484  
FXUS63 KILX 281202  
AFDILX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LINCOLN IL  
702 AM CDT TUE MAR 28 2017  
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 319 AM CDT TUE MAR 28 2017  
 
AS THE LOW PRESSURE AREA THAT BROUGHT RAIN TO THE CWA YESTERDAY  
MOVES OFF TO THE EAST, A BRIEF PERIOD OF DRY WEATHER IS EXPECTED AS  
A HIGH PRESSURE RIDGE SLIDES ACROSS THE AREA TODAY THROUGH TONIGHT.  
WINDS WILL REMAIN NORTH TO NORTHEASTERLY THROUGH TONIGHT, WHICH  
SHOULD KEEP CLOUD COVER OVER THE AREA THE WHOLE TIME. THIS CLOUD  
COVER AND NORTHERLY-NORTHEASTERLY WINDS WILL KEEP TEMPS DOWN AS  
WELL. EXPECTING HIGHS MAINLY IN THE 50S, WITH LOWER 60S IN THE  
SOUTHEAST. OVERNIGHT LOWS WILL BE IN THE 40S.  
   
LONG TERM
 
(WEDNESDAY THROUGH MONDAY)  
ISSUED AT 319 AM CDT TUE MAR 28 2017  
 
AN ACTIVE WEATHER PATTERN IS EXPECTED TO PERSIST ACROSS CENTRAL AND  
SOUTHEAST ILLINOIS OVER THE NEXT SEVERAL DAYS. WHILE NOT EVERY DAY  
WILL SEE RAIN IN THE AREA, THERE WILL BE A FREQUENT RISK. EXPECT  
MOSTLY CLOUDY CONDITIONS TO PERSIST AS WELL, ALONG WITH THE  
PRECIPITATION RISK. TEMPERATURES THROUGH THE PERIOD WILL AVERAGE A  
LITTLE WARMER THAN NORMAL, WITH THE WARMEST READINGS EXPECTED AHEAD  
OF EACH SYSTEM TO IMPACT THE AREA.  
 
QUIET CONDITIONS WILL PERSIST INTO EARLY WEDNESDAY AS UPPER/SURFACE  
RIDGING SLOWLY DRIFT EAST OF THE AREA. THEN, INCREASING  
WAA/ISENTROPIC ASCENT AHEAD OF A SLOW MOVING UPPER LOW/TROF  
(CURRENTLY PUSHING INTO THE FOUR CORNERS REGION) WILL RETURN THE  
THREAT OF SHOWERS TO THE AREA. HOWEVER, MOST OF THE HEAVIER/MORE  
WIDESPREAD RAINFALL SHOULD HOLD OFF UNTIL LATE WEDNESDAY NIGHT INTO  
THURSDAY EVENING AS THE SYSTEM MOVES THROUGH THE AREA. INSTABILITY  
INCREASES AS THE SYSTEM DRAWS CLOSER, PEAKING AROUND 1000 J/KG OVER  
THE SOUTHEAST 1/2 OF THE FORECAST AREA THURSDAY AFTERNOON, AND  
SUPPORTS AT LEAST SCATTERED THUNDERSTORM DEVELOPMENT. RAINFALL  
CHANCES SHOULD BE TAPERING OFF ON FRIDAY AS THE SYSTEM MOVES EAST OF  
THE AREA. WHILE MODEL GUIDANCE IS PRETTY GOOD THAT THE MAIN UPPER  
WAVE WILL PASS THROUGH THE AREA THURSDAY INTO EARLY FRIDAY, THERE IS  
STILL SPREAD WITH THE EXACT TRACK OF THE SYSTEM, INDIVIDUAL SHORT  
WAVES MOVING THROUGH THE MEAN TROF, AND HOW QUICKLY THE SYSTEM  
DEPARTS. EXPECT CURRENT FORECAST TO NEED ADDITIONAL ADJUSTMENTS AS  
MODEL CONSENSUS HOPEFULLY BUILDS AROUND THE DETAILS.  
 
QUIET WEATHER RETURNS FOR FRIDAY NIGHT INTO SATURDAY NIGHT, BUT IT  
WILL NOT LAST FOR LONG AS ANOTHER SYSTEM SHOULD BE IN OUR VICINITY  
FOR SUNDAY INTO TUESDAY. HOWEVER, MODEL AGREEMENT DURING THIS PERIOD  
IS QUITE POOR WITH THE SPECIFICS, RESULTING IN LOW FORECAST  
CONFIDENCE.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)  
ISSUED AT 702 AM CDT TUE MAR 28 2017  
 
CIG HEIGHTS RANGE FROM MVFR TO IFR AT PIA. BASED ON SATELLITE  
LOOPS AND CLOUD TRENDS SEEN ON THE SURFACE MAPS AND OBSERVATIONAL  
DATA, CIG HEIGHTS WILL BE IMPROVING FROM THE NORTHEAST THIS  
MORNING. ALSO BASED ON SATELLITE TRENDS, THIS COULD BE SHORT LIVED  
SINCE OBSERVATIONS SHOW MORE IFR AND MVFR CLOUDS TO THE NORTH AND  
NORTHEAST. SO, WE WILL BRING THE VFR CIGS TO THE SITES THIS  
AFTERNOON, THEN SCATTER THE CLOUDS OUT THIS EVENING. HIRES MODELS  
TRENDING THE WAY OF SCATTERING THINGS OUT THIS EVENING, AND THIS  
LOOKS REASONABLE FOR NOW. HOWEVER, IFR CIGS RETURN LATE TONIGHT IN  
ADVANCE OF THE NEXT WEATHER SYSTEM. WINDS WILL BE NORTHEAST  
THROUGH THE PERIOD.  
 

 
   
ILX WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
SHORT TERM...AUTEN  
LONG TERM...BAK  
AVIATION...AUTEN  
 
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