776
FXUS63 KIWX 191720
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1220 PM EST MON JAN 19 2026
KEY MESSAGES
- LAKE EFFECT SNOW CONTINUES TODAY ON INTO TUESDAY. THE HEAVIEST
FALLS THIS MORNING AND CONTINUES TO WEAKEN THROUGH THE PERIOD.
ADDITIONAL SNOW AMOUNTS TOTAL 2 TO 4 INCHES ACROSS THE
ADVISORY LOCATIONS IN MI, WHEREAS LESS THAN 2 INCHES
ADDITIONAL SNOW IS FORECAST FOR THE INDIANA COUNTIES IN THE
ADVISORY.
- DANGEROUS WIND CHILLS AROUND 15 BELOW ZERO EXPECTED LATE TODAY
THROUGH EARLY TUESDAY.
- ANOTHER FAST MOVING SYSTEM WILL BRING SOME LIGHT SNOW
ACCUMULATIONS TUESDAY NIGHT INTO EARLY WEDNESDAY, ESPECIALLY
ALONG AND NORTH OF THE TOLL ROAD. STILL, ANOTHER SYSTEM
PROVIDES SNOW AND LAKE EFFECT SNOW FOR WEDNESDAY NIGHT AND
THURSDAY.
- TEMPERATURES MODERATE BACK INTO THE LOWER 30S BRIEFLY
WEDNESDAY, BUT TEMPERATURES TURN COLDER ONCE AGAIN FOR LATTER
PORTIONS OF WORK WEEK INTO NEXT WEEKEND.
UPDATE
ISSUED AT 1040 AM EST MON JAN 19 2026
A VIGOROUS SNOW BAND ASSOCIATED WITH POST-FRONTAL ARCTIC
BOUNDARY HAS TRANSITIONED MORE INTO A LAKE EFFECT SNOW SETUP
THIS MORNING. A LOW LEVEL BAROCLINIC ZONE APPEARS TO HAVE BEEN
SHARPENED DUE TO SOUTHERN GREAT LAKES THERMAL MODIFICATION TO
PRODUCE A NARROW BAND OF LOW LEVEL FGEN THAT AIDED IN A STRONG
SNOW BAND THAT PUSHED ACROSS PORTIONS OF NORTH CENTRAL/NORTHEAST
INDIANA. THIS BAND ALSO WAS CO-LOCATED AT THE LEADING EDGE OF A
STRONG 500 MB VORTICITY ADVECTION. THE LOW LEVEL FGEN FORCING
HAS WEAKENED WITH EASTWARD EXTENT WHICH HAS ALLOWED THIS
SYNOPTICALLY FORCED BAND TO TRANSITION TO MORE OF A PURE LAKE
EFFECT SETUP. EVEN AREAS WHICH EXPERIENCED VERY LIGHT SNOW
ACCUMULATIONS OF AN INCH OR LESS, POST-FRONTAL WIND GUSTS TO 30
TO 35 MPH WILL RESULT IN PATCHY/AREAS OF BLOWING SNOW INTO THIS
AFTERNOON. THE STRONGEST WINDS HAVE BEEN NOTED BRIEFLY ALONG
STRONGEST ISALLOBARIC GRADIENT WITH THE ARCTIC FRONT (40-45
MPH), BUT THESE MAGNITUDES ARE BEGINNING TO DEPART NW OHIO.
LAKE EFFECT SNOW SHOWERS WILL CONTINUE IN WESTERLY FETCH REGIME
THROUGH THE AFTERNOON, ALTHOUGH SNOW ACCUMULATION EFFICIENCY MAY
STRUGGLE SOMEWHAT AS THERMAL PROFILES FALL OUT OF THE OPTIMAL
DGZ REGION DUE TO THE STRENGTH OF CAA. MULTIBAND SETUP SHOULD
PRODUCE VARIABLE ACCUMULATIONS OF 1 TO 3 INCHES (LOCALLY 4?) OF
ADDITIONAL ACCUMULATIONS NORTH OF I-80 INTO THIS AFTERNOON. DID
EXTEND THE WINTER WEATHER ADVISORY INTO BRANCH AND HILLSDALE
BASED ON SOME OBSERVATIONAL IMPACTS FROM EVEN LIGHT SNOW AMOUNTS
THIS MORNING.
GIVEN SLIGHTLY STRONGER WINDS THAN EXPECTED, DID GO AHEAD AND
MOVE UP ALL OF THE COLD WEATHER ADVISORIES TO BE VALID AT
CURRENT TIME, WITH NO CHANGE TO ENDING TIME (14Z TUESDAY AM).
DISCUSSION
ISSUED AT 308 AM EST MON JAN 19 2026
COLD AIR ADVECTION WAS ENTERING THE AREA THIS MORNING BEHIND THE
ARCTIC FRONT AND THIS SETS UP TWO HAZARDS FOR MONDAY.
