438  
FXUS63 KILX 281957  
AFDILX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LINCOLN IL  
257 PM CDT SAT MAR 28 2015  
   
SHORT TERM
 
(TONIGHT)  
ISSUED AT 251 PM CDT SAT MAR 28 2015  
 
HIGH PRESSURE CENTERED OVER SOUTHERN LAKE MICHIGAN EARLY THIS  
AFTERNOON IS RESULTING IN LITTLE AFTERNOON CLOUD COVER OVER OUR  
AREA. EARLIER MID/HIGH CLOUDS ASSOCIATED WITH THE MISSOURI SHORTWAVE  
MOVED OUT LATE THIS MORNING. STILL RATHER CHILLY FOR THIS TIME OF  
YEAR, WITH TEMPERATURES MOSTLY IN THE MID-UPPER 30S AS OF 2 PM.  
 
FOCUS THROUGH THE NIGHT WILL BE WITH THE SHORTWAVE CURRENTLY PUSHING  
THROUGH MONTANA, WHICH IS PROGGED TO BE APPROACHING WESTERN  
WISCONSIN/NORTHWEST ILLINOIS EARLY SUNDAY MORNING. ONLY SIGNIFICANT  
IMPACT FOR US BEFORE SUNRISE WILL BE WITH INCREASING SOUTHERLY WINDS  
AFTER MIDNIGHT, AS THE PRESSURE GRADIENT BEGINS TO TIGHTEN. HIGH  
CLOUDS WILL BE ON THE INCREASE AS WELL ACROSS THE NORTHWEST CWA,  
WHILE THE SOUTHEAST REMAINS MOSTLY CLEAR THROUGH THE NIGHT. THE  
INCREASE IN WINDS WILL SLOW THE TEMPERATURE DESCENT OVERNIGHT, WITH  
MOST AREAS SEEING FAIRLY STEADY TEMPERATURES AFTER MIDNIGHT.  
 

 
   
LONG TERM
 
(SUNDAY THROUGH SATURDAY)  
ISSUED AT 251 PM CDT SAT MAR 28 2015  
 
FAST MOVING SHORTWAVE AND FRONTAL BOUNDARY WILL AFFECT THE AREA ON  
SUNDAY BRINGING GUSTY SOUTH WINDS AND LIGHT RAIN TO MOST OF THE  
FORECAST AREA. FAIRLY DECENT LIFT AND IMPRESSIVE 700-500 MB LAPSE RATES  
SUGGEST AN ISOLATED RUMBLE OR TWO OF THUNDER NOT OUT OF THE QUESTION  
IN THE MORNING. STILL THINKING BY THE TIME THE PRECIP GETS INTO OUR  
FAR NORTHWEST COUNTIES SUNDAY MORNING, SURFACE TEMPERATURES SHOULD  
HAVE RISEN ABOVE FREEZING SO WILL CONTINUE FROM PREVIOUS FORECAST  
IN NOT INCLUDING ANY MENTION OF FREEZING PRECIP AS THE RAIN SPREADS  
EAST AS THE MORNING WEARS ON. LOWEST POPS CONTINUE TO BE OVER  
SOUTHEAST ILLINOIS IN THE MORNING WITH HIGH CHANCE POPS IN THE  
AFTERNOON AND EARLY EVENING BEFORE THE RAIN THREAT SHIFTS OFF TO  
OUR EAST BY SUNSET. FORECAST SOUNDINGS CONTINUE TO SUGGEST SOME  
GUSTY WINDS STARTING UP BY MID-MORNING INTO THE LATE AFTERNOON  
HOURS WITH GUSTS AROUND 35 MPH AT TIMES, ESPECIALLY ACROSS THE  
NORTHERN THIRD OF THE FORECAST AREA. WOULDN'T BE SURPRISED TO SEE  
A FEW GUSTS APPROACH 40 MPH AT BLOOMINGTON AND CHAMPAIGN EARLY IN  
THE AFTERNOON.  
 
