207
FXUS63 KILX 052034
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
234 PM CST MON JAN 5 2026
KEY MESSAGES
- A STORM SYSTEM WILL BRING RAIN TO CENTRAL ILLINOIS THURSDAY INTO
FRIDAY. THE LATEST INDICATIONS SUGGEST RAINFALL AMOUNTS IN
EXCESS OF 1 INCH.
- THUNDERSTORMS WILL BE POSSIBLE WITH THE SYSTEM...PARTICULARLY
ALONG AND SOUTHEAST OF A SPRINGFIELD TO CHAMPAIGN LINE.
- AFTER A PERIOD OF ABOVE NORMAL TEMPERATURES FOR THE NEXT SEVERAL
DAYS, READINGS WILL RETURN TO SEASONABLE VALUES IN THE 30S AND
40S BY NEXT WEEKEND.
SHORT TERM
(TONIGHT THROUGH TUESDAY)
ISSUED AT 234 PM CST MON JAN 5 2026
A SHORT-WAVE TROUGH EVIDENT ON 1930Z/130PM WATER VAPOR IMAGERY
OVER WESTERN NEBRASKA WILL TRACK EASTWARD TOWARD THE SOUTHERN
GREAT LAKES TONIGHT. WARM ADVECTION AHEAD OF THIS SYSTEM WILL LEAD
TO THE DEVELOPMENT OF WIDESPREAD CLOUD COVER AND PERHAPS SOME VERY
LIGHT PRECIPITATION. MODEL SOLUTIONS VARY...WITH SYNOPTIC MODELS
SUCH AS THE GFS KEEPING CLOUD BASES HIGH AND CONDITIONS MOSTLY
DRY. MEANWHILE HIGHER RESOLUTION MODELS LIKE THE NAM AND HRRR
SUGGEST MUCH LOWER CLOUD COVER. NAM FORECAST SOUNDINGS SHOW LOW
CLOUDS RAPIDLY DEVELOPING AFTER MIDNIGHT, WITH THE TOP OF THE MOIST
LAYER AT AROUND 5000FT ALOFT. GIVEN THE SHALLOW MOISTURE PROFILE,
AM SKEPTICAL ANY MEASURABLE PRECIP CAN OCCUR. IN ADDITION, S/SW
WINDS OF AROUND 10MPH SHOULD PROVIDE ENOUGH MIXING TO PREVENT
WIDESPREAD FOG DEVELOPMENT. HAVE OPTED INSTEAD TO MENTION PATCHY
DRIZZLE EVERYWHERE NORTH OF THE I-70 CORRIDOR LATE TONIGHT INTO
TUESDAY MORNING AS THE SHORT-WAVE AND ITS ASSOCIATED WEAK SURFACE
LOW PASS TO THE NORTH.
ONCE THE LOW TRACKS INTO THE GREAT LAKES AND A WEAK COLD FRONT
PASSES, WINDS WILL VEER TO THE WEST AND INCREASE TO 10-15MPH ON
TUESDAY. THE BIG FORECAST CHALLENGE THEN BECOMES HOW MUCH (IF ANY)
CLEARING CAN OCCUR. WHILE GFS FORECAST SOUNDINGS AND MAV GUIDANCE
INDICATE AT LEAST PARTIAL CLEARING BY AFTERNOON, NAM/HRRR
SOUNDINGS PAINT A MUCH MORE PESSIMISTIC PICTURE. GIVEN THE TIME OF
YEAR AND THE GFS BIAS OF SCOURING OUT CLOUDS TOO QUICKLY, HAVE
INCREASED SKY COVER CONSIDERABLY FROM PREVIOUS FORECASTS...RESULTING
IN CONTINUED CLOUDY SKIES THROUGH TUESDAY AFTERNOON AND EVENING
BEFORE PARTIAL CLEARING ARRIVES TUESDAY NIGHT INTO WEDNESDAY
MORNING.
BARNES
LONG TERM
(WEDNESDAY THROUGH NEXT MONDAY)
ISSUED AT 234 PM CST MON JAN 5 2026
ONCE HIGH PRESSURE SHIFTS EAST OF THE REGION AND SOUTHERLY RETURN
FLOW COMMENCES, ANY LINGERING CLOUD COVER WILL QUICKLY DEPART
WEDNESDAY MORNING...FOLLOWED BY AMPLE SUNSHINE IN THE AFTERNOON.
THANKS TO THE SUN AND S/SW WINDS, HIGHS WILL CLIMB WELL INTO THE
50S.
