046
FXUS63 KIWX 082307
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
607 PM EST SAT NOV 8 2025
KEY MESSAGES
- RAIN OVERSPREADS THE AREA TONIGHT AND CHANGES OVER TO WET SNOW BY
EARLY SUNDAY MORNING. 1-2" IS POSSIBLE ON GRASSY/ELEVATED SURFACES,
ALTHOUGH TRAVEL IMPACTS ARE NOT EXPECTED.
- HEAVY LAKE EFFECT SNOW IS POSSIBLE NEAR LAKE MICHIGAN SUNDAY NIGHT
THROUGHOUT THE DAY ON MONDAY.
- 6-12" OF SNOW IS LIKELY (WITH LOCALLY HIGHER AMOUNTS POSSIBLE) IN
LA PORTE, ST JOSEPH [IN], AND BERRIEN COUNTIES BY MONDAY EVENING.
TRAVEL IMPACTS ARE POSSIBLE FOR BOTH THE MONDAY MORNING AND EVENING
COMMUTES.
- NEAR RECORD COLD HIGH TEMPERATURES POSSIBLE MONDAY. BREEZY
NORTHWEST WINDS WILL MAKE FOR WIND CHILLS ONLY IN THE TEENS
AND 20S.
DISCUSSION
ISSUED AT 242 PM EST SAT NOV 8 2025
A VERY ACTIVE WEATHER PATTERN COMMENCES TONIGHT THROUGH MONDAY WITH
THE FIRST SNOW OF THE SEASON EXPECTED ACROSS MUCH OF THE FORECAST
AREA, INCLUDING A SIGNIFICANT LAKE EFFECT SNOW SETUP SUNDAY EVENING
INTO MONDAY. A SURFACE LOW PRESSURE SYSTEM CURRENTLY CENTERED OVER
SOUTH DAKOTA WILL MOVE SOUTHEAST TONIGHT OVER THE OHIO RIVER VALLEY.
THE CENTER OF THE LOW IS EXPECTED TO BE OVER CENTRAL OR SOUTHERN
INDIANA BY TONIGHT (MOST HI RES MODELS HAVE SHIFTED SOUTH TO FAVOR
SOUTHERN INDIANA). RAIN OVERSPREADS THE AREA AFTER 00Z SUNDAY,
CHANGING OVER TO WET SNOW AS EARLY AS 06Z-09Z FROM NORTH TO SOUTH AS
TEMPERATURES HOVER RIGHT AROUND FREEZING. NORTH OF THE CENTER OF THE
LOW, 925-850 MB FRONTOGENESIS INCREASES OVERNIGHT ALONG AND
NORTH OF THE US 30 CORRIDOR AS THE LOW DEEPENS. A QUICK 1-2" OF
SYNOPTIC (SYSTEM) SNOW IS POSSIBLE ON GRASSY/ELEVATED SURFACES,
ESPECIALLY IN AREAS WHERE HEAVY SNOW RATES CAN OVERCOME THE
ABOVE-FREEZING SURFACE TEMPERATURES. MINIMAL, IF ANY, TRAVEL
IMPACTS DUE TO ROAD/PAVEMENT TEMPERATURES BEING ABOVE FREEZING.
AS THE LOW EXITS EASTWARD INTO THE OHIO RIVER VALLEY, BREEZY NORTH
WINDS ON THE BACKSIDE OF THE LOW WILL ALLOW FOR LAKE EFFECT SNOW TO
DEVELOP AS EARLY AS 12Z-15Z. A SINGLE, DOMINANT, N-S ORIENTED LAKE
EFFECT SNOW BAND IS EXPECTED TO DEVELOP ACROSS LAKE MICHIGAN DUE TO
THE ELONGATED NORTHERLY FETCH EXTENDING ALL THE WAY UP TO LAKE
SUPERIOR. THE LAKE EFFECT SNOW BAND SHOULD INITIALLY START OFF
OVER FAR NW INDIANA (NEAR GARY AND CHESTERTON, IN) BEFORE
PIVOTING UP INTO MICHIGAN CITY, IN AND EVEN UP TO ST JOSEPH, MI
AS LOW LEVEL CONVERGING WINDS TAKE ON A MORE NORTH-NORTHWEST
COMPONENT. DURING THE DAY SUNDAY, LAKE EFFECT SNOW IS EXPECTED
TO PERSIST ACROSS THE TYPICAL LAKE EFFECT SNOWBELTS IN NW
INDIANA AND FAR SW LOWER MICHIGAN. WITH DAYTIME HIGHS IN THE
UPPER 30S TO NEAR 40 DEGREES, ACCUMULATIONS WILL LIKELY BE
LIMITED. DEPENDING ON HOW FAR INLAND THE LAKE EFFECT SNOW BAND
GETS, SNOW IS POSSIBLE AS FAR EAST AS IN- 15 AND AS FAR SOUTH AS
THE US 24 CORRIDOR. CAN'T RULE OUT 1-2" OF SNOW ON
GRASSY/ELEVATED SURFACES BUT IMPACTS DURING THE DAY SHOULD BE
LIMITED. VISIBILITIES WILL LIKELY BE LOW WITHIN THE BAND AND IF
ANY HEAVIER SNOW RATES DO MATERIALIZE, THERE COULD BE SOME MINOR
ACCUMULATIONS ON ROADS, ESPECIALLY WITHIN THE SNOWBELTS.