THE UPPER FORCING IS FORECAST TO SHIFT AWAY FROM THE AREA SUNDAY  
EVENING WITH HIGH PRESSURE SETTLING IN FROM THE WEST ON MONDAY INTO  
EARLY TUESDAY BEFORE ANOTHER SHORTWAVE APPROACHES THE AREA MONDAY  
NIGHT INTO TUESDAY. MODELS CONTINUE TO INDICATE THE BETTER LIFT AND  
MOISTURE WITH THIS SYSTEM WILL REMAIN TO OUR NORTH SO WILL CONTINUE  
TO KEEP RAIN CHANCES OUT OF OUR AREA INTO TUESDAY. AS THE SHORTWAVE  
SHIFTS AWAY FROM THE MIDWEST ON TUESDAY, THE FRONT WILL SETTLE  
SOUTHEAST INTO THE OHIO RIVER VALLEY BY TUESDAY EVENING AS SURFACE HIGH  
PRESSURE EDGES SOUTHEAST ACROSS THE GREAT LAKES. MODELS DO INDICATE A  
WEAK UPPER WAVE OVER SOUTHEAST KS INTO NORTHWEST ARKANSAS LATE  
TUESDAY WITH SOME SHOWERS ASSOCIATED WITH THAT FEATURE, EXPECTED TO  
STAY SOUTH OF OUR FORECAST AREA TUESDAY NIGHT INTO WEDNESDAY. THE  
LASTEST ECMWF DOES INDICATE A JOG TO THE NORTHEAST FROM THE WEAK  
SHORTWAVE INTO THE OHIO VALLEY LATE WEDNESDAY, WHICH MAY BE IN  
RESPONSE TO THE STRONGER NORTHERN STREAM SHORTWAVE OVER THE DAKOTAS  
WHICH MAY BE DRAWING THE FEATURE NORTHWARD. AT THIS TIME WILL  
CONTINUE TO KEEP MOST OF OUR AREA DRY THROUGH WEDNESDAY AS MODELS  
SUGGEST A SLOWER TRANSITION OF THE STRONGER NORTHERN STREAM WAVE TO  
THE EAST MID-WEEK AND THE ASSOCIATED PRECIP CHANCES WITH IT.  
 
AFTER WEDNESDAY, WE SEE SOME SIGNIFICANT DIFFERENCES WITH RESPECT TO  
THE UPPER TROF TO OUR WEST AND HOW QUICKLY THE STORM SYSTEM  
ASSOCIATED WITH IT GETS KICKED OUT AND INTO THE MIDWEST TOWARDS THE  
END OF THE WORK WEEK. MODEL CONCENSUS INDICATES AFTER OUR SHOWER AND  
THUNDERSTORM CHANCES ON THURSDAY ASSOCIATED WITH A COLD FRONT THAT  
TEMPORARILY SHIFTS SOUTHEAST THURSDAY EVENING, A MUCH STRONGER WAVE  
MOVES UP THE BOUNDARY INTO OUR AREA ON FRIDAY BRINGING ANOTHER ROUND  
OF SHOWERS AND STORMS TO THE REGION. THE 00Z ECMWF INDICATED A MUCH  
STRONGER UPPER WAVE WHICH ACTUALLY BROUGHT THE SURFACE LOW UP  
SHARPLY TO THE WEST OF OUR AREA SUGGESTING THE POTENTIAL FOR HEAVY  
RAIN AND WIDESPREAD SEVERE WEATHER ON FRIDAY, WHILE THE GFS WAS  
FLATTER WITH THE SURFACE LOW TRACK WITH MORE RAIN AND ISOLATED  
STORMS ON FRIDAY AS THE LOW TRACKED MAINLY TO OUR SOUTH. THE LATEST  
ECMWF HAS TRENDED TOWARDS THE LAST TWO RUNS OF THE GFS, BUT STILL  
BRINGS THE LOW A BIT FURTHER NORTH ON FRIDAY, RESULTING IN THE  
POTENTIAL FOR HEAVY RAINFALL, ESPECIALLY ACROSS OUR NORTH. LOOKS  
LIKE A RATHER ACTIVE PATTERN TO END THE MONTH OF MARCH WITH OVER  
THE MIDWEST.  
 

 
   
AVIATION
 
(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)  
ISSUED AT 1235 PM CDT SAT MAR 28 2015  
 
MAIN TAF CONCERNS WILL BE IN THE PERIOD AFTER 06Z. BEFORE THEN,  
WINDS GENERALLY TRENDING EAST-SOUTHEAST WITH MOSTLY CLEAR SKIES  
PREVAILING. AFTER THAT, FOCUS SHIFTS TO AN INCOMING FRONTAL  
BOUNDARY FROM THE NORTHWEST. SOUTHEAST WINDS EXPECTED TO INCREASE  
TO ABOVE 10 KNOTS OVERNIGHT AS THE PRESSURE GRADIENT TIGHTENS. ON  
SUNDAY MORNING, WINDS TURN SOUTHERLY AND WILL BE GUSTING 20-30  
KNOTS MUCH OF THE MORNING, AS A LOW LEVEL JET MOVES OVERHEAD.  
PERIOD OF RAIN SHOWERS EXPECTED TO SPREAD EASTWARD DURING THE  
15-18Z TIME FRAME. SOME OF THE MODEL GUIDANCE SUGGESTS SOME  
THUNDER POTENTIAL LATE SUNDAY MORNING, BUT ENOUGH UNCERTAINTY  
EXISTS TO LEAVE IT OUT OF THE FORECAST FOR NOW. CEILINGS WILL  
GRADUALLY LOWER AND SHOULD BE IN THE LOW-END VFR RANGE AS THE  
SHOWERS MOVE THROUGH.  
 

 
   
ILX WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
SHORT TERM...GEELHART  
LONG TERM...SMITH  
AVIATION...GEELHART  
 
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