723
FXUS63 KLOT 282103 CCA
AFDLOT
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
303 PM CST SUN DEC 28 2025
KEY MESSAGES
- THERE IS A THREAT FOR A FEW SEVERE THUNDERSTORMS CAPABLE OF
DAMAGING WINDS AND POSSIBLY A COUPLE OF TORNADOES THIS
AFTERNOON, PRIMARILY SOUTH OF I-80 AND EAST OF I-55. A TORNADO
WATCH HAS BEEN ISSUED FOR SOUTHERN PORTIONS OF THE CWA.
- A WIND ADVISORY IS IN EFFECT DUE TO THE EXPECTED POWERFUL
WINDS, GUSTING OVER 50 MPH AT TIMES, TONIGHT INTO MONDAY
MORNING AREAWIDE. GUSTS MAY REACH 55 TO 60+ MPH AT TIMES IN
NORTHERN PORTER COUNTY, INDIANA AS STRONGER WINDS MOVE OFF OF
LAKE MICHIGAN.
- WIND WHIPPED SNOW SHOWERS AND FLURRIES ARE EXPECTED LATE
TONIGHT INTO MONDAY MORNING, ESPECIALLY NORTH OF I-88/I-290
WHERE A COATING TO LOCALLY AN INCH OF ACCUMULATION COULD
RESULT IN HAZARDOUS TRAVEL.
- TEMPERATURES WILL PLUMMET BEHIND A COLD FRONT THIS EVENING.
EXPECT WIND CHILLS CLOSE TO ZERO MONDAY MORNING.
DISCUSSION
ISSUED AT 240 PM CST SUN DEC 28 2025
THROUGH MONDAY:
HEAVY RAIN AND THUNDERSTORMS ARE ON A BREAK HERE LOCALLY DURING
THE EARLY AFTERNOON AFTER AN EVENTFUL MORNING. WIDESPREAD LIGHT
TO MODERATE RAIN IMPACTED MOST OF OUR CWA AND WE SAW A CORRIDOR
OF MOSTLY SUB-SEVERE THUNDERSTORMS NEAR AND SOUTH OF I-80. ONE
LONE SEVERE STORM MANAGED TO PRODUCE SOME NOTEWORTHY WIND DAMAGE
IN LIVINGSTON COUNTY. WE ALSO RECEIVED A HANDFUL OF REPORTS OF
STREET FLOODING. IT APPEARS THAT OVER HALF AN INCH OF RAIN FELL
AROUND A BIG MAJORITY OF OUR CWA THIS MORNING WITH A SIZABLE
CORRIDOR OF 1-2" NEAR AND SOUTH OF I-80. HERE IN ROMEOVILLE,
WE'VE RECEIVED OVER 1.1" SINCE THIS MORNING.
LIGHTER, DENSELY SCATTERED SHOWERS NOW CONTINUE NEAR AND NORTH
OF I- 80 AS OF AROUND 2 PM AS THE WARM FRONT CONTINUES TO PUSH
NORTH AHEAD OF THE APPROACHING CYCLONE. THE MUCAPE RESERVOIR
HAS NOT KEPT UP WITH THE FRONT ON ITS NORTHWARD PROGRESSION,
WHICH EXPLAINS THE ABSENCE OF THUNDER NOW.
DOWN INTO CENTRAL IL, WE'VE SEEN CONVECTIVE ACTIVITY QUICKLY
DEVELOP ALONG THE STORM'S STRENGTHENING COLD FRONT. EMBEDDED
SEVERE CONVECTION IS CROSSING THE ILLINOIS RIVER NEAR PEORIA AS
OF 2 PM. LATEST SPC MESOANALYSIS SHOWS BETWEEN 500 AND 1000 J/KG
OF SURFACE- BASED INSTABILITY IS AVAILABLE ACROSS CENTRAL IL
AND STRETCHING INTO OUR FAR SOUTHERN CWA ALONG AND AHEAD OF THE
LINE. THIS COMES AS TEMPERATURES HAVE WARMED TO NEAR 70 DEGREES
AND DEWPOINTS INTO THE LOWER 60S IN CENTRAL IL WITHIN THE
STORM'S WARM SECTOR. IT ALSO DEPICTS 30 KT OF 0-1 KM SHEAR ALONG
THIS LINE AND 50 TO 60 KT OF 0-3 KM SHEAR. THIS LINE WILL RACE
TOWARD THE EAST AT 50 TO 60 MPH THROUGH THE REMAINDER OF THE
AFTERNOON. EXPECTATIONS ARE FOR THUNDERSTORM COVERAGE TO FILL IN
ALONG THE FRONT INTO MID-AFTERNOON AS THE ACCELERATING WARM
CONVEYOR CONTINUES TO TRANSPORT MOISTURE AND INSTABILITY
NORTHWARD. THE BETTER PART OF THE CHICAGO METRO COULD BE IN FOR
ADDITIONAL ELEVATED STORMS NEAR AND SOUTH OF THE STORM'S TRIPLE
POINT. BUT THE MORE APPRECIABLE INGREDIENTS FOR SEVERE
CONVECTION STILL LOOK TO FAVOR AREAS ROUGHLY ALONG AND EAST OF
I-55 AND SOUTH OF I-80 DURING THE LATTER HALF OF THE AFTERNOON.
