133  
FXUS63 KILX 261531  
AFDILX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LINCOLN IL  
931 AM CST WED NOV 26 2014  
   
UPDATE
 
 
ISSUED AT 930 AM CST WED NOV 26 2014  
 
VIGOROUS CLIPPER SYSTEM CONTINUES TO DROP SOUTHEAST, WITH THE LOW  
CENTER CURRENTLY OVER SOUTH CENTRAL IOWA. RADAR ECHOES CONTINUE TO  
FILL IN ACROSS WESTERN ILLINOIS, ALTHOUGH THESE SO FAR ARE MAINLY  
MID LEVEL CLOUDS AS THERE WAS A FAIR AMOUNT OF DRY AIR EXHIBITED  
ON OUR MORNING BALLOON SOUNDING. THE COLUMN SHOULD START  
MOISTENING FROM THE TOP DOWN FAIRLY QUICKLY IN WEST CENTRAL  
ILLINOIS, AND LIGHT SNOW SHOULD BE ONGOING OVER THE SOUTHWEST CWA  
BY MIDDAY. SOME OF THIS AREA IS ALREADY UP TO NEAR FREEZING AND  
THERE MAY BE A MIX OF RAIN AND SNOW FOR A COUPLE HOURS, BUT THIS  
SHOULD TREND TOWARD ALL SNOW AS EVAPORATIVE COOLING TAKES PLACE.  
FURTHER EAST, IT LOOKS LIKE THE MAIN TIME FRAME FOR ANY SNOW OR  
MIXED PRECIP WILL BE IN THE AFTERNOON, SO HAVE ADJUSTED THE  
PRECIPITATION TRENDS IN THE GRIDS. HAVE ALSO ADJUSTED POP'S IN THE  
EVENING TO LINGER THEM LONGER ACROSS THE SOUTHWEST HALF OF THE  
FORECAST AREA, BUT THE NORTHEAST SHOULD DRY OUT AS NORTHEAST WINDS  
BRING DRIER AIR BACK IN.  
 

 
   
SHORT TERM
 
(TODAY)  
ISSUED AT 320 AM CST WED NOV 26 2014  
 
08Z/2AM SURFACE CHART SHOWS 1010MB LOW CENTERED JUST NORTH OF OMAHA,  
WITH LIGHT SNOW OBSERVED AS FAR EAST AS THE DES MOINES AREA. 00Z  
NOV 26 MODELS ARE CONSISTENT WITH PRIOR RUNS, SHOWING THE LOW  
TRACKING SOUTHEASTWARD INTO NORTHEAST MISSOURI THIS AFTERNOON, THEN  
INTO THE LOWER OHIO RIVER VALLEY BY EVENING. MODEL QPF FIELDS HAVE  
COME INTO BETTER AGREEMENT, NOW SHOWING A MUCH MORE COMPACT AREA OF  
PRECIP ASSOCIATED WITH THE WAVE SKIRTING ACROSS MAINLY THE W/SW KILX  
CWA TODAY. WITH SO MUCH DRY AIR INITIALLY IN PLACE, THINK THIS  
MAKES SENSE AS PRECIP SHOULD BE CONFINED TO LOCATIONS IMMEDIATELY  
ALONG AND TO THE NORTH OF THE LOW TRACK WHERE LIFT IS STRONGEST. AS  
A RESULT, HAVE CONTINUED TO HIT POPS HARDEST ALONG AND SOUTHWEST OF  
A MACOMB...TO TAYLORVILLE...TO ROBINSON LINE. FORECAST SOUNDINGS  
SUPPORT SNOW AS THE PRECIP BEGINS BY MID TO LATE MORNING: HOWEVER,  
AS SURFACE TEMPERATURES RISE INTO THE MIDDLE TO UPPER 30S THIS  
AFTERNOON, THE SNOW WILL MIX WITH RAIN. THIS WILL SERVE TO MITIGATE  
POTENTIAL ACCUMULATIONS, WHICH ARE STILL EXPECTED TO BE MINIMAL.  
SNOWFALL AMOUNTS OF ONE HALF TO ONE INCH CAN BE EXPECTED  
ALONG/SOUTHWEST OF A GALESBURG TO TAYLORVILLE LINE. FURTHER  
NORTHEAST, HAVE OPTED TO GO WITH A DRY FORECAST ALONG/NORTHEAST OF A  
BLOOMINGTON TO PARIS LINE.  
 

 
   
LONG TERM
 
(TONIGHT THROUGH TUESDAY)  
ISSUED AT 320 AM CST WED NOV 26 2014  
 
LIGHT SNOW WILL LINGER ACROSS MUCH OF CENTRAL AND SOUTHEAST ILLINOIS  
THIS EVENING, AS A TROUGH AXIS EXTENDS NORTHWESTWARD FROM DEPARTING  
LOW PRESSURE IN THE OHIO RIVER VALLEY. A COUPLE TENTHS OF AN INCH  
WILL BE POSSIBLE SOUTH OF I-70 IN CLOSER PROXIMITY TO THE ACTUAL  
LOW, WITH ONLY TRACE AMOUNTS FURTHER NORTHWEST. ANY LIGHT  
SNOW/FLURRIES WILL COME TO AN END OVERNIGHT WITH CLOUDY SKIES  
PERSISTING THROUGH THE NIGHT. STILL SOME QUESTION AS TO HOW QUICKLY  
SKIES WILL CLEAR ON THURSDAY, WITH THE NAM SUGGESTING CLOUDS HANGING  
AROUND FOR MUCH OF THE DAY. GIVEN WHAT HAPPENED WITH THE CLEARING  
TREND YESTERDAY AND THE PRESENCE OF PLENTY OF LINGERING LOW-LEVEL  
MOISTURE ON FORECAST SOUNDINGS, HAVE OPTED TO START THE DAY CLOUDY,  
FOLLOWED BY A GRADUAL WEST-TO-EAST CLEARING BY AFTERNOON. WILL BE A  
MUCH COLDER DAY AS WELL, AS THE DEPARTING CLIPPER SYSTEM TAPS  
INTO A VERY CHILLY AIRMASS OVER SOUTHERN CANADA. A GLANCING BLOW  
OF THIS COLD AIR WILL RESULT IN HIGHS RANGING FROM THE MIDDLE 20S  
NORTH TO THE MIDDLE 30S FAR SOUTH.  
 
