194  
FXUS63 KILX 160255  
AFDILX  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE LINCOLN IL  
855 PM CST SUN DEC 15 2024  
   
KEY MESSAGES
 
 
- THERE IS A LOW CHANCE THAT FOG REDEVELOPS THIS EVENING IN WEST-  
CENTRAL ILLINOIS.  
 
- RAIN CHANCES RETURN LATE TONIGHT INTO MONDAY WITH THE BEST  
COVERAGE FOR PRECIPITATION OVER SOUTHERN PARTS OF THE STATE.  
 
- MILD TEMPERATURES WILL RETURN TO SEASONAL NORMALS BY MIDWEEK,  
THEN TURN MUCH COLDER LATE IN THE WEEK INTO THE WEEKEND.  
 

 
   
UPDATE
 
 
ISSUED AT 850 PM CST SUN DEC 15 2024  
 
THIS EVENING, DEW POINTS INTO THE MID 30S TO LOWER 40S ARE BEING  
ADVECTED ACROSS CENTRAL ILLINOIS WHICH IS RESULTING IN SOME FOG  
DEVELOPMENT ACROSS THE REGION. PORTIONS OF EAST CENTRAL ILLINOIS  
IN PARTICULAR HAVE SEEN SOME OF THE MOST DENSE FOG SO FAR WITH  
SEVERAL SITES AND WEBCAMS SHOWING VISIBILITY OF A QUARTER MILE OR  
LESS. CAMS ARE STRUGGLING TO PICK UP ON THE EXTENT OF THE FOG THIS  
EARLY IN THE EVENING, BUT MOST HAVE FOG EXPANDING IN COVERAGE  
OVERNIGHT. HAVE HOISTED A DENSE FOG ADVISORY FOR PORTIONS OF EAST  
CENTRAL ILLINOIS THROUGH 3AM, BUT WILL NEED TO MONITOR CONDITIONS  
OVERNIGHT TO SEE IF ANY ADDITIONAL COUNTIES MAY NEED TO BE ADDED.  
NON-DIURNAL TEMPERATURE TRENDS WITH WARMING TEMPS OVERNIGHT AND  
SCATTERED SHOWERS THAT MAY HELP TO CHURN UP THE FOG AT TIMES ADD  
SOME UNCERTAINTY TO FOG TRENDS THROUGH THE EVENING.  
 
DEUBELBEISS  
 

 
   
DISCUSSION
 
 
ISSUED AT 245 PM CST SUN DEC 15 2024  
 
WATER VAPOR IMAGERY THIS AFTERNOON SHOWS AN UPPER LOW POSITIONED  
OVER THE SOUTHERN GREAT LAKES REGION WITH ANOTHER TROUGH IN THE  
NORTHERN PLAINS. AT THE SURFACE, RIDGING IS IN PLACE OVER MOST OF  
THE EASTERN US, WITH AN OPEN TROUGH/REMNANTS OF A SURFACE LOW OVER  
NORTHERN IL/WISCONSIN. LOW-LEVEL MOISTURE/STRATUS BLANKETS MOST OF  
THE AREA, REMAINING TRAPPED BENEATH A TEMPERATURE INVERSION. SOME  
CLEARING IS NOTED FROM CENTRAL MISSOURI INTO SOUTHERN ILLINOIS,  
INCHING NORTHWARD AT A GOOD PACE. HOWEVER, A WARM FRONT WILL QUICKLY  
LIFT NORTH THIS EVENING AND FILL LOW STRATUS BACK IN.  
 
CONFIDENCE REMAINS LOW FOR FOG DEVELOPMENT GOING INTO THIS EVENING.  
SURFACE OBSERVATIONS ACROSS EASTERN IOWA AND FAR NORTHEAST MISSOURI  
SHOW SPORADIC SUB 1 MILE VISIBILITIES, WITH THE HIGH RESOLUTION  
GUIDANCE SHOWING SOME OF THIS BUILDING INTO COUNTIES WEST OF THE  
ILLINOIS RIVER THIS EVENING. THAT BEING SAID, GUIDANCE ISN'T  
INITIALIZING CURRENT CONDITIONS PARTICULARLY WELL. IF FOG DOES  
REDEVELOP, IT SHOULDN'T LAST TOO LONG AS WINDS PICK UP AS THE  
PRESSURE GRADIENT TIGHTENS AHEAD OF THE APPROACHING SYSTEM.  
 
