851
FXUS63 KIWX 200807
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
307 AM EST TUE JAN 20 2026
KEY MESSAGES
- COLD WIND CHILLS OF 10 TO 20 BELOW ZERO WARM THIS MORNING. OUR
NEXT CHANCE FOR COLD WIND CHILLS OF 10 TO 20 BELOW ZERO IS
FRIDAY.
- LAKE EFFECT SNOW SHOWERS LINGER THIS MORNING NORTH OF THE TOLL
ROAD. WINDS RELAX THIS MORNING TO 20 TO 25 MPH, BUT BLOWING
AND DRIFTING OF SNOW IS STILL POSSIBLE ON NORTH-SOUTH ROADS.
- ANOTHER SYSTEM WILL BRING LIGHT SNOW ACCUMULATIONS LATE
TUESDAY NIGHT INTO WEDNESDAY MORNING. 3 TO 6 INCHES OF SNOW
ACCUMULATION ARE POSSIBLE IN BERRIEN, CASS, AND ST JOSEPH
COUNTIES, MICHIGAN.
- TEMPERATURES WARM BRIEFLY INTO LOW TO MID 30S FOR WEDNESDAY
BUT AN ARCTIC AIRMASS AND MUCH BELOW NORMAL TEMPERATURES
RETURN FOR LATER WORK WEEK INTO THE WEEKEND.
- THERE ARE ADDITIONAL PERIODIC CHANCES OF LAKE EFFECT SNOW
SHOWERS WEDNESDAY NIGHT THROUGH THE WEEKEND.
DISCUSSION
ISSUED AT 248 AM EST TUE JAN 20 2026
COLD AIR TO THE TUNE OF -20C AT 850 MB STILL REMAINS ACROSS THE AREA
THIS MORNING. WHILE THE MAIN JET MAX HAS ALREADY PUSHED EAST, 25 TO
35 KTS STILL RESIDES UP AT 850 MB ALLOWING FOR A 20 TO 25 MPH
GUST. THESE TEMPS AND BREEZY WINDS, AT TIMES, WILL ALLOW FOR
STILL COLD WIND CHILLS THIS MORNING IN THE NEGATIVE LOW TO MID
TEENS. BE SURE TO BUNDLE UP IF OUTSIDE TODAY.
LAKE EFFECT SNOW CONTINUES WITH NEGATIVE THETA-E LAPSE RATES STILL
HOLDING STRONG INTO THIS MORNING UNTIL SOUTHERLY WIND
TRAJECTORIES FINALLY MAKE THEIR PRESENCE FELT IN THE AREA AND
PUSH THE SHEARED OUT AREA OF VORTICITY NORTH OF THE AREA. THIS
WARM AIR ADVECTION COMES IN IN EARNEST THIS AFTERNOON ALLOWING
AREAS SOUTHWEST OF US-30 TO ACHIEVE UPPER TEENS AND LOW 20S FOR
HIGHS BEFORE SUNSET.
HEIGHT RISES AND MID LEVEL RIDGING ALLOW FOR SUPPRESSION OF
WIDESPREAD PRECIPITATION EVEN FOR THE LAKE BELT FROM LATER TODAY
INTO TONIGHT. HOWEVER, A CLIPPER SYSTEM ALREADY INTRODUCES SNOW
CHANCES TO THE AREA LATER TUESDAY NIGHT AND THAT CONTINUES
WEDNESDAY. THIS IS WHEN THE BETTER MOISTURE PLUME ARRIVES, AND
THIS ONE HAS A CONNECTION TO THE GULF. AS SUCH, IT LOOKS LIKE 3
TO 6 INCHES OF SNOW IS MOST POSSIBLE NORTH OF THE TOLL ROAD LATE
TUESDAY NIGHT INTO WEDNESDAY. ENERGETIC LAPSE RATES AND A
DEPARTING LOW PRESSURE SYSTEM ALLOW FOR A CHANCE FOR GUSTY WINDS
30 TO 40 MPH ESPECIALLY IN THE I-69 CORRIDOR IN THE MORNING.
WHAT MAY BE A BRIEF BREAK IN THE WEATHER WEDNESDAY AFTERNOON
AND EVENING QUICKLY REVERTS BACK TO PRECIPITATION AS A LITTLE
DRIER CLIPPER PUSHES THROUGH WEDNESDAY NIGHT. THIS ONE SHOWS
SIGNS OF A MOISTURE PLUME, BUT IT DOESN'T APPEAR TO HAVE A GULF
CONNECTION LIKE THE PREVIOUS ONE DOES. THE NAM APPEARS TO HAVE
SOME SBCAPE AND EXCITED SNOW SQUALL PARAMETER INCLUDING SOME
ENERGETIC LOW LEVEL LAPSE RATES THAT CONTINUE INTO THE OVERNIGHT
HOURS.
