446
FXUS63 KILX 041133
AFDILX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE LINCOLN IL
533 AM CST SUN JAN 4 2026
KEY MESSAGES
- MILD CONDITIONS ARE FORECAST DURING THE WORK WEEK WITH DAILY
HIGHS GENERALLY IN THE 50S.
- AMIDST PERSISTENT DROUGHT CONDITIONS, THE BEST OPPORTUNITY FOR
BENEFICIAL RAIN WILL BE THURSDAY INTO FRIDAY. CHANCES FOR MORE
THAN A HALF INCH OF RAINFALL RANGE FROM 40-50% SOUTH OF I-70 TO
20-30% IN WEST-CENTRAL IL.
DISCUSSION
ISSUED AT 135 AM CST SUN JAN 4 2026
***** SEASONABLY COOL TODAY *****
SURFACE HIGH PRESSURE SPRAWLED OVER THE MIDWEST CONTINUES TO
MAINTAIN TRANQUIL CONDITIONS OVER THE FORECAST AREA THIS MORNING,
WHILE SUBSIDENCE ASSOCIATED WITH UPSTREAM RIDGING HAS COMPRESSED
BOUNDARY LAYER MOISTURE AND RESULTED IN WIDESPREAD LOW CLOUDS. THE
NBM AND NAM, WHICH ARE HANDLING THIS STRATUS BEST, SUGGEST IT'LL
RETREAT NORTHWARD AS LOW LEVEL WARM ADVECTION DEVELOPS ACROSS THE
AREA THIS AFTERNOON. THOUGH MID-HIGH CLOUDS WILL PERSIST, EVEN THE
FILTERED SUNSHINE SHOULD BE SUFFICIENT TO WARM AREAS SOUTH OF A
ROUGHLY MACOMB TO ROBINSON LINE TO 40+, WHILE TEMPERATURES TOP OUT
IN THE MID 30S NORTH OF I-74. WE'LL HAVE TO WATCH OUT FOR SOME FOG
DEVELOPING IN WEST-CENTRAL IL BY EARLY TOMORROW MORNING AS TEMPS
DROP WITH DEPARTING MID-HIGH CLOUDS AND MOISTURE ADVECTION
PERSISTS; HREF SUGGESTS 15-30% CHANCES FOR VISIBILITIES LESS THAN
1/2 MILE WEST OF THE IL RIVER BY 6AM TOMORROW.
***** CLOUDY BUT MILD MONDAY INTO TUESDAY *****
WHEREVER THIS FOG AND/OR LOW STRATUS LINGERS (MOST LIKELY WEST OF
THE IL RIVER), TEMPERATURES ON MONDAY MAY RUN A LITTLE COOLER THAN
GUIDANCE, BUT FURTHER SOUTH EXPECT HIGHS TO CLIMB INTO THE 50S.
WARM, MOIST ADVECTION WILL CONTINUE TOMORROW NIGHT, AND AS A RESULT
ANOTHER ROUND OF, PERHAPS MORE WIDESPREAD, LOW CLOUDS, FOG, AND/OR
DRIZZLE SEEM PLAUSIBLE. BOTH THE NAM AND GFS ADVERTISE NEGLIGIBLE
PROBABILITIES OF CLOUD ICE, NEGATIVE OMEGA (UPWARD MOTION) AND NEAR
SATURATION (RH > 85%) IN THE LOWEST 1KM, WITH THE NAM ALSO
ADVERTISING DIMINISHED VISIBILITY (< 1 MILE) AND LIGHT QPF (T -
0.03") NORTH OF ROUGHLY I-72. TEMPS SHOULD BE TOO WARM FOR ANY
DRIZZLE TO FREEZE, SO WHILE THERE COULD BE IMPACTS IF FOG BECOMES
DENSE, CONFIDENCE WAS TOO LOW TO MAKE THOSE CHANGES TO THE
FORECAST AT THIS TIME.
***** RAIN CHANCES (40-60%) CLOSE THE WORK WEEK *****
CONDITIONS ARE FORECAST TO REMAIN MILD THROUGH AT LEAST THURSDAY,
AFTER WHICH TIME RIDGING WILL BEGIN TO SHIFT EAST AS A MORE POTENT
UPPER LEVEL TROUGH APPROACHES. GLOBAL MODELS AND THEIR RESPECTIVE
ENSEMBLES CONTINUE TO DIFFER DRAMATICALLY IN THE EVOLUTION AND TRACK
OF A SURFACE LOW DEVELOPING IN THE LEFT EXIT REGION OF A 100+ KT
500MB JET STREAK. FOR EXAMPLE, THE CURRENT GFS HAS THE SURFACE LOW
TRACKING ALONG THE OHIO RIVER TO KEEP OUR AREA COOL AND DRY, WHILE
THE ECMWF HAS THE LOW LIFTING NORTH ALONG THE MISSISSIPPI RIVER INTO
THE IA/IL/WI TRISTATE AREA - WHICH WOULD BRING OUR AREA SUFFICIENT
MOISTURE AND WARMTH FOR A BENEFICIAL RAINFALL AND PERHAPS SOME
THUNDERSTORMS LATE THURSDAY INTO FRIDAY. FOR WHAT IT'S WORTH, RAW
ENSEMBLE GUIDANCE (LREF) GIVES 40-50% CHANCES FOR MORE THAN A HALF
INCH OF RAINFALL OVER SOUTHEAST IL, WITH THOSE PROBABILITIES
TAPERING TO 20-30% WEST OF THE IL RIVER IN WEST-CENTRAL IL. BEHIND
THIS SYSTEM, CONDITIONS WILL TURN SEASONABLY COLD AND BREEZY ONCE
AGAIN.
BUMGARDNER
AVIATION
(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 532 AM CST SUN JAN 4 2026
A SEA OF MVFR STRATUS REMAINS OVER THE AIRFIELDS THIS MORNING,
THOUGH A FEW HOLES ARE BEGINNING TO DEVELOP, INCLUDING ONE WHICH
MIGHT BRIEFLY IMPACT PIA AT SOME POINT OVER THE NEXT 1-3 HOURS.
NBM AND GLAMP SUGGEST THESE CLOUDS WILL RETREAT NORTH AND EXIT THE
TERMINALS AROUND MIDDAY AS WINDS, INITIALLY OUT OF THE NORTH,
FLIP AROUND AND BECOME SOUTHERLY AS SURFACE HIGH PRESSURE SHIFTS
OFF TO THE EAST.
BUMGARDNER
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
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