PRECIPITATION CHANCES INCREASE LATE TONIGHT INTO MONDAY MORNING AS  
SCATTERED RAIN SHOWERS DEVELOP IN A WING OF MOISTURE TRANSPORT AHEAD  
OF A COLD FRONT. TEMPERATURES WILL NON-DIURNALLY WARM OVERNIGHT,  
WITH LOWS EXPECTED TO BE MET THIS EVENING AND DAYTIME HIGHS ON  
MONDAY PEAKING IN THE MIDDLE 40S NEAR GALESBURG TO LOW 60S IN  
LAWRENCEVILLE. DEEP MOISTURE WILL STRUGGLE TO SPREAD TOO FAR NORTH,  
WITH THE BEST CHANCE FOR PRECIPITATION REMAINING IN SOUTHERN PARTS  
OF THE STATE WHERE A FEW STORMS COULD ALSO BE SEEN. IN FACT, DUE TO  
SHALLOWER MOISTURE COLUMNS FURTHER NORTH, FORECAST SOUNDINGS  
INDICATE DRIZZLE BEING MORE FAVORED NORTH OF I-72, WHICH COULD LEAD  
TO YET ANOTHER PERIOD OF REDUCED VISIBILITIES INTO MONDAY MORNING.  
RAIN AMOUNTS WILL BE HIGHEST IN SOUTHEAST ILLINOIS WHERE 0.25 TO  
0.50 INCH ARE POSSIBLE, WITH AMOUNTS GENERALLY LESS THAN 0.10" NORTH  
OF I-72.  
 
TEMPERATURES COOL BACK TO SEASONAL NORMALS GOING INTO MIDWEEK.  
ANOTHER CHANCE FOR LIGHT PRECIPITATION ARRIVES TUESDAY NIGHT INTO  
WEDNESDAY TIED TO A LOW LIFTING THROUGH THE OHIO VALLEY, WITH  
PERHAPS A BRIEF WINTRY MIX OF RAIN AND SNOW POSSIBLE ON THE TAIL END  
AS TEMPERATURES BEGIN TO COOL. FLOW ALOFT TURNS NORTHWESTERLY LATE  
IN THE WEEK, BRINGING MUCH COLDER TEMPERATURES FRIDAY THROUGH THE  
WEEKEND. ANOTHER SYSTEM WILL DIVE SOUTHEAST INTO THE UPPER MIDWEST  
STATES THURSDAY NIGHT INTO FRIDAY, WITH TEMPERATURES COLD ENOUGH  
TO SUPPORT WINTRY PRECIPITATION. GUIDANCE CONTINUES TO KEEP BETTER  
CHANCES FOR ACCUMULATING SNOW WITH THIS SYSTEM NORTH OF HERE FOR  
NOW, BUT THE LOW TRACK HAS TRENDED FURTHER SOUTH IN THE LAST FEW  
RUNS AND BEARS WATCHING.  
 
NMA  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)  
ISSUED AT 545 PM CST SUN DEC 15 2024  
 
SOUPY CONDITIONS ARE IN STORE ACROSS CENTRAL ILLINOIS AS LOW  
PRESSURE LIFTS ACROSS THE UPPER MIDWEST OVERNIGHT AND A COLD FRONT  
MOVES ACROSS CENTRAL ILLINOIS MONDAY. IFR OR LOW MVFR CONDITIONS  
ARE CURRENTLY IN PLACE, AND WHILE THERE MAY BE SOME PATCHY NEAR  
TERM IMPROVEMENT, SHOWERS AND LOW CEILINGS ARE EXPECTED TO  
OVERSPREAD CENTRAL ILLINOIS LATE THIS EVENING AND OVERNIGHT  
FOLLOWED BY A PERIOD OF DRIZZLE AND FOG WITH LIFR CONDITIONS.  
WINDS WILL VEER TO THE SOUTHWEST THEN WEST WITH PASSAGE OF A COLD  
FRONT MONDAY MORNING AND ANTICIPATE SOME IMPROVEMENT BACK TO AT  
LEAST MVFR MONDAY AFTERNOON WITH SOME CLEARING POSSIBLE IN THE  
WEST LATE IN THE PERIOD.  
 
DEUBELBEISS  
 

 
   
ILX WATCHES/WARNINGS/ADVISORIES
 
 
DENSE FOG ADVISORY UNTIL 3 AM CST MONDAY FOR ILZ044>046-053>057-  
061>063-066-067.  
 

 
 

 
 
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