LAKE EFFECT SNOW CONTINUES LATE SUNDAY OVERNIGHT INTO MONDAY MORNING
AND THE ENVIRONMENT WILL BECOME INCREDIBLY FAVORABLE. SURFACE LOW
TEMPERATURES SUNDAY NIGHT WILL BE IN THE 20S, WHICH WILL LIMIT
MELTING. MODELS VARY WIDELY ON THE POSITIONING OF THE LAKE EFFECT
SNOW BAND SUNDAY NIGHT AND INTO EARLY MONDAY DUE TO THE DEVELOPMENT
OF A MESOLOW. HOW LONG THE BAND STAYS OVER ONE AREA IS HIGHLY
UNCERTAIN. A MESOLOW WILL LIKELY FORM OVER LAKE MICHIGAN AND DROP
DUE SOUTH OVER THE LAKE, WHICH WILL PULL THE AXIS OF THE LAKE EFFECT
SNOW TO THE WEST OVER THE CHICAGO METRO AND POTENTIALLY EVEN AS FAR
WEST AS WAUKEGAN, IL AROUND 06Z-09Z MONDAY. FOR LOCATIONS BETWEEN
MICHIGAN CITY TO ST JOSEPH, MI, THERE WILL LIKELY BE A LULL IN SNOW
FROM THIS TIMEFRAME UNTIL ABOUT 12Z-15Z MONDAY WHEN THE LAKE EFFECT
SNOW BAND PIVOTS BACK OVER OUR FORECAST AREA. INCREASING INVERSION
HEIGHTS TO AROUND 15,000 FT AND IMPRESSIVELY STEEP LOW LEVEL LAPSE
RATES OF 8.5-9 C/KM WILL CREATE A PHENOMENAL THERMODYNAMIC SETUP,
AND WITH A LAKE SUPERIOR TO LAKE MICHIGAN CONNECTION, THE BAND WILL
BE CAPABLE OF PRODUCING SNOWFALL RATES OF UP TO 2-3"/HOUR WITH
THUNDERSNOW POSSIBLE (ESPECIALLY OVER NW INDIANA). DEPENDING ON WHEN
AND WHERE THE LAKE EFFECT SNOW BAND SETS UP, THERE MAY BE IMPACTS TO
THE MONDAY MORNING AND EVENING COMMUTES, ESPECIALLY ALONG THE I-94
AND I-80/I-90 CORRIDORS. BE PREPARED FOR SLICK, SNOW COVERED ROADS!
NEGATIVE THETA-E LAPSE RATES MAY ALLOW FOR THE BAND TO EXTEND
FURTHER INLAND DURING THE DAY MONDAY (LIKELY SIMILAR TO SUNDAY IN
THAT THE EASTERN EXTENT WILL BE IN-15 AND THE SOUTHERN EXTENT WILL
BE US 24). IF THIS HAPPENS, TRAVEL IMPACTS MAY ALSO OCCUR ON PARTS
OF US 30 IN NORTH CENTRAL AND NW INDIANA.
FEW CHANGES HAVE BEEN MADE TO HEADLINES AND FORECAST SNOW AMOUNTS
DUE TO THE LINGERING UNCERTAINTY. CASS COUNTY, MI HAS BEEN ADDED TO
THE WINTER STORM WATCH, WHICH WILL BE IN EFFECT FROM 1 PM EST SUNDAY
TO 7 PM EST MONDAY. IF THE LAKE EFFECT SNOW BAND STAYS OVER OUR AREA
FOR LONGER SUNDAY NIGHT INTO MONDAY MORNING, SNOWFALL AMOUNTS COULD
BE HIGHLY VARIABLE AT A COUNTY LEVEL DUE TO THE UNPREDICTABILITY
OF MESOVORTICES WITHIN THE BAND. CURRENT FORECAST SNOW AMOUNTS
BETWEEN SUNDAY AFTERNOON THROUGH MONDAY EVENING ARE 6-12" IN LA
PORTE, BERRIEN, AND ST JOSEPH [IN] COUNTIES, ALTHOUGH I WOULD
NOT BE SURPRISED IF LOCALLY HIGHER AMOUNTS OF 1.5 TO 2 FEET ARE
REALIZED SOMEWHERE NEAR SOUTHERN LAKE MICHIGAN. SOME BLOWING AND
DRIFTING MAY OCCUR IN AREAS THAT SEE THE HIGHEST SNOW AMOUNTS.