THE FIRST OF WHICH IS THE SNOW. LAKE EFFECT SNOW IS UNDERWAY ACROSS
THE AREA AS SOUTHWEST WINDS VEER MORE WEST NORTHWESTERLY TODAY.
FAVORABLE TRAJECTORIES, AMPLE THETA-E INSTABILITY, AND LOW LEVEL
MOISTURE ALL MAKE THE ATMOSPHERE CONDUCIVE TO LAKE EFFECT SNOW.
INITIAL LAKE INDUCED INVERSION UP BETWEEN 7500 AND 8500 FT FALL
SLOWLY DURING THE DAY TODAY INDICATING THE INTENSITY OF LAKE EFFECT
SNOW IS EXPECTED TO SLOWLY SLACKEN THROUGH THE PERIOD, WHICH IS ALSO
EVIDENT BY THE GENERAL TENDENCY TO LOSE LOW LEVEL MOISTURE. ANOTHER
NEGATIVE FOR THIS IS THAT WHILE WE HAVE GOOD OMEGA CROSS HAIRS WITH
THE DGZ, THE MOISTURE IS ACTUALLY MUCH HIGHER IN THE ATMOSPHERE
MEANING WE'RE GETTING MORE PLATES THAN DENDRITES LOWERING THE SLR A
LITTLE. STILL, GIVEN THE COLD AIR, THE DRY SNOW AND GUSTY WINDS,
INITIALLY GUSTING 30 TO 35 MPH THAT DO RELAX A LITTLE TO MORE LIKE
25 TO 30 MPH BY DAY'S END, ALLOW FOR HAZARDOUS DRIVING DUE TO
LOWERED VISIBILITY FROM BLOWING SNOW, BUT ALSO FROM DRIFTING SNOW,
ESPECIALLY ON N-S ROADS. AS A STRONG SHORTWAVE CROSSES LAKE MI THIS
MORNING IT LOOKS TO TURN THOSE TRAJECTORIES MORE WESTERLY AND
INCREASE SNOW RATES UNTIL AROUND 12 OR 13Z WHEN THE SURFACE TROUGH
PUSHES EASTWARD AWAY FROM THE LAKE INFLUENCE. LIGHT LAKE EFFECT SNOW
IS EXPECTED TO CONTINUE THIS AFTERNOON INTO EARLY TUESDAY.
THE OTHER HAZARD IS THE VERY COLD AIR. A COLD WEATHER ADVISORY
HAS BEEN ISSUED FOR WIND CHILLS THAT DIP DOWN TO -15F. IT IS A
DELAYED ARRIVAL FROM WHAT ONE WOULD NORMALLY EXPECT, WHICH IS TO
GET THE DEEPEST COLD IN THE EARLY MORNING AND THEN HAVE
TEMPERATURES INCREASE DURING THE DAY DIURNALLY. THIS TIME, WE
ACTUALLY THE COLDEST WIND CHILLS MID MORNING BEFORE THE WINDS
SLOWLY RELAX, BUT THE TEMPERATURES STAY IN THE MID TO UPPER
SINGLE DIGITS AND LOW TEENS THROUGH THE DAY TODAY. GIVEN THE 850
MB STAY IN THE -20S CELSIUS TODAY AND TONIGHT, WE HAVE THE COLD
WEATHER ADVISORY LASTING INTO TUESDAY MORNING. TEMPERATURES ARE
SECURELY INTO THE MID TO POTENTIALLY LOWER SINGLE DIGITS AWAY
FROM THE LAKE CLOUD BLANKET, BUT THE WINDS ARE 10 TO 20 MPH
WEAKER TUESDAY AM. HIGH PRESSURE PASSING BY TO OUR SOUTH TUESDAY
MORNING ALLOWS WAA TO BEGIN TO WORK INTO THE AREA SO, WHILE
TODAY'S HIGHS STRUGGLE TO GET OUT OF THE TEENS, LOW 20F DEGREE
TEMPERATURES BEGIN TO POKE INTO OUR SOUTHWEST TUESDAY AFTERNOON.
MID LEVEL RIDGING AND THE WAA'S SOUTHWEST TRAJECTORIES SPELL AN END
TO THE LAKE EFFECT SNOW TUESDAY AFTERNOON. HOWEVER, A CLIPPER SYSTEM
IS HOT ON THE WANING PRECIPITATION'S HEELS FOR WEDNESDAY. A THETA-E
PLUME AND GULF CONNECTION IS NOTABLE IN MODELS WITH THIS SYSTEM AS
IT PASSES BY JUST TO THE NORTH OF THE AREA MEANING IT WILL HAVE TO
BE INTERROGATED FOR SOME SNOW ACCUMULATIONS AS IT PASSES BY. IT WILL
ALSO HAVE A LAKE ENHANCEMENT RESPONSE ON ITS BACK SIDE ALTHOUGH IT
DOES APPEAR THAT THE NAM BEH BUFKIT SOUNDINGS INDICATE MUCH WEAKER
LAKE INDUCED INSTABILITY AND DRY AIR IN THE LOWEST LEVELS.
