354  
FXUS63 KILX 192333  
AFDILX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LINCOLN IL  
633 PM CDT MON APR 19 2021  
   
SYNOPSIS
 
 
ISSUED AT 324 PM CDT MON APR 19 2021  
 
A COLD FRONT WILL DEPART TO THE SOUTH OF THE AREA THIS EVENING.  
SPOTTY RAIN SHOWERS WILL OCCUR WELL BEHIND THE FRONT, MAINLY  
NORTH OF PEORIA THIS EVENING. AS COLDER AIR CONTINUES TO FILTER  
IN, THE RAIN IS EXPECTED TO CHANGE TO SNOW LATE TONIGHT AND  
TUESDAY, WITH SOME SNOW ACCUMULATION POSSIBLE. MOST OF ANY SNOW  
ACCUMULATION WILL BE ON GRASSY AND ELEVATED SURFACES, BUT SOME  
SLIPPERY ROAD CONDITIONS ARE POSSIBLE DURING THE HEAVIEST SNOW  
SHOWERS. UNSEASONABLY COLD AIR WILL PERSIST OVER THE REGION  
THROUGH MID-WEEK, WITH LOWS LIKELY DROPPING BELOW FREEZING BOTH  
TUESDAY NIGHT AND WEDNESDAY NIGHT.  
 

 
   
SHORT TERM
 
(THIS EVENING THROUGH TUESDAY)  
ISSUED AT 320 PM CDT MON APR 19 2021  
 
WINTER APPEARS TO BE MAKING IT'S LAST GASP THROUGH THURSDAY.  
 
IN THE SHORT TERM, THE COLD FRONT HAS PUSHED ACROSS HALF OF OUR  
CWA, AND IT WILL CONTINUE TO ADVANCE INTO SOUTHEAST IL THIS  
EVENING. GUSTY NW WINDS BEHIND THE FRONT WILL SUBSIDE A BIT THIS  
EVENING, BUT REMAIN STEADY.  
 
THE PRECIP WITH THIS SYSTEM WILL BE WELL BEHIND THE FRONT, AND  
WILL GENERALLY BE ON THE LIGHT SIDE. THE DRY LOW LEVEL AIR HAS  
KEPT PRECIP AT BAY FOR NEARLY OUR ENTIRE AREA, EXCEPT FOR THE FAR  
NORTHERN PORTIONS OF KNOX, STARK AND MARSHALL COUNTIES. THAT TREND  
WILL CONTINUE TONIGHT FOR THE MOST PART. A MUCH STRONGER  
FRONTOGENETICAL CIRCULATION WILL DEVELOP TUESDAY MORNING AND  
AFTERNOON, AS A SURFACE LOW PASSES BY JUST SOUTH OF ILLINOIS. THE  
BAND OF FORCING WILL SHIFT SOUTHEAST ACROSS THE AREA ON TUESDAY.  
COLUMN STRETCHING/COOLING WITH THAT PERIOD OF OMEGA SHOULD BE  
SUFFICIENT TO CHANGE THE PRECIP OVER TO ALL SNOW FOR A FEW HOURS  
DURING THE DAY ON TUESDAY, WHICH WILL RESULT IN SNOW ACCUMULATION  
ON GRASSY AND ELEVATED SURFACES. THE FLAKES COULD BE BIG ENOUGH TO  
CAUSE SOME SLIPPERY/SLUSHY CONDITIONS ON AREA ROADWAYS ON  
TUESDAY, SO SOME IMPACTS COULD OCCUR. THE BETTER CHANCES OF SNOW  
ACCUM LOOK TO BE NORTH OF I-70, WHERE GRASSY ACCUMS OF 1-2 INCHES  
WILL BE POSSIBLE. THIS IS A LATE SEASON EVENT, WHICH SOMETIMES  
WARRANTS A WINTER WEATHER HEADLINE. DUE TO EXPECTED LIMITED  
IMPACTS ON AREA ROADS FOR THE MOST PART, WE COLLABORATED TO HOLD  
OFF FOR NOW.  
 
LOW TEMPS TONIGHT WILL DIP INTO THE MIDDLE 30S, BUT CLOUD COVER  
AND STEADY WINDS WILL HELP TO LIMIT ANY FROST POTENTIAL. HIGHS  
TOMORROW COULD BE LIMITED TO RECORD COLD HIGH TEMPS IN THE MID TO  
UPPER 30S, AS OUTLINED IN THE CLIMATE SECTION OF THE AFD BELOW.  
   
LONG TERM
 
(TUESDAY NIGHT THROUGH MONDAY)  
ISSUED AT 320 PM CDT MON APR 19 2021  
 
TUESDAY NIGHT WILL SEE FREEZING TEMPS ACROSS THE BOARD, WITH  
WIDESPREAD UPPER 20S FORECAST. FROST SHOULD BE LIMITED BY HOW LATE  
THE CLOUDS CLEAR OUT, BUT FREEZING CONDITIONS COULD STILL DAMAGE  
SENSITIVE VEGETATION. PRECIPITATION WILL BE ENDING DURING THE  
EVENING, BUT A PERIOD OF SNOWFALL EAST OF SHELBYVILLE TO  
CHAMPAIGN COULD PRODUCE LIGHT SNOW ACCUMS ON GRASSY AND/OR  
ELEVATED SURFACES. GROUND TEMPS IN THAT AREA ARE EVEN WARMER THAN  
W OF I-55, SO ROADS SHOULD MELT THE SNOW AS IT FALLS TUESDAY  
EVENING.  
 
