152  
FXUS63 KILX 011204  
AFDILX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LINCOLN IL  
704 AM CDT WED OCT 1 2014  
   
SHORT TERM
 
(TODAY)  
ISSUED AT 258 AM CDT WED OCT 1 2014  
 
THE UPPER-LEVEL RIDGE OF HIGH PRESSURE THAT HAS BROUGHT MUCH ABOVE  
NORMAL TEMPERATURES TO THE MIDWEST OVER THE PAST SEVERAL DAYS WILL  
SLOWLY LOSE ITS INFLUENCE TODAY AS A LONG-WAVE TROUGH OVER THE  
WESTERN HALF OF THE CONUS BEGINS TO TRANSLATE EASTWARD. 07Z/2AM  
WATER VAPOR IMAGERY SHOWS A SERIES OF SHORT-WAVES EMBEDDED WITHIN  
THE PARENT TROUGH, WITH A LEAD WAVE CURRENTLY EJECTING INTO  
WESTERN KANSAS/NEBRASKA AND ANOTHER WAVE FURTHER UPSTREAM OVER THE  
GREAT BASIN. THE FIRST WAVE WILL LIFT N/NE TODAY, REMAINING WELL  
WEST OF ILLINOIS. AS A RESULT, CONVECTION ASSOCIATED WITH THIS  
FEATURE ACROSS EASTERN KANSAS INTO CENTRAL/WESTERN IOWA WILL TRACK  
MAINLY NORTHWARD INTO MINNESOTA/WISCONSIN AS THE DAY PROGRESSES.  
SOME MODELS ARE SUGGESTING THAT PRECIP MAY REACH THE FAR WESTERN  
KILX CWA BY LATE AFTERNOON: HOWEVER, GIVEN DRY AIRMASS INITIALLY  
IN PLACE AND A CONTINUED EASTERLY COMPONENT TO THE WIND, THINK  
THIS IS A BIT TOO AGGRESSIVE. WILL THEREFORE GO WITH A DRY  
FORECAST ACROSS THE BOARD TODAY. SKIES WILL START OUT MOSTLY  
SUNNY, WITH A GRADUAL INCREASE IN CLOUD COVER DURING THE AFTERNOON  
WEST OF I-55. THANKS TO THE SUNSHINE AND WINDS VEERING TO THE  
SOUTHEAST, HIGH TEMPERATURES WILL REACH THE UPPER 70S AND LOWER  
80S.  
 

 
   
LONG TERM
 
(TONIGHT THROUGH TUESDAY)  
ISSUED AT 258 AM CDT WED OCT 1 2014  
 
INITIAL SHORT-WAVE WILL PASS TO THE W/NW OF ILLINOIS THIS EVENING,  
WHILE GREAT BASIN FEATURE EJECTS INTO THE PLAINS AND INDUCES SURFACE  
CYCLOGENESIS OVER THE TEXAS/OKLAHOMA PANHANDLES. AS THIS LOW BEGINS  
TO LIFT N/NE AND AIRMASS MOISTENS, SHOWERS AND THUNDERSTORMS WILL  
DEVELOP ACROSS WEST-CENTRAL ILLINOIS DURING THE EVENING THEN SPREAD  
EASTWARD TOWARD THE INDIANA BORDER BY THURSDAY MORNING. WITH BEST  
FORCING ASSOCIATED WITH THE SECOND WAVE REMAINING TO THE SOUTHWEST  
AND FORECAST SOUNDINGS STILL SHOWING A DRY LAYER BELOW 850MB, HAVE  
OPTED TO REDUCE POPS TO JUST CHANCE ALONG/WEST OF I-55 THIS  
EVENING. THINK BETTER RAIN CHANCES WILL ARRIVE MAINLY ACROSS THE  
WESTERN CWA AFTER MIDNIGHT, WITH AREAS FURTHER EAST NEAR THE INDIANA  
BORDER LIKELY STAYING DRY THROUGH THE ENTIRE NIGHT.  
 
LOW PRESSURE OVER OKLAHOMA THURSDAY MORNING WILL TRACK NORTHEASTWARD  
INTO WISCONSIN BY THURSDAY NIGHT. AS IT DOES, IT WILL DRAG A STRONG  
COLD FRONT THROUGH CENTRAL ILLINOIS. MODELS HAVE BEEN TRENDING  
SLIGHTLY SLOWER WITH THE FRONT, WITH MOST SOLUTIONS NOW SHOWING  
FROPA OVERNIGHT THURSDAY. WITH STRONGEST FORCING FOR CONVECTION  
STAYING TO THE WEST NEAR THE LOW AND ASSOCIATED FRONT, HAVE FOCUSED  
HIGHEST POPS IN THE LIKELY CATEGORY ACROSS THE WESTERN HALF OF THE  
CWA ON THURSDAY WITH ONLY CHANCE POPS ALONG/EAST OF I-57. WILL BE  
ANOTHER WARM DAY WITH HIGHS RANGING FROM THE MIDDLE 70S FAR  
NORTHWEST AROUND GALESBURG TO THE MIDDLE 80S ALONG/SOUTH OF I-70.  
 
