FOR  
INCLUSION IN 00Z TAFS.  
 

 
   
ILX WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  
 

 
 

 
 
SHORT TERM...07  
LONG TERM...BAK  
AVIATION...ONTON  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab IL Page Main Text Page