077  
FXUS63 KILX 070818  
AFDILX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LINCOLN IL  
318 AM CDT TUE JUL 7 2015  
   
SHORT TERM
 
(TODAY)  
ISSUED AT 318 AM CDT TUE JUL 7 2015  
 
07Z/2AM SURFACE ANALYSIS SHOWS COLD FRONT EXTENDING FROM SOUTHERN  
LAKE MICHIGAN SOUTHWESTWARD TO OKLAHOMA. SEVERAL WEAK WAVES OF LOW  
LOW PRESSURE ARE NOTED ALONG THE BOUNDARY...INCLUDING ONE JUST WEST  
OF KAAA AND ANOTHER UPSTREAM ACROSS CENTRAL MISSOURI. LATEST RADAR  
IMAGERY SHOWS INITIAL LINE OF SHOWERS HAS NOW PUSHED JUST EAST OF  
THE I-55 CORRIDOR...HOWEVER ANOTHER AREA OF SHOWERS WITH A FEW  
EMBEDDED THUNDERSTORMS IS TRACKING NORTHEASTWARD OUT OF MISSOURI AND  
WILL SPREAD ACROSS THE WESTERN HALF OF THE KILX CWA OVER THE NEXT  
FEW HOURS. ONCE THE MISSOURI LOW TRACKS INTO NORTHEAST ILLINOIS BY  
MIDDAY...THE COLD FRONT WILL GET PULLED TOWARD THE I-57 CORRIDOR AND  
PRECIP CHANCES WILL WANE ACROSS THE WEST THIS AFTERNOON. HAVE GONE  
WITH CATEGORICAL POPS FOR SHOWERS ACROSS THE BOARD THIS  
MORNING...THEN HAVE ENDED RAIN CHANCES NORTHWEST OF A BLOOMINGTON TO  
JACKSONVILLE LINE BY EARLY AFTERNOON. DUE TO EXTENSIVE CLOUD COVER  
AND OFF AND ON SHOWERS...TEMPERATURES WILL BE HELD DOWN CONSIDERABLY  
TODAY...WITH AFTERNOON HIGHS MAINLY IN THE MIDDLE TO UPPER 70S.  
 

 
   
LONG TERM
 
(TONIGHT THROUGH MONDAY)  
ISSUED AT 318 AM CDT TUE JUL 7 2015  
 
AS WAS FIRST SUGGESTED BY THE 00Z JULY 6 ECMWF...THE LATEST MODEL  
RUNS ARE NOW PUSHING THE FRONT FAR ENOUGH SOUTH TO ALLOW MUCH OF THE  
CWA TO EXPERIENCE A BREAK IN THE PRECIP CHANCES TONIGHT. WITH  
BOUNDARY STALLING ALONG THE OHIO RIVER...HAVE CONFINED RAIN CHANCES  
TO LOCATIONS ALONG/SOUTH OF A PARIS TO TAYLORVILLE LINE. FURTHER  
NORTH...HIGH PRESSURE BUILDING INTO THE GREAT LAKES WILL PROVIDE  
COOLER/DRIER WEATHER WITH LOW TEMPERATURES DIPPING INTO THE 50S.  
 
WAVE OF LOW PRESSURE IS STILL EXPECTED TO DEVELOP ALONG THE TRAILING  
END OF THE FRONT OVER NORTHERN TEXAS LATE TUESDAY...THEN TRACK  
NORTHEASTWARD ACROSS CENTRAL ILLINOIS WEDNESDAY NIGHT. AS THE LOW  
APPROACHES...SHOWERS AND THUNDERSTORMS WILL OVERSPREAD THE ENTIRE  
AREA ON WEDNESDAY THEN CONTINUE THROUGH WEDNESDAY NIGHT. TOTAL QPF  
FROM THIS EVENT WILL GENERALLY RANGE FROM 1 TO 1.25 ACROSS MUCH OF  
THE AREA...WITH LOWER AMOUNTS ALONG/NORTHWEST OF THE ILLINOIS RIVER.  
 