MAIN CONVECTIVE EVENT STILL APPEARS TO BE ON TRACK FOR THURSDAY  
NIGHT AS FRONT INTERACTS WITH AN UNSEASONABLY MOIST AIRMASS  
CHARACTERIZED BY PRECIPITABLE WATER VALUES IN EXCESS OF 1.50. GIVEN  
AMPLE DEEP-LAYER MOISTURE AND STRONG UPPER DYNAMICS, WILL CARRY  
CATEGORICAL POPS ACROSS THE BOARD. LATEST CONVECTIVE OUTLOOK FROM  
SPC SUGGESTS THE POTENTIAL FOR STRONG TO SEVERE STORMS THURSDAY  
EVENING AS A SQUALL LINE DEVELOPS ALONG/AHEAD OF THE FRONT.  
 
FRONT WILL SWEEP INTO INDIANA BY FRIDAY MORNING, WITH A FEW  
LINGERING SHOWERS POSSIBLE ACROSS THE WABASH RIVER VALLEY EARLY IN  
THE DAY. MAIN STORY ON FRIDAY WILL BE THE WINDY AND MUCH COOLER  
CONDITIONS. DUE TO A TIGHTENING PRESSURE GRADIENT AND ADEQUATE  
MIXING, W/NW WINDS MAY GUST TO AROUND 30MPH AT TIMES. HIGH  
TEMPERATURES WILL MAINLY BE IN THE 60S. AN UPPER WAVE DIGGING  
SOUTHWARD OUT OF CANADA MAY TRIGGER SCATTERED SHOWERS ACROSS THE  
REGION FRIDAY AFTERNOON/NIGHT. TIMING DISCREPANCIES STILL EXIST  
AMONG THE MODELS, SO WILL ONLY MENTION SLIGHT CHANCE FOR SHOWERS  
FRIDAY NIGHT AT THIS TIME. ONCE THIS FEATURE PASSES, VERY COOL AND  
DRY CONDITIONS ARE ANTICIPATED THIS WEEKEND. COOLEST DAY WILL BE  
SATURDAY WHEN HIGHS WILL REMAIN IN THE 50S AND OVERNIGHT LOWS WILL  
DIP INTO THE UPPER 30S. AFTER THAT, NORTHWESTERLY FLOW WILL  
PREVAIL THROUGH THE MIDDLE OF NEXT WEEK, RESULTING IN A  
CONTINUATION OF BELOW NORMAL TEMPS. AIRMASS MODIFICATION WILL  
ALLOW TEMPS TO SLOWLY CLIMB BACK INTO THE UPPER 60S BY TUESDAY.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)  
ISSUED AT 700 AM CDT WED OCT 1 2014  
 
EXPECT VFR CONDITIONS ALL DAY TODAY WITH INCREASING HIGH CLOUDS  
THIS AFTERNOON AS SHOWERS AND STORMS ADVANCE GRADUALLY EASTWARD  
ACROSS N MISSOURI AND E IOWA. THAT INITIAL WAVE WILL PRIMARILY  
LIFT TOWARD S WISCONSIN, WITH RESIDUAL LIFT MOVING EAST INTO  
WESTERN ILLINOIS. SHOWERS AND STORMS SHOULD HOLD OFF NEAR THE  
TERMINAL SITES UNTIL 02Z FOR PIA AND SPI, ADVANCING SLOWLY EAST  
TOWARD CMI AFTER 09Z. THE BEST CHANCES FOR STEADY RAINS WILL BE  
FOR PIA AND SPI LATE TONIGHT WHERE SYNOPTIC SCALE LIFT APPEARS TO  
BE STRONGEST IN TIME-SECTION ANALYSIS. MVFR CLOUDS COULD DEVELOP  
ONCE THE SHOWERS AND STORMS REACH ANY TAF SITE, BUT WE KEPT VFR  
CLOUDS FOR NOW.  
 
WINDS WILL REMAIN PRIMARILY SOUTHEAST TODAY IN THE 7 TO 12KT  
RANGE. THE COLD FRONTAL PASSAGE IS NOT EXPECTED UNTIL THURSDAY  
EVENING, SO SOUTH TO SOUTHEAST WINDS WILL CONTINUE FOR MUCH OF THE  
NEXT TWO DAYS.  
 

 
   
ILX WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
SHORT TERM...BARNES  
LONG TERM...BARNES  
AVIATION...SHIMON  
 
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