THE COLD AIR WILL BE SHORT-LIVED HOWEVER, AS HIGH PRESSURE WILL  
QUICKLY SHIFT EAST OF THE REGION AND A STRONG SOUTHERLY FLOW WILL  
DEVELOP ON FRIDAY. TIGHT PRESSURE GRADIENT WILL LEAD TO WINDS  
GUSTING TO BETWEEN 25 AND 30 MPH AT TIMES, WHICH WILL HELP BOOST  
AFTERNOON HIGHS INTO THE 40S. EVEN WARMER WEATHER IS EXPECTED OVER  
THE WEEKEND, AS DIGGING UPPER TROUGH OVER THE NORTHERN ROCKIES  
INDUCES DOWNSTREAM RIDGING ACROSS THE CENTRAL CONUS. WITH CONTINUED  
SOUTHERLY FLOW AND PARTIAL SUNSHINE, TEMPS WILL SOAR INTO THE LOWER  
TO MIDDLE 50S ON SATURDAY AND MAY EVEN REACH THE LOWER 60S ACROSS  
THE FAR SE CWA ON SUNDAY. AS THE NORTHERN ROCKIES WAVE TRACKS  
EASTWARD ALONG THE NORTHERN TIER OF STATES, IT WILL GRADUALLY PUSH A  
COLD FRONT INTO THE REGION EARLY NEXT WEEK. THERE ARE STILL SOME  
MODEL DISCREPANCIES CONCERNING TIMING OF FROPA AND ANY POTENTIAL  
POPS, WITH THE LATEST MODEL SOLUTIONS DELAYING THE FRONT UNTIL LATE  
SUNDAY. SPRAWLING HIGH PRESSURE ALONG THE GULF COAST WILL LIMIT  
NORTHWARD MOISTURE RETURN, SO THINK PRECIP CHANCES ALONG/AHEAD OF  
THE FRONT WILL BE MINIMAL. WILL CARRY LOW CHANCE POPS ACROSS THE  
CENTRAL/SOUTHERN ZONES SUNDAY, THEN ACROSS THE FAR SOUTH SUNDAY  
NIGHT. FRONT SETTLES SOUTHWARD INTO THE OHIO RIVER VALLEY AND  
ANOTHER SHOT OF COLDER AIR TEMPORARILY ARRIVES ON MONDAY WITH HIGHS  
FALLING BACK INTO THE 30S AND LOWER 40S. AFTER THAT, MODEL  
SOLUTIONS DIVERGE AS GFS BUILDS ANOTHER UPPER RIDGE ACROSS THE  
CENTRAL/EASTERN CONUS ON TUESDAY/WEDNESDAY WHILE THE ECMWF SHOWS A  
MORE PROGRESSIVE ZONAL FLOW CONTINUING. THE LATEST ECMWF IS MUCH  
DIFFERENT THAN ITS PREVIOUS RUN, SO AM SKEPTICAL TO JUMP ON THIS  
SOLUTION JUST YET. AS A RESULT, WILL FOLLOW THE GFS MORE CLOSELY,  
RESULTING IN WARMER WEATHER FOR THE MIDDLE OF NEXT WEEK WITH  
INCREASING RAIN CHANCES COMING INTO THE PICTURE BY WEDNESDAY.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)  
ISSUED AT 548 AM CST WED NOV 26 2014  
 
A CLIPPER SYSTEM WILL IMPACT THE CENTRAL ILLINOIS TERMINALS  
THROUGH THE 12Z TAF VALID TIME. CLOUDS WILL THICKEN AND LOWER THIS  
MORNING INTO THIS AFTERNOON, WITH LIGHT SNOW EXPECTED TO DEVELOP  
DURING THE AFTERNOON. THE SNOW CHANCES, ONCE THEY DEVELOP, WILL  
LINGER INTO THIS EVENING. VFR CONDITIONS SHOULD PREVAIL UNTIL THE  
SNOW BREAKS OUT, WITH KSPI & KDEC MOST LIKELY TO SEE AN EXTENDED  
PERIOD OF MVFR CIGS AND VSBYS. KPIA, KBMI, AND KCMI STAND A BETTER  
CHANCE OF STAYING VFR ONCE THE SNOW DEVELOPS, BUT THEY SHOULD SEE  
AT LEAST A PERIOD OF MVFR VSBYS. SOUTHEAST WINDS WILL START THE  
PERIOD, WITH WINDS TRENDING VARIABLE LATER TODAY AS THE LOW  
PRESSURE CENTER TRACKS NEARBY. NORTHWEST WINDS ARE EXPECTED ON THE  
BACK SIDE OF THE SYSTEM LATER TONIGHT.  
 

 
   
ILX WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
UPDATE...GEELHART/EJL  
SHORT TERM...BARNES  
LONG TERM...BARNES  
AVIATION...BAK  
 
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