ONCE THE LOW LIFTS INTO NORTHERN INDIANA...SHORT-WAVE RIDGING IN ITS  
WAKE WILL PROVIDE SYNOPTIC SUBSIDENCE AND ANOTHER BREAK IN PRECIP  
CHANCES ON THURSDAY. HAVE HELD ON TO SLIGHT CHANCE POPS ACROSS THE  
SOUTHERN HALF OF THE AREA IN CLOSER PROXIMITY TO THE PREVAILING  
BAROCLINIC ZONE...BUT THINK THURSDAY WILL BE LARGELY DRY. NEXT  
PRECIP EVENT WILL UNFOLD THURSDAY NIGHT INTO FRIDAY MORNING AS  
NOCTURNAL LOW-LEVEL JET FOCUSES ALONG THE FRONT ACROSS NORTHERN  
MISSOURI INTO SOUTHERN IOWA. MODEL CONSENSUS SHOWS A STORM COMPLEX  
DEVELOPING ACROSS THIS AREA OVERNIGHT...THEN SHIFTING E/NE INTO  
NORTH-CENTRAL ILLINOIS EARLY FRIDAY. HAVE GONE WITH LIKELY POPS  
ACROSS THE ILLINOIS RIVER VALLEY THURSDAY NIGHT...TAPERING DOWN TO  
JUST LOW CHANCE ALONG THE INDIANA BORDER. WILL CONTINUE POPS INTO  
FRIDAY...PARTICULARLY ACROSS THE NORTHERN HALF OF THE CWA AS THIS  
COMPLEX MOVES E/NE.  
 
AFTER THAT...MAIN QUESTION FURTHER OUT IN THE EXTENDED WILL BE HOW  
STRONG THE UPPER-LEVEL RIDGING WILL BECOME THIS WEEKEND. GFS  
CONTINUES TO SHOW A STRONG RIDGE WITH A STORM TRACK WELL TO THE  
NORTH ACROSS THE SOUTHERN GREAT LAKES...WHILE THE ECMWF FEATURES A  
SLIGHTLY WEAKER RIDGE. EVEN THE WEAKER ECMWF SHOWS MUCH OF THE  
NOCTURNAL CONVECTION TOPPING THE RIDGE REMAINING JUST NORTH OF THE  
CWA...SO CONFIDENCE IS GROWING FOR A HOT AND LARGELY DRY WEEKEND.  
AS SUCH...HAVE ONLY INCLUDED SLIGHT CHANCE POPS ACROSS THE FAR NORTH  
FRIDAY NIGHT AND SATURDAY NIGHT AND HAVE RAISED HIGH TEMPS INTO THE  
UPPER 80S TO AROUND 90 DEGREES FOR BOTH SATURDAY AND SUNDAY. RIDGE  
WILL SHIFT WESTWARD INTO THE CENTRAL/SOUTHERN PLAINS EARLY NEXT WEEK  
AND A DOWNSTREAM TROUGH WILL DIG OVER THE GREAT LAKES/MIDWEST. THIS  
WILL MEAN INCREASING RAIN CHANCES AND COOLER WEATHER BY MONDAY INTO  
TUESDAY.  
 

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)  
ISSUED AT 1100 PM CDT MON JUL 6 2015  
 
BAND OF SHOWERS AND ISOLATED THUNDERSTORMS CONTINUES TO MARCH  
SLOWLY EAST AND SOUTHEAST LATE THIS EVENING AND WILL CONTINUE  
TO DO SO INTO THE EARLY MORNING HOURS. A COLD FRONT OUT TO OUR  
WEST WILL PUSH ACROSS THE ILLINOIS RIVER VALLEY BETWEEN 07Z AND  
10Z...THE I-55 CORRIDOR BETWEEN 10Z-14Z AND POINTS FURTHER EAST  
IN THE 14Z-18Z TIME FRAME. IT IS RIGHT ALONG AND BEHIND THE COLD  
FRONT WHERE WE SEE CIGS DROP TO MVFR WITH SOME AREAS OF IFR CIGS  
POSSIBLE TUESDAY MORNING. SOMEWHAT DRIER AIR WILL ADVECT SOUTH  
INTO NORTH CENTRAL IL TUESDAY AFTERNOON AND WE SHOULD SEE CIGS  
IMPROVE TO VFR AFTR 19Z...WITH THE MVFR CIGS HOLDING FURTHER  
SOUTH UNTIL EVENING. SURFACE WINDS WILL GRADUALLY VEER INTO THE  
SOUTHWEST AND WEST AT 8 TO 13 KTS OVERNIGHT AND INTO THE NORTHEAST  
AT 10 TO 15 KTS AFTR FROPA TOMORROW MORNING AND HOLD FROM A  
NORTHEAST DIRECTION INTO THE EVENING.  
 

 
   
ILX WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
SHORT TERM...BARNES  
LONG TERM...BARNES  
AVIATION...SMITH  
 
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