BETTER OMEGA CROSS HAIRS WITH OVERLAID MOISTURE OCCURS FOR A
BRIEF PERIOD WEDNESDAY NIGHT AS ANOTHER CLIPPER MOVES THROUGH
THE AREA, BUT THERE IS ALSO INDICATIONS OF RIMING ON THE FLAKES
WITH THE OMEGA CENTER AT OR JUST BELOW THE DGZ. THIS SYSTEM HAS
A HIGHER DEW POINT PLUME, BUT DOES APPEAR TO HAVE A WEAKER
CONNECTION TO THE GULF THIS TIME AROUND, WHICH WOULD INDICATE
WEAKER ACCUMULATIONS THAN THE WEDNESDAY SYSTEM. THE CLIPPER
SYSTEM IS OUT OF THE AREA BY THURSDAY MORNING AND THERE WILL BE
A LAKE RESPONSE ON ITS BACK SIDE.
IT LOOKS LIKE STILL ANOTHER CLIPPER SYSTEM ARRIVES THURSDAY NIGHT,
BUT THAT LOOKS MUCH DRIER AND NOT WITH MUCH GULF CONNECTION. THERE'S
ALSO A LAKE RESPONSE BEHIND IT AGAIN.
THE COLD THAT FOLLOWS THIS CLIPPER SYSTEM FOR FRIDAY MORNING IS
QUITE DEEP WITH THE -25C CONTOUR PASSING THROUGH THE AREA AND THE
NEGATIVE 30C CONTOUR IN PLAY. FURTHER EVIDENCE TO THE STRONG
COLD AIR IS THE ANOMALOUS 1050 MB HIGH PRESSURE SYSTEM THAT
PASSES THROUGH THE AREA SATURDAY/SATURDAY NIGHT.
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 1214 PM EST MON JAN 19 2026
IN THE WAKE OF AN ARCTIC FRONTAL PASSAGE THIS MORNING, GUSTY
WEST WINDS, BLOWING SNOW, AND ONGOING SCATTERED LAKE EFFECT ARE
MAKING FOR AN ACTIVE START TO THE WEEK. WINDS HAVE BEEN
SUSTAINED AROUND 20 KTS WITH GUSTS AS HIGH AS 30 KTS; WINDS WILL
GRADUALLY START TO RELAX THIS EVENING, BUT GUSTS TO 20 KTS WILL
STILL BE POSSIBLE OVERNIGHT, ESPECIALLY NEAR LAKE MICHIGAN. AS
SCATTERED LAKE EFFECT SNOW SHOWERS CONTINUE NEAR AND NORTH OF
I-80/I-90, THE GUSTY WEST WINDS ARE ALSO LEADING TO AREAS OF
BLOWING SNOW AND SIGNIFICANTLY REDUCED VISIBILITY. UNTIL WINDS
START TO DIMINISH THIS EVENING, EXPECT THE BLOWING SNOW AND
REDUCED VISIBILITIES TO PERSIST. VISIBILITIES ARE GENERALLY MVFR
AWAY FROM THE LAKE AND IFR TO POTENTIALLY EVEN LIFR CLOSER TO
THE LAKE (WHERE WINDS ARE STRONGER AND MORE SNOW IS ON THE
GROUND TO BLOW AROUND). KSBN CONTINUES TO SEE 1/4 MILE
VISIBILITY AS OF MIDDAY, WHILE KFWA HAS AVERAGED ABOUT 3 MILES.
LAKE EFFECT TAPERS OFF THIS EVENING AND SKIES WILL CLEAR OUT
OVERNIGHT AWAY FROM THE LAKE. EXPECT WINDS TO CONTINUE FROM THE
WEST TOMORROW, ALTHOUGH NOT AS STRONG AS TODAY.
IWX WATCHES/WARNINGS/ADVISORIES
IN...WINTER WEATHER ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
FOR INZ005-103-104-204.
COLD WEATHER ADVISORY UNTIL 9 AM EST /8 AM CST/ TUESDAY FOR
INZ005>009-012>015-017-018-020-022>027-032>034-103-104-
116-203-204-216.
OH...COLD WEATHER ADVISORY UNTIL 9 AM EST TUESDAY FOR OHZ001-002-
004-005-015-016-024-025.
MI...COLD WEATHER ADVISORY UNTIL 9 AM EST TUESDAY FOR MIZ080-081.
WINTER WEATHER ADVISORY UNTIL 1 AM EST TUESDAY FOR MIZ078>081-
177-277.
MARINE...GALE WARNING UNTIL 4 PM EST THIS AFTERNOON FOR LMZ043-046.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST TUESDAY FOR LMZ043-
046.
UPDATE...MARSILI
DISCUSSION...ROLLER
AVIATION...JOHNSON
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page