243
FXUS63 KILX 071721
AFDILX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE LINCOLN IL
1121 AM CST FRI NOV 7 2025
KEY MESSAGES
- CONDITIONS TURN SHARPLY COLDER FOR SUNDAY-MONDAY, WITH HIGHS IN
THE MID 30S TO LOW 40S AND LOWS IN THE LOW 20S. BREEZY NORTHWEST
WINDS WILL RESULT IN WIND CHILL VALUES AS LOW AS 10 DEGREES
EARLY MONDAY MORNING.
- RAIN IS LIKELY SATURDAY NIGHT (50-80% CHANCE). PRECIP MAY MIX
WITH OR CHANGE TO SNOW EARLY SUNDAY MORNING, BUT ACCUMULATIONS
ARE UNLIKELY (JUST A 10-20% CHANCE OF A DUSTING ON GRASSY
SURFACES).
DISCUSSION
ISSUED AT 139 AM CST FRI NOV 7 2025
EARLY FRI AM, A 998-MB SFC LOW WAS LOCATED OVER NW WI, WITH AN
ATTENDANT COLD FRONT EXTENDING SOUTHWARD. A CORRIDOR OF BROKEN
SHOWERS AND EMBEDDED RUMBLES OF THUNDER WERE ONGOING NEAR AND NW
OF THE IL RIVER AS OF 1AM/07Z. THESE SHOWERS WILL QUICKLY PROGRESS
ACROSS THE ILX CWA, WITH TIMING TOOLS SUGGESTING THE PRECIP
ARRIVES AT THE I-55 CORRIDOR BETWEEN 2-3 AM, AND THE I-57 CORRIDOR
BETWEEN 4- 5 AM. RAIN SHOULD EXIT FAR EASTERN IL BY MID-MORNING.
TODAY WILL OFFER ONE MORE DAY OF SEASONABLY WARM TEMPS, WITH HIGHS
IN THE MID 60S NW OF THE IL RIVER TO NEAR 70 SOUTH OF I-70.
BREEZY WESTERLY WINDS WILL PERSIST THROUGH THE DAY, WITH GUSTS OF
20-25 MPH.
IN THE UPPER LEVELS, A NW FLOW REGIME BETWEEN A DEEP LOW OVER THE
HUDSON BAY AND A DEVELOPING RIDGE OVER THE WEST COAST OF THE US
WILL LEAD TO ANOTHER SHORTWAVE MIGRATING ACROSS THE ILX CWA ON
SAT. FORECAST SOUNDINGS SUGGEST INCREASING MID/HIGH CLOUD COVER
BEGINNING BY SAT MORNING, BUT DRY LOW-LEVELS WILL TAKE AWHILE TO
SATURATED ENOUGH FOR ANY PRECIP AT THE SFC. THE EXPECTATION
REMAINS THAT THE MORNING WILL BE DRY, THEN PRECIP CHANCES
GRADUALLY RAMP UP DURING THE AFTERNOON, PEAKING LATE SAT EVE
(60-80% CHANCE NORTH OF I-72, 50- 60% CHANCE SOUTH OF I-72).
THE ASSOCIATED SFC LOW IS PROGGED TO TRACK RIGHT THROUGH CENTRAL
IL SAT EVE, AND AS IT SHIFTS EAST BREEZY NW WILL BEGIN ADVECTING
COOLER AIR, SETTING THE STAGE FOR A POTENTIAL MIX WITH OR
CHANGEOVER TO SNOW LATE SAT NIGHT/EARLY SUN AM. THE LATEST
ITERATION (07.00Z) OF THE NAM DEPICTS BANDED FORCING (850-MB FGEN
BAND), ALTHOUGH THIS LARGELY OCCURS AHEAD OF THE ARRIVAL OF COOLER
AIR. THIS FGEN FORCING IS ALSO POSITIONED WELL BELOW THE DGZ.
ULTIMATELY, THE PRECIP INTENSITY SEEMS TO BE WANING AS AIR
SUFFICIENTLY COOL FOR SNOW PUSHES IN. SOME SNOW COULD CERTAINLY
STILL MIX IN, BUT BETWEEN THE WEAKENING FORCING AND WARM GROUND
AFTER A WEEK OF TEMPS IN THE 60S, ACCUMULATIONS LOOK UNLIKELY.