AS HAS BEEN ADVERTISED FOR THE PAST SEVERAL DAYS, THE NEXT BIG
RAIN-MAKER WILL ARRIVE BY THURSDAY. 12Z JAN 5 MODELS HAVE COME
INTO MUCH BETTER AGREEMENT...WITH NAM/GFS/ECMWF CONSENSUS SHOWING
LOW PRESSURE TRACKING FROM THE TEXAS/OKLAHOMA PANHANDLE REGION
THURSDAY MORNING TO NEAR LAKE ERIE BY FRIDAY MORNING. THIS PARTICULAR
TRACK TAKES THE LOW ACROSS THE HEART OF CENTRAL ILLINOIS THURSDAY
EVENING AND SETS THE STAGE FOR WIDESPREAD RAINFALL AND POTENTIAL
THUNDERSTORMS. A LOW CAPE/HIGH SHEAR ENVIRONMENT WILL BE IN PLACE,
WITH THE NAM SHOWING MUCAPE OF 50-100J/KG AND 0-6KM BULK SHEAR OF
60-70KT THURSDAY AFTERNOON/EVENING. GIVEN THE FAVORABLE KINEMATICS
AND LOW TRACK, HAVE OPTED TO ADD THUNDER TO THE FORECAST MAINLY
ALONG/EAST OF I-55. THE LATEST COLORADO STATE MACHINE LEARNING
ALGORITHM SHOWS A 5-15% CHANCE OF SEVERE ALONG/SOUTH OF A
SPRINGFIELD TO CHAMPAIGN LINE. SHOWERS AND A FEW THUNDERSTORMS
WILL BE ONGOING THURSDAY EVENING WITH THE SHOWERS BECOMING LESS
NUMEROUS OVERNIGHT.
THE LATEST MODEL SUITE TRACKS THE FIRST LOW INTO THE EASTERN GREAT
LAKES AND PUSHES A COLD FRONT THROUGH CENTRAL ILLINOIS LATE
THURSDAY NIGHT INTO FRIDAY MORNING...WITH A SECONDARY LOW FORMING
ALONG THE DEPARTING BOUNDARY FRIDAY AFTERNOON/EVENING. SOLUTIONS
STILL VARY CONSIDERABLY, WITH THE GFS KEEPING ANY ADDITIONAL
PRECIP TO THE SOUTH ACROSS THE OHIO RIVER VALLEY AND THE ECMWF
SHOWING LIGHT RAIN IN CENTRAL ILLINOIS. AT THIS TIME, WILL
MAINTAIN POPS FRIDAY INTO FRIDAY NIGHT...BUT THESE MAY NEED TO BE
ADJUSTED AND/OR REMOVED DEPENDING ON HOW FAR S/SE THE FRONT DROPS
BEFORE THE SECOND LOW FORMS. BY THE TIME ALL THE RAIN COMES TO AN
END, AMOUNTS WILL REACH 1 INCH OR MORE ACROSS ALL OF CENTRAL AND
SOUTHEAST ILLINOIS.
AFTER THE SECOND LOW EXITS, A COLDER AIRMASS WILL SETTLE INTO THE
REGION THIS WEEKEND. HIGHS WELL INTO THE 50S (AND PERHAPS OVER 60
ACROSS THE E/SE KILX CWA) ON FRIDAY WILL DROP INTO THE LOWER TO
MIDDLE 30S BY SUNDAY.
BARNES
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1142 AM CST MON JAN 5 2026
LOW PRESSURE WILL TRACK ACROSS NORTHERN ILLINOIS TONIGHT...BRINGING
LOW CLOUDS AND DRIZZLE TO THE AREA. LATEST CAMS MAINTAIN VFR CONDITIONS
UNTIL MIDNIGHT, THEN CEILINGS/VISBYS DETERIORATE OVERNIGHT. BASED ON
HRRR/RAP OUTPUT, HAVE INTRODUCED MVFR AT KPIA BY 08Z THEN FURTHER
EAST TO KBMI/KDEC/KCMI BY 10Z. ONCE THE WAVE PASSES, THE DRIZZLE
WILL COME TO AN END FROM WEST TO EAST BY TUESDAY MORNING: HOWEVER,
LOW CLOUDS WILL PERSIST THROUGH 18Z. WINDS WILL INITIALLY BE S/SW
AT 5-10KT THIS AFTERNOON, THEN WILL TEMPORARILY BACK TO SE TOWARD
SUNSET. AS THE LOW APPROACHES, WINDS WILL BECOME SW LATE THIS
EVENING, THEN WILL VEER TO W AND INCREASE TO 10-15KT AFTER FROPA
BY MID-MORNING MONDAY.
BARNES
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
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