PRIMARY SEVERE HAZARDS WILL BE DAMAGING WIND GUSTS TO 60 TO 70
MPH AND A FEW TORNADOES. THE THREAT FOR BOTH HAS INCREASED NOW
THAT SURFACE-BASED STORMS ARE BASICALLY CERTAIN. A TORNADO WATCH
WAS RECENTLY ISSUED FROM SPC IN THIS CORRIDOR. VERY HEAVY
RAINFALL IS ALSO POSSIBLE ALONG THIS LINE, BUT GIVEN THE
PROGRESSIVE NATURE OF THE FRONT, NOT REALLY ANTICIPATING MANY
FLOODING ISSUES OUTSIDE OF AREAS THAT SAW PROBLEMS EARLIER
TODAY; THOSE COULD BE RESURRECTED BY THE ADDED RAINFALL. THE
WINDOW FOR SEVERE CONVECTION IN OUR AREA LOOKS RATHER BRIEF,
ROUGHLY 3 TO 6 PM. OVER ANY GIVEN AREA, THE SEVERE THREAT WILL
ONLY LAST A HANDFUL OF MINUTES. THE LINE WILL PUSH EAST OF THE
CWA BY 6 PM.
WINDS WILL RAMP UP VERY QUICKLY IN THE WAKE OF THIS SYSTEM/COLD
FRONT LATE THIS AFTERNOON AND EVENING. MOST OF THE CWA SHOULD
BE LOOKING AT GUSTS OUT OF THE WEST AT 30 TO 35 MPH BY DUSK
BUILDING TO 45 TO 50 AREA-WIDE BY THE END OF THIS EVENING. SUCH
WINDS ARE EXPECTED THROUGH THE NIGHT AND INTO EARLY MONDAY, WITH
STEADY BUT VERY GRADUAL EASING EXPECTED DURING THE MORNING AND
AFTERNOON. NO CHANGES WERE MADE TO THE GOING WIND ADVISORY. AN
UPGRADE TO A HIGH WIND WARNING WAS CONSIDERED IN PORTER COUNTY,
IN WHERE THERE ARE CONCERNS FOR A PERIOD 60+ MPH WINDS TO
PROTRUDE INLAND OFF THE LAKE. WHILE THIS LOOKS TO BE CONFINED TO
ONLY A HANDFUL OF MILES INLAND FROM THE SHORE, THESE SORTS OF
WINDS WOULD BE MOVING OVER I-94 AND OTHER MAJOR ARTERIALS ALONG
THE LAKESHORE POSSIBLY DURING PORTIONS OF THE MORNING COMMUTE.
CONFIDENCE WASN'T QUITE THERE TO WARRANT UPGRADING YET, BUT
CONSIDERATIONS WILL STILL BE MADE.
ALSO IN THE WAKE OF THE FRONT, TEMPERATURES WILL DROP LIKE A
ROCK THIS EVENING AND TONIGHT, AS MANY AS 20+ DEGREES IN JUST A
FEW HOURS. IT'S TOUGH TO SAY THE EXTENT OF IMPACTS WE'LL SEE
FROM ANY FLASH FREEZING, BUT AT LEAST SOME SLICK SPOTS ON ROADS
APPEAR LIKELY TO FORM. ANY LINGERING PUDDLES OR PONDING WILL
FREEZE, BUT HOPEFULLY THESE WILL MOSTLY BE FOUND OFF OF
ROADWAYS. THE STRONG WINDS THIS EVENING SHOULD HELP DRY ROADS
OFF BEFORE FREEZING OVER. HOWEVER, EVEN IF NO SNOW ON THE ROADS,
BE AWARE THAT AREAS COULD BE SLIPPERY LATE TONIGHT INTO
TOMORROW. ALSO PREPARE FOR A MUCH COLDER DAY WITH MORNING WINDS
CHILLS NEAR AND BELOW ZERO, AND IN THE SINGLE DIGITS ABOVE ZERO
DURING THE AFTERNOON.