PERIODS OF SUNSHINE ON WEDNESDAY WILL HELP HIGH TEMPS RECOVER INTO  
THE UPPER 40S TO LOW 50S. DIURNAL CLOUDS WILL DEVELOP IN THE  
HEATING OF THE DAY, SO AFTERNOON SUNSHINE WILL DIMINISH. HOWEVER,  
THOSE CLOUDS WILL CLEAR OUT WED EVE, SETTING THE STAGE FOR ANOTHER  
NIGHT OF FREEZING CONDITIONS. LIGHTER WINDS AND CLEAR SKIES LATE  
WED NIGHT WE BE A BETTER SETUP FOR FROST TO DEVELOP ON OUTDOOR  
OBJECTS. ANOTHER FROST/FREEZE HEADLINE WILL LIKELY BE NEEDED FOR  
WED NIGHTS COLD CONDITIONS.  
 
TEMPERATURES WILL BEGIN WARMING ON THURSDAY AS THE COLD SURFACE  
HIGH PRESSURE CENTER DEPARTS TO TOWARD THE EAST COAST. SOUTHERLY  
LOW-MID LEVEL FLOW WILL BRING INCREASING MOISTURE AS WELL. RAIN  
SHOWER CHANCES WILL INCREASE LATER THUR NIGHT INTO FRIDAY FROM  
WEST TO EAST, WITH LIKELY RAIN SOUTH OF I-72 FRIDAY NIGHT.  
RAINFALL AMOUNTS LOOK TO REMAIN AROUND 0.25" FOR THE MOST PART, AS  
THUNDERSTORM ACTIVITY SHOULD REMAIN SOUTH OF OUR FORECAST AREA.  
 
SATURDAY WILL SEE RAIN DEPARTING TO THE EAST, BUT A WET MORNING IS  
STILL POSSIBLE. SUNDAY AND MONDAY LOOK TO BE NICE SPRING DAYS,  
WITH HIGHS IN THE MID 60S SUNDAY AND LOWER 70S MONDAY UNDER PLENTY  
OF SUNSHINE.  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)  
ISSUED AT 633 PM CDT MON APR 19 2021  
 
COLD FRONT HAS SETTLED SOUTH OF THE CENTRAL ILLINOIS TERMINALS  
EALRY THIS EVENING...WITH ALL SITES REPORTING GUSTY NW WINDS. THE  
GUSTS WILL SUBSIDE OVER THE NEXT COUPLE OF HOURS, FOLLOWED BY A  
CONTINUATION OF N/NW WINDS OF 8-12KT THROUGH THE REMAINDER OF THE  
00Z TAF PERIOD. CLOUDS WILL CONTINUE TO THICKEN/LOWER TONIGHT:  
HOWEVER, MOST FORECAST GUIDANCE SUGGESTS MVFR CEILINGS AND STEADY  
PRECIP HOLDING OFF UNTIL EARLY TUESDAY MORNING. BASED ON LATEST  
HRRR, HAVE INTRODUCED -RA/SN AT KPIA BY 10Z...THEN FURTHER E/SE TO  
KDEC AND KCMI BY 14Z. ONCE THE PRECIP BEGINS, CEILINGS WILL  
QUICKLY LOWER TO MVFR AND REMAIN THERE THROUGH THE BALANCE OF THE  
DAY. PRECIP TYPE WILL INITIALLY BE A RAIN/SNOW MIX, BUT WILL  
LIKELY CHANGE TO ALL SNOW FOR SEVERAL HOURS...BEFORE GOING BACK TO  
A RAIN/SNOW MIX BY MID TO LATE AFTERNOON.  
 

 
   
CLIMATE
 
 
ISSUED AT 255 AM CDT MON APR 19 2021  
 
RECORD LOW HIGH 4/20 RECORD LOW 4/21  
 
PEORIA.......37/1918.................28/1943  
 
SPRINGFIELD..38/1918.................28/1904  
 
LINCOLN......38/1918.................28/1982  
 
GALESBURG....39/2013.................23/1904  
 
DECATUR......43/1959.................27/1901  
 
URBANA.......43/1978.................26/1904  
 

 
   
ILX WATCHES/WARNINGS/ADVISORIES
 
 
FREEZE WARNING FROM 1 AM TO 9 AM CDT WEDNESDAY FOR ILZ027>031-  
036>038-040>057-061>063-066>068-071>073.  
 

 
 

 
 
SYNOPSIS...SHIMON  
SHORT TERM...SHIMON  
LONG TERM...SHIMON  
AVIATION...BARNES  
CLIMATE...25  
 
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