THE SHEARED AREA OF VORTICITY BEHIND THE AFOREMENTIONED CLIPPER
SYSTEM REMAINS NEAR THE TEAR DROP OF LAKE MI WITH TIMES OF CAA
THROUGH THE AREA ALLOWING FOR TIMES OF LAKE ENHANCEMENT BETWEEN
WEDNESDAY EVENING AND THURSDAY EVENING. ON THE WHOLE, THESE CHANCES
LOOK TO BE WEAK AND LIGHT, BUT THE THE THURSDAY NIGHT AND
FRIDAY LAKE ENHANCED PROFILES APPEAR MORE RESPECTABLE.
FOR THURSDAY NIGHT, A VORT MAX ROUNDS THE BASE OF THE TROUGH AND
PUSHES ANOTHER DRY CLIPPER SYSTEM THROUGH THE AREA. THIS LOOKS TO
AFFECT TRAJECTORIES ACROSS LAKE MI AND LIKELY KEEPS THE LAKE
ENHANCEMENT GOING INTO THE WEEKEND. THE OTHER STORY IS THE MUCH
COLDER AIR ARRIVING FRIDAY MORNING WITH -25 TO -30C 850 MB
TEMPS MOVING ACROSS THE AREA. THE GOOD THING THIS TIME IS THAT
WITH THE ARRIVAL OF THE STRONG 1050 MB HIGH PRESSURE SYSTEM, THE
AIR WILL BE COLD, BUT THE WINDS WILL BE MORE RELAXED THAN OUR
RECENT COLD AIRMASS DEPARTING. HIGHS FRIDAY AND SATURDAY
STRUGGLE TO GET INTO THE TEENS AND LOWS FRIDAY NIGHT THROUGH
SUNDAY NIGHT ARE IN THE SINGLE DIGITS ABOVE AND BELOW ZERO. THIS
WOULD MAKE COLD WIND ADVISORY THRESHOLD WIND CHILLS POSSIBLE
AGAIN OVERNIGHT.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 1220 AM EST TUE JAN 20 2026
LAKE EFFECT SNOW/STRATUS WILL CONTINUE AT KSBN THROUGH THE
EARLY MORNING BUT CONDITIONS WILL STEADILY IMPROVE AS INVERSION
HEIGHTS LOWER, WINDS BACK SLIGHTLY, AND DRY AIR ADVECTION
INCREASES. CONFIDENCE IN THE EXACT TIMING OF THE TRANSITION TO
VFR IS LOW BUT SHOULD OCCUR NO LATER THAN 13Z. VFR THEN EXPECTED
FOR THE REST OF THE PERIOD GIVEN SHORTWAVE RIDGING. THE NEXT
TROUGH MOVES INTO THE GREAT LAKES EARLY WED MORNING AND MAY
BRING SOME MORE LIGHT SNOW/MVFR CEILINGS TO KSBN BUT THAT
APPEARS TO BE JUST OUTSIDE THIS FORECAST WINDOW.
IWX WATCHES/WARNINGS/ADVISORIES
IN...COLD WEATHER ADVISORY UNTIL 9 AM EST /8 AM CST/ THIS MORNING
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 THIS MORNING FOR OHZ001-
002-004-005-015-016-024-025.
MI...COLD WEATHER ADVISORY UNTIL 9 AM EST THIS MORNING FOR MIZ080-
081.
WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ078-
177-277.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LMZ043-
046.
HEAVY FREEZING SPRAY WARNING UNTIL 10 AM EST THIS MORNING FOR
LMZ043-046.
DISCUSSION...ROLLER
AVIATION...AGD
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