506
FXUS63 KILX 031937
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
137 PM CST SAT JAN 3 2026
KEY MESSAGES
- WORK WEEK HIGH TEMPERATURES IN THE 50S WILL BE ABOUT 15-20
DEGREES ABOVE EARLY JANUARY NORMALS.
- BENEFICIAL RAIN IS EXPECTED IN THE THURSDAY-FRIDAY TIME FRAME,
WITH AROUND A 25-30% CHANCE OF SEEING MORE THAN AN INCH OF
ACCUMULATION SOUTH OF I-70. HOWEVER, CHANCES OF SEEING AT LEAST
HALF AN INCH ARE AT LEAST 50% OVER EAST CENTRAL ILLINOIS, WHERE
THE ONGOING DROUGHT IS MOST SEVERE.
DISCUSSION
ISSUED AT 137 PM CST SAT JAN 3 2026
AN ELONGATED AREA OF HIGH PRESSURE CONTINUES TO EDGE SOUTHEAST
TOWARD THE FORECAST AREA EARLY THIS AFTERNOON. ALTOCUMULUS HAS
BEEN FAIRLY PERSISTENT TODAY, THOUGH AN EXPANDING AREA OF CLEARING
IS OCCURRING FROM MISSOURI TO JUST SOUTH OF THE I-72 CORRIDOR,
AND ADDITIONAL CLOUDS HAVE BEEN BREAKING UP SOME AS THEY PUSH
FURTHER SOUTHEAST INTO CENTRAL ILLINOIS. THIS TREND SHOULD
CONTINUE THE REST OF THE AFTERNOON, BEFORE LOWER CLOUDS UPSTREAM
PUSH SOUTHEAST THIS EVENING. HOWEVER, THE NET EFFECT SHOULD BE
PARTLY CLOUDY CONDITIONS OVERNIGHT INTO SUNDAY MORNING, BEFORE AN
INCREASE IN CLOUDS AGAIN ON SUNDAY.
GENERAL TRENDS FOR THE NEW FORECAST HAVE NOT CHANGED TOO MUCH FROM
THE LAST FEW MODEL RUNS. A SIGNIFICANT WARMING TREND WILL TAKE
PLACE EARLY IN THE NEW WEEK, WITH HIGHS IN THE 50S COMMON THROUGH
THE WORK WEEK. A SHORTWAVE IS PROJECTED TO TRACK ACROSS THE
MISSISSIPPI VALLEY ON TUESDAY. MOST OF THE FOCUS FOR PRECIPITATION
APPEARS CLOSER TO THE GREAT LAKES. HOWEVER, NAM/GFS FORECAST
SOUNDINGS CONTINUE TO SHOW AMPLE MOISTURE BELOW 5,000 FEET,
THOUGH SIGNIFICANTLY DRIER ABOVE. IN THE WARM ADVECTION PATTERN,
THIS MAY BE ENOUGH TO PRODUCE SOME DRIZZLE, THOUGH NOT ENOUGH
CONFIDENCE OR SIGNIFICANCE TO WARRANT ADDING INTO THE FORECAST
THIS FAR OUT.
THE MAIN FORECAST CONCERN WILL BE WITH THE LARGER STORM SYSTEM
FORMING OVER THE SOUTHERN PLAINS ON THURSDAY, AS A SIGNIFICANT
UPPER TROUGH DIGS SOUTH ACROSS THE ROCKIES. STRONG MOISTURE
ADVECTION TAKES PLACE, AS LREF GRAND ENSEMBLE PRECIPITABLE WATER
VALUES RISE TO AROUND 0.9 INCHES NEAR THE I-70 CORRIDOR BY LATE
THURSDAY AFTERNOON (ABOVE THE 90TH PERCENTILE FOR EARLY JANUARY
SOUNDING CLIMATOLOGY). THE GFS AND ITS ENSEMBLES ARE MORE BULLISH
ON GETTING RAIN IN HERE DURING THE DAY ON THURSDAY, WHILE THE
EUROPEAN COUNTERPARTS ARE LEANING MORE TOWARD AN EVENING ARRIVAL.
THERE IS ALSO SOME TIMING DIFFERENCES PERSISTING WITH THE SURFACE
LOW RIDING ALONG THE FRONT, TIED TO THE STRENGTH OF THE DIGGING
TROUGH. THUS, THERE REMAINS SIGNIFICANT UNCERTAINTY WITH THE
POTENTIAL FOR ANY STRONGER STORMS, THOUGH 100-150 J/KG OF MUCAPE
SOUTH OF I-70 WOULD AT LEAST SUGGEST A COUPLE RUMBLES OF THUNDER.
THE PWAT VALUES HELP POINT TOWARD A DECENT RAINFALL, WITH LREF
PROBABILITIES OF OVER AN INCH OF RAIN AROUND 25-30% SOUTH OF I-70,
AND THE NBM A TOUCH BELOW THAT. WORST OF THE DROUGHT REMAINS OVER
EAST CENTRAL ILLINOIS, THOUGH PROBABILITIES OF A HALF INCH ARE
AROUND 50% OR SO IN THAT AREA.
GEELHART
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1100 AM CST SAT JAN 3 2026
VFR CONDITIONS WILL PREVAIL THE NEXT 24 HOURS. EARLY AFTERNOON
CEILINGS WILL BE AROUND 10KFT, DROPPING DOWN TO AROUND 6KFT EARLY
EVENING BEFORE SCATTERING OUT. NORTH/NORTHWEST WINDS WILL REMAIN
LIGHT, BUT SWITCH TO THE SOUTHEAST SUNDAY MORNING.
GEELHART
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
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