THE LATEST GRAND ENSEMBLE HAS A 10-20% CHANCE OF A DUSTING OF SNOW
(MAINLY NORTH OF I-74). WITH THE ATMOSPHERIC COLUMN DRYING AS
TEMPS FALL, IT'S POSSIBLE WE LOSE CLOUD ICE PRIOR TO THE LINGERING
LIGHT PRECIP ENDING. THE LACK OF CLOUD ICE WOULD THEN FAVOR
LIQUID PRECIP RATHER THAN SNOW. SFC TEMPS DROP TO NEAR FREEZING BY
5-6 AM SUNDAY, SO WILL NEED TO KEEP AN EYE ON FCST SOUNDINGS FOR
A BRIEF WINDOW WHEN LIGHT FREEZING RAIN WOULD BE POSSIBLE. FOR
NOW, FCST SOUNDINGS DON'T APPEAR SATURATED ENOUGH IN THE LOW
LEVELS DURING THIS TIMEFRAME TO WARRANT A MENTION OF 'SLIGHT
CHANCE FREEZING RAIN' IN THE FORECAST. TO BE COMPLETELY CLEAR, MY
CONCERN FOR ANY FREEZING RAIN SUNDAY AM IS VERY LOW AT THIS TIME,
THIS IS SIMPLY SOMETHING TO KEEP AN EYE ON WITH THE FORECAST IN
THE COMING DAYS.
INTO SUN, THE UPPER PATTERN WILL BE HIGHLY AMPLIFIED, WITH THE
TROUGHING OVER THE EASTERN HALF OF THE US REPRESENTING 500MB
HEIGHTS THAT ARE 2-3 STANDARD DEVIATIONS BELOW THE MEAN. THIS WILL
CORRESPOND TO SHARPLY COOLER TEMPS BY SUN, WHEN HIGHS STRUGGLE TO
CLIMB ABOVE 40 DEGF. SUCH CONDITIONS ARE ROUGHLY 15 DEGF BELOW
NORMAL. BREEZY NW FLOW, WITH GUSTS TO 30 MPH DURING THE DAY SUN,
WILL RESULT IN SEASONABLY HARSH WIND CHILLS AS COLD AS 15 DEGF SUN
MORNING, WITH VALUES ONLY REACHING INTO THE 20S DURING THE
AFTERNOON. WINDS REMAIN ELEVATED INTO SUNDAY NIGHT (SUSTAINED AT
10- 15 MPH) AS AIR TEMPS FALL INTO THE LOW 20S. THAT WILL RESULT
IN MINIMUM WIND CHILL VALUES NEAR 10 DEGF EARLY MONDAY AM.
LONG, NORTHERLY FETCH OF COLD AIR OVER THE COMPARATIVELY WARM
WATERS OF LAKE MICHIGAN MEANS THAT LAKE-EFFECT SNOW IS POSSIBLE
SUN-MON. IT STILL APPEARS THAT THIS BAND WILL BE ORIENTED TOWARDS
PORTIONS OF WESTERN IN, BUT CAN'T RULE OUT SOME FLURRIES OR
PERIODS OF LIGHT SNOW (MAINLY EAST OF I-55). TEMPS STAY WELL BELOW
NORMAL ON MON, ONCE AGAIN STRUGGLING TO REACH 40 DEGF, BUT SHOULD
GRADUALLY MODERATE TOWARDS SEASONABLE VALUES BY MID-WEEK (AND
STAY SEASONABLE INTO LATE WEEK). PRIMARILY DRY CONDITIONS ARE
EXPECTED AFTER ANY LINGERING LAKE-ENHANCED SNOW DEPARTS THE AREA
SUN-MON, WITH PRECIP CHANCES BELOW 10% FROM MON PM ONWARD.
ERWIN
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1120 AM CST FRI NOV 7 2025
IN THE WAKE OF A COLD FRONT, WEST WINDS WILL GUST TO AROUND 20 KT
THROUGHOUT THE AFTERNOON BEFORE EASING AND VEERING TO A NORTHERLY
DIRECTION THIS EVENING INTO THE OVERNIGHT. BY 12Z (6AM CST)
SATURDAY, MVFR LAKE EFFECT CLOUDS OFF OF LAKE MICHIGAN MAY
ATTEMPT TO PUSH INTO BMI AND PIA, BUT THE PROBABILITY OF CEILINGS
AT EITHER TERMINAL IS LOW (20-30%).
BUMGARDNER
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
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