BREEZY NORTHWEST WINDS AND STRONG CAA WILL KEEP TEMPERATURES AROUND
20 DEGREES BELOW NORMAL FOR THIS TIME OF YEAR ON MONDAY. HIGH
TEMPERATURES WILL BE IN THE LOW TO MID 30S, WITH SOME LOCATIONS
STRUGGLING TO GET ABOVE FREEZING. WHEN FACTORING IN THE WINDS, WIND
CHILLS WILL ONLY BE IN THE TEENS AND 20S ALL DAY MONDAY. WINDS SHIFT
TO THE WEST BY MONDAY EVENING, CUTTING OFF ANY REMAINING LAKE EFFECT
SNOW.
THROUGH THE REST OF THE WEEK, TEMPERATURES GRADUALLY WARM AND RETURN
TO NEAR NORMAL BY FRIDAY AND SATURDAY. A COLD FRONT BRINGS SLIGHT
CHANCES FOR LAKE EFFECT RAIN AND SNOW SHOWERS WEDNESDAY, BUT QUIET
AND DRY WEATHER RESUMES THURSDAY THROUGH THE WEEKEND.
AVIATION /00Z TAFS THROUGH 00Z MONDAY/
ISSUED AT 552 PM EST SAT NOV 8 2025
SHORT WAVE WILL CONTINUE TO MOVE INTO THE AREA TONIGHT AND WILL
PROVIDE DECENT LIFTING IN THE LOW AND MID LEVELS WHICH IS SEEN
ON THE LATEST RADAR TRENDS WITH RAIN SHOWERS AND DRIZZLE MOVING
INTO THE WESTERN PORTIONS OF THE AREA. THE EXPECTATION IS THAT
WITH THE INCREASE IN COLD AIR ADVECTION WILL BRING A CHANGEOVER
TO A MIX OF RAIN SHOWERS AND WET SNOW OVERNIGHT ESPECIALLY FOR
KSBN BUT WILL EVENTUALLY PUSH EASTWARD INTO THE KFWA SITE. WITH
THE WET NATURE OF THE SNOW COUPLED WITH WARMER GROUND
TEMPERATURES MOST OF THE FALLING SNOW WILL MELT ON CONTACT. EAST
WINDS WILL ALSO BE ON THE INCREASE WITH BETTER GRADIENTS AS THE
MAIN LOW CIRCULATION ARRIVES. BACKING OF THE WINDS TO MORE
NORTHWEST ON SUNDAY AS THE SYSTEM PUSHES EASTWARD. CONDITIONS
WILL DROP TO IFR OR LIFR TONIGHT WITH LOWERED CIGS AND VSBYS IN
PRECIPITATION AND PERHAPS SOME IMPROVEMENT TO LOWER END MVFR
SUNDAY MORNING AS WINDS BACK TO THE NORTHWEST. SUNDAY AFTERNOON
AND EVENING MUCH COLDER AIRMASS WILL INCREASE LAKE EFFECT
SNOW AND SHOWERS WHICH WILL MAINLY AFFECT KSBN BEING IN CLOSER
PROXIMITY TO THE LAKE BUT SOME SNOW SHOWERS WOULD NOT BE OUT OF
THE QUESTION TO MAKE IT FURTHER SOUTHEAST TO KFWA BUT LESS
LIKELY. UNFORTUNATELY, WITH THE MESOSCALE NATURE OF THE LAKE
EFFECT, WHEREVER THE BAND ANCHORS WILL DETERMINE WHERE THE
HEAVIEST PRECIPITATION WILL SET UP BUT ALSO ANY MEANDERING OF
THE BANDS AND THE FURTHER BACKING OF THE WINDS COULD CHANGE
QUICKLY THE INTENSITY AND LOCATION OF THE SNOWFALL.
IWX WATCHES/WARNINGS/ADVISORIES
IN...WINTER STORM WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY
EVENING FOR INZ012-014-103-104-203-204.
OH...NONE.
MI...WINTER STORM WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY
EVENING FOR MIZ078-177-277.
MARINE...SMALL CRAFT ADVISORY FROM 3 AM SUNDAY TO 7 PM EST MONDAY FOR
LMZ043-046.
DISCUSSION...JOHNSON
AVIATION...ANDERSEN
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