SNOW SHOWERS ARE EXPECTED TO WRAP AROUND THE LOW TO THE NORTH
AND FALL ON THE CWA THIS EVENING INTO MONDAY. THE BEST CHANCES
TO SEE TRUE SNOW SHOWERS THROUGH MOST OF TONIGHT WILL BE NORTH
OF I-80 WHERE FLURRIES WILL BE FAVORED FARTHER SOUTH. THE BETTER
PUSH OF SNOW SHOWERS APPEARS TO COME LATE DURING THE OVERNIGHT
AND INTO MONDAY MORNING AS A SECONDARY BOUNDARY PUSHES ACROSS.
FORECAST SOUNDINGS DEPICT A FEW HOUR WINDOW WHERE ADDED FORCING
FROM THIS WAVE WILL INTERACT WITH A RATHER DEEP DGZ PRESENCE AND
COULD CHURN UP SOME MODERATE SNOW AT TIMES, ESPECIALLY IN OUR
NORTHERN CWA AND AROUND LAKE MICHIGAN. THE WINDY CONDITIONS WILL
ONLY MAKE MATTERS WORSE ON THE ROADS LEADING TO BLOWING SNOW
AND POOR VISIBILITY. EVEN LIGHTER SNOWFALL WILL BRING ABOUT
HAZARDOUS TRAVEL CONDITIONS. BE PREPARED FOR SUDDEN CHANGES IN
VISIBILITY IN SNOW TONIGHT AND MONDAY MORNING, INCLUDING DURING
THE COMMUTE. SNOW MAY LINGER INTO THE AFTERNOON, MAINLY AROUND
THE LAKE AND INTO NORTHWESTERN IN WITH FLURRIES POSSIBLE
ELSEWHERE, BUT MOST OF THE AREA WILL SEE AN END TO THE IMPACTFUL
SNOW SHOWERS SOMETIME DURING THE MORNING. GUIDANCE FAVORS
AROUND AN INCH OF ACCUMULATION UP NEAR THE WI STATE LINE AND A
COUPLE TO SEVERAL TENTHS ELSEWHERE AROUND THE AREA.
DOOM
MONDAY NIGHT THROUGH SUNDAY:
THE UPPER LEVEL LOW THAT IS DRIVING THIS WEEKEND'S WEATHER WILL BE
OVER QUEBEC BY MONDAY NIGHT. ANOTHER UPPER LEVEL LOW IS EXPECTED TO
DROP SOUTHWARD FROM HUDSON BAY MONDAY NIGHT THROUGH TUESDAY. WHILE
THESE TWO UPPER LEVEL LOWS PHASE WITH EACH OTHER, IMPACTING THE
WEATHER OUT EAST, IT WILL SEND A SERIES WEAK DISTURBANCES EXTENDING
BACK OVER LAKE MICHIGAN THAT COULD PROVIDE A COUPLE ADDITIONAL
ROUNDS OF WINTRY PRECIPITATION. UNFORTUNATELY, MODELS ARE SHOWING
LITTLE AGREEMENT PROVIDING LOWER CONFIDENCE IN THE DETAILS.
THE FIRST WEAK DISTURBANCE DROPS SOUTHWARD OUT OF CANADA ON TUESDAY.
THE EURO ENSEMBLE HAS A SURFACE LOW IN SOUTH-CENTRAL CANADA DROPPING
INTO NORTHERN MINNESOTA BEFORE WEAKENING AS IT MOVES FROM THE
MINNESOTA ARROWHEAD TO MICHIGAN'S WESTERN MITTEN. THE GEFS MEANWHILE
HAS A WEAKER WAVE AND A MORE EASTERN TRACK. FOR NOW, KEPT SNOW OUT
OF THE FORECAST. MAYBE SOME FLURRIES OR LIGHT SNOW IS POSSIBLE
FOR AREAS CLOSER TO LAKE MICHIGAN, BUT UNLESS MODELS SHIFT MORE
WESTWARD, DRY CONDITIONS SHOULD PREVAIL.
