598  
FXUS63 KILX 041544  
AFDILX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LINCOLN IL  
1044 AM CDT WED MAY 4 2016  
   
UPDATE
 
 
ISSUED AT 1035 AM CDT WED MAY 4 2016  
 
CU DEVELOPMENT TODAY IN MVFR CATEGORY AS 850MB SHOWS STRONG COLD  
AIR ADVECTION OVER THE REGION THROUGH TODAY. SHOULD THEN RIASE  
CIGS TO LOW VFR IN THE AFTERNOON. WILL SEE SCT SHOWER DEVELOPMENT  
IN THE EAST WITH THE UNSTABLE AIRMASS, WITH EVEN A STORM POSSIBLE  
AS STEEP LAPSE RATES. SHOWERS AND CLOUDS SHOULD DISSPIATE  
OVERNIGHT WITH DROP OFF OF AFTERNOON HEATING. GUSY WINDS TODAY IN  
SRONG GRADIENT AND THE COLD AIR ADVECTION BEHIND THE FRONT THAT  
MOVED THROUGH LAST NIGHT. SOME DROP OFF IN WINDS OVERNIGHT.  
 

 
   
SHORT TERM
 
(TODAY)  
ISSUED AT 320 AM CDT WED MAY 4 2016  
 
A BAND OF SHOWERS AND A FEW THUNDERSTORMS IS DIVING ACROSS CENTRAL  
AND SOUTHEAST ILLINOIS EARLY THIS MORNING. THIS CONVECTION LIES JUST  
AHEAD OF A STRONG COLD FRONT, THAT IS DRIVEN BY A VIGOROUS UPPER  
WAVE DIVING INTO THE MIDWEST. THE RAPID MOVEMENT OF THIS  
FRONT/PRECIPITATION WILL HAVE THE RAINFALL COMPLETELY OUT OF THE  
FORECAST AREA BY MID-MORNING. IT WILL BE NOTICEABLE COOLER ACROSS  
THE REGION TODAY BEHIND THE FRONT, WITH MANY AREAS ONLY SEEING HIGH  
TEMPERATURES IN THE 50S. NORTHERLY POST-FRONTAL WINDS GUSTING TO 30  
MPH AT TIMES WILL ALSO MAKE IT FEEL COOLER. PEAK AFTERNOON HEATING  
AND VERY CHILLY AIR ALOFT WILL COMBINE TO PRODUCE STEEP LAPSE RATES  
LATER TODAY. THIS SHOULD ALLOW A FEW SHOWERS OR A THUNDERSTORM TO  
POP THIS AFTERNOON. HOWEVER, COVERAGE SHOULD NOT BE SIGNIFICANT AND  
HAVE LIMITED SLIGHT CHANCE AFTERNOON POPS TO ROUGHLY THE EASTERN  
HALF OF THE FORECAST AREA.  
   
LONG TERM
 
(TONIGHT THROUGH TUESDAY)  
ISSUED AT 320 AM CDT WED MAY 4 2016  
 
UPPER RIDGING CURRENTLY ALONG THE ROCKIES WILL BE EDGING EASTWARD  
THE NEXT COUPLE DAYS, BUT PATTERN OVERALL WILL BE RATHER BLOCKY,  
WITH CLOSED LOWS ON EITHER SIDE OF IT. NO REAL BREAKDOWN EXPECTED  
UNTIL THIS WEEKEND, WHEN AN UPPER WAVE WILL DROP SOUTHEAST FROM  
HUDSON BAY AND FINALLY BOOT THE EASTERN LOW OUT OF THE WAY. HOWEVER,  
THE WESTERN ONE WILL REMAIN IN THE PICTURE UNTIL MONDAY, WITH A  
SURFACE BOUNDARY EXTENDING EASTWARD INTO THE MIDWEST.  
 
LONGER RANGE MODELS ARE IN DECENT AGREEMENT WITH PUSHING THE FRONT  
THROUGH THE AREA BY SATURDAY EVENING, WITH SCATTERED SHOWERS AND  
THUNDERSTORMS DURING THE DAY AND EVENING HOURS, BEFORE DIMINISHING.  
AFTER THAT, THE BOUNDARY BECOMES PARALLEL TO THE UPPER FLOW BETWEEN  
WHAT'S LEFT OF THE RIDGE AND SHORTWAVES ROTATING THROUGH THE GREAT  
LAKES REGION. THE GFS HANGS ONTO THIS UNTIL LATE MONDAY NIGHT BEFORE  
THE FRONT AND ASSOCIATED RAIN CHANCES LIFT BACK NORTH. MEANWHILE,  
THE ECMWF IS MUCH MORE AGGRESSIVE IN PUSHING IT BACK BEGINNING  
SUNDAY EVENING AS THE LINGERING RIDGE AXIS SLIDES OVERHEAD. LEANED  
MORE TOWARD THE LATTER SOLUTION, ALTHOUGH NOT QUITE AS WET, AND HAVE  
CHANCE POP'S OVER MOST OF THE FORECAST AREA SUNDAY NIGHT AND MONDAY.  
WITH THE REMNANTS OF THE WESTERN LOW ONLY INTO THE CENTRAL PLAINS BY  
TUESDAY, RAIN CHANCES WILL BE STEADILY INCREASING WITH TIME EARLY  
NEXT WEEK.  
 
A WARMING TREND WILL COMMENCE ON THURSDAY, WITH HIGHS MOSTLY IN THE  
MID 60S. AS THE THERMAL RIDGE BUILDS EAST LATE IN THE WEEK, A COUPLE  
DAYS ARE EXPECTED WITH TEMPERATURES REACHING NEAR 80 DEGREES, BEFORE  
THE FRONT PUSHES THROUGH. HOWEVER, WITH THE MAIN TROUGHING REMAINING  
NEAR THE GREAT LAKES, TEMPERATURES BEHIND THE FRONT SHOULD NOT BE  
ESPECIALLY COOLER.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)  
ISSUED AT 635 AM CDT WED MAY 4 2016  
 
PREDOMINANTLY VFR CONDITIONS EXPECTED ACROSS THE CENTRAL ILLINOIS  
TERMINALS TODAY, ALTHOUGH A FEW PATCHES OF STRATUS/FOG WILL BE IN  
THE AREA FOR THE NEXT HOUR OR TWO. LOW END VFR CIGS WILL DEVELOP  
AROUND MIDDAY AND POSSIBLY RESULT IN A FEW SHOWERS, ESPECIALLY  
TOWARD THE INDIANA BORDER. GUSTY NORTHERLY WINDS ARE EXPECTED TO  
DEVELOP SHORTLY, AND LINGER UNTIL THIS EVENING.  
 

 
   
ILX WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
UPDATE...GOETSCH  
SHORT TERM...BAK  
LONG TERM...GEELHART  
AVIATION...BAK  
 
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