MODELS HAVE SHOWN SOME DECENT AGREEMENT THAT AS THE PREVIOUSLY
MENTIONED UPPER LOWS PHASE AROUND EACH OTHER TUESDAY NIGHT INTO
WEDNESDAY, THEY WILL SLOWLY RETROGRADE WESTWARD INTO ONTARIO WITH
A STRENGTHENING 300 MB 100+ KNOT JET AND A REFLECTED DEEPENING
SURFACE CYCLONE. WITH A WEAK MID LEVEL WAVE DROPPING SOUTHWARD, A
SURFACE COLD FRONT IS EXPECTED TO PASS OVER THE AREA ON WEDNESDAY
WITH MUCH MORE ROBUST COLD AIR ADVECTION BEHIND THE FRONT. NO
CHANGES WERE MADE TO THE POPS AS LATEST NBM RUN KEEPS CHANCES FOR
SNOW FOR MUCH THE AREA. THERE IS STILL PLENTY OF MODEL
DISAGREEMENT ON EXACT TIMING AND SNOW AMOUNTS. AND WHILE CURRENT
INDICATORS ARE THAT IT DOES NOT HAVE A SIGNATURE OF A MAJOR SNOW
STORM, IT COULD PROVIDE A COATING ON THE GROUND. HOLIDAY REVELERS
MAY EXPECT SOME SNOW FALLING DOWN AS 2025 RUNS OUT OF TIME.
TEMPERATURES WILL FEEL MUCH MORE WINTER LIKE THROUGH THE WEEK. AS
NORTHWEST WINDS PERSIST THROUGH MONDAY NIGHT INTO TUESDAY MORNING,
SINGLE DIGITS TO LOW TEENS ARE EXPECTED IN THE MORNING WITH WIND
CHILLS AT OR JUST UNDER ZERO DEGREES F. HIGH TEMPERATURES ARE
EXPECTED IN THE 20S TO JUST BELOW FREEZING TUESDAY AND WEDNESDAY.
NEW YEARS DAY LOOKS TO BE A CHILLY ONE AS TEMPS DROP ONCE AGAIN
BEHIND THE FRONT. THE NBM IS SUGGESTING SOLIDLY IN THE 20S FOR
HIGHS, BUT THAT MIGHT BE BIASED BY THE GFS/GEFS HAVING NO SNOW,
WHEREAS THE EURO SUITE IS ADVERTISING HIGHS IN THE TEENS (A LIKELY
RESULT "IF" THERE IS A COATING OF SNOW ON THE GROUND).
TEMPERATURES ARE EXPECTED TO CLIMB SLOWLY BACK INTO THE UPPER 20S
AND LOW 30S FOR THE END OF THE WEEK/WEEKEND. THERE IS A CHANCE FOR
ANOTHER WINTER SYSTEM THAT COULD BRING SOME MORE PRECIP TO THE AREA,
POTENTIALLY ON SUNDAY, BUT MODELS ARE NOT SHOWING A LOT OF AGREEMENT
AT THIS DISTANCE TO HAVE GREAT CONFIDENCE.
DK
AVIATION /18Z TAFS THROUGH 00Z TUESDAY/
ISSUED AT 1211 PM CST SUN DEC 28 2025
FORECAST CONCERNS INCLUDE...
FOG, POSSIBLY DENSE, THIS AFTERNOON.
CHANCE OF THUNDERSTORMS THIS AFTERNOON.
VERY STRONG/GUSTY WESTERLY WINDS THIS EVENING INTO MONDAY.
LIGHT SNOW WITH BLOWING SNOW OVERNIGHT/EARLY MONDAY MORNING.
VISIBILITIES WITH FOG WILL REMAIN CHALLENGING UNTIL A STRONG
COLD FRONT MOVES THROUGH THE TERMINALS LATE THIS AFTERNOON. HAVE
TRENDED PESSIMISTIC FOR BOTH VIS AND CIGS THROUGH THE AFTERNOON
THOUGH THERE WILL LIKELY BE PERIODS OF HIGHER VIS/CIGS THAT WILL
BE SHORT LIVED. AS THE COLD FRONT APPROACHES LATE THIS
AFTERNOON, MUCH COLDER AIR WILL PUSH INTO DEWPOINTS WELL INTO
THE 50S AND THERE WILL LIKELY BE A SHORT PERIOD OF DENSE FOG
UNTIL THE WESTERLY WINDS INCREASE. ADDED TEMPO MENTION FOR THIS
POTENTIAL AND TRENDS WILL NEED TO BE MONITORED. ONCE THE COLD
FRONT PASSES, VISIBILITIES SHOULD QUICKLY IMPROVE WITH CIGS
LIFTING THROUGH IFR AND INTO LOW MVFR THIS EVENING.
EARLIER THUNDERSTORM ACTIVITY HAS SHIFTED SOUTHEAST OF THE
TERMINALS AND NEW THUNDERSTORM DEVELOPMENT IS EXPECTED IN THE
NEXT FEW HOURS, ALONG A PNT/JOT/GYY LINE, WHICH WILL THEN RACE
EAST AWAY FROM THE TERMINALS. MAINTAINED TEMPO THUNDER MENTION
AT MDW/GYY BUT DROPPED TO PROB MENTION FOR ORD/DPA AND ADJUSTED
THE TIMING SLIGHTLY.
AS THE COLDER AIR SPREADS IN THIS EVENING, THERE WILL BE A
CHANCE OF FLURRIES AND THEN A PERIOD OF LIGHT SNOW IS EXPECTED
OVERNIGHT INTO EARLY MONDAY MORNING. THE COMBINATION OF THE
STRONG WINDS AND FALLING SNOW WILL LIKELY LEAD TO IFR VIS AS
WELL AS BLOWING SNOW. THIS SNOW WILL TAPER OFF TO FLURRIES AFTER
SUNRISE MONDAY MORNING AND THEN END MIDDAY.
WIND DIRECTIONS WILL ALSO BE CHALLENGING THIS AFTERNOON. IT
APPEARS A SOUTHEAST WIND WILL SLOWLY TURN NORTHERLY THEN
NORTHWESTERLY FOR THE CHICAGO TERMINALS AHEAD OF THE COLD FRONT,
THEN SHIFT WESTERLY WITH SPEEDS/GUSTS RAPIDLY INCREASING. GUSTS
INTO THE 40KT RANGE ARE EXPECTED THROUGH DAYBREAK WHEN
DIRECTIONS WILL TURN MORE NORTHWESTERLY AND SPEEDS/GUSTS WILL
BEGIN TO SLOWLY DIMINISH, LIKELY TO 30KTS BY MIDDAY MONDAY. CMS
MARINE
ISSUED AT 240 PM CST SUN DEC 28 2025
- GALE WARNING IN EFFECT FROM 5 PM SUNDAY TO 6 PM MONDAY FROM
WINTHROP HARBOR IL TO GARY IN.
- STORM WARNING IN EFFECT FROM GARY IN TO MICHIGAN CITY IN, FROM
6 PM SUNDAY TO 3 PM MONDAY.
A POWERFUL COLD FRONT WILL SWEEP ACROSS THE LAKE LATE SUNDAY,
RESULTING IN A RAPID INCREASE TO GALE FORCE AND STORM FORCE
WEST-SOUTHWEST WINDS. AS LOW PRESSURE CONTINUES TO RAPIDLY
DEEPEN NEAR LAKE HURON SUNDAY NIGHT INTO EARLY MONDAY, WESTERLY
WINDS WILL FURTHER INCREASE. CONFIDENCE IN OCCURRENCE AND
DURATION OF STORM FORCE SPEEDS/GUSTS IS HIGHEST FOR THE
SOUTHEAST PORTION OF THE LAKE.
FREEZING SPRAY WILL ALSO BE POSSIBLE LATE TONIGHT AND CONTINUE
INTO MONDAY AS AIR TEMPERATURES ARE EXPECTED TO BE IN THE LOWER
20S AND POSSIBLY INTO THE TEENS.
DOOM
LOT WATCHES/WARNINGS/ADVISORIES
IL...WIND ADVISORY FROM 6 PM THIS EVENING TO 3 PM CST MONDAY FOR
ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-ILZ012-
ILZ013-ILZ019-ILZ020-ILZ021-ILZ023-ILZ032-ILZ033-ILZ039-
ILZ103-ILZ104-ILZ105-ILZ106-ILZ107-ILZ108.
IN...WIND ADVISORY FROM 6 PM CST /7 PM EST/ THIS EVENING TO 3 PM
CST /4 PM EST/ MONDAY FOR INZ001-INZ002-INZ010-INZ011-
INZ019.
LM...DENSE FOG ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR THE IL
AND IN NEARSHORE WATERS.
GALE WARNING UNTIL 6 PM CST MONDAY FOR THE IL NEARSHORE WATERS.
STORM WARNING FROM 6 PM THIS EVENING TO 3 PM CST MONDAY FOR
THE IN NEARSHORE WATERS.
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