000  
FXUS63 KIWX 121752  
AFDIWX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NORTHERN INDIANA  
1252 PM EST SUN JAN 12 2025  
   
KEY MESSAGES  
 
- LIGHT SNOW THIS AFTERNOON AND EVENING NORTH OF US 24. DUSTING  
TO 1 INCH OF SNOW EXPECTED.  
 
- VERY COLD MONDAY NIGHT THROUGH THURSDAY MORNING WITH BELOW-  
ZERO WIND CHILLS AT TIMES.  
 
- EPISODES OF LAKE EFFECT THROUGH THE WEEK AND A SLIGHT CHANCE  
(20%) OF A CLIPPER SYSTEM MIDWEEK.  
 
 
   
UPDATE  
 
ISSUED AT 1047 AM EST SUN JAN 12 2025  
 
INCREASED POPS AND SNOW AMOUNTS THROUGH THE EARLY AFTERNOON IN  
FAR NW IN AND SW MI AS A BURST OF SNOW IS TRACKING THROUGH.  
ISSUED A SPS IN THESE AREAS GIVEN UPSTREAM OBS AND REPORTS OF  
SNOW COVERED ROADS DUE TO BRIEF HEAVIER 1/4SM TO 1/2SM SNOW. A  
MID LEVEL SHORTWAVE AND MOISTURE TRANSPORT WITHIN A LOW LEVEL  
JET HAVE CREATED THIS CORRIDOR OF ORGANIZED SNOW. THIS FEATURE  
SHOULD LIFT OUT OF THE AREA BY EARLY TO MID AFTERNOON WITH  
DECREASING SNOW INTENSITY AND COVERAGE.  
 
 
   
DISCUSSION  
 
ISSUED AT 251 AM EST SUN JAN 12 2025  
 
WE'LL BE IN THE "WARM" SECTOR OF A WEAK AREA OF LOW PRESSURE  
TRACKING THROUGH THE GREAT LAKES TODAY. RADAR RETURNS ARE ONGOING  
THANKS TO SUBTLE WARM AIR ADVECTION YET MOST OF THIS IS VIRGA DUE TO  
A MIDLEVEL WEDGE OF DRY AIR. THIS IS FORECAST TO ERODE AS UPPER-  
LEVEL FORCING IMPROVES AND THE THERMAL GRADIENT ALOFT TIGHTENS. THIS  
SHOULD ALLOW FOR TIMES OF LIGHT SNOW TODAY, PRIMARILY WEST OF I-69.  
HOWEVER, MOISTURE TRANSPORT IS OVERALL PRETTY MEAGER. WATER VAPOR  
TELLS THE STORY WITH NO POLEWARD MOISTURE TRANSPORT FROM THE GULF OR  
CENTRAL PACIFIC. BECAUSE OF THIS LACK OF MOISTURE, THE LOW CONCERN  
FOR FREEZING DRIZZLE REMAINS AS INDICATED BY A FEW FORECAST  
SOUNDINGS. CONFIDENCE IS LOW IN FZDZ OCCURRING, BUT, FEELS  
PRUDENT TO LEAN ON THE PERSISTENCE FORECAST.  
 
ONE OF TWO COLD FRONT MOVES THROUGH TONIGHT AS THE LOW LIFT  
NORTHEAST INTO ONTARIO. THIS WILL ALLOW LAKE EFFECT SNOW TO DEVELOP  
AND PERSIST INTO TUESDAY. LAKE EFFECT SNOW IS PROLONGED AS THE  
SECOND OF TWO COLD FRONTS MOVES THROUGH ON TUESDAY. THIS ALSO  
BRINGS A SLIGHT CHANCE (20%) FOR LIGHT SNOW SOUTH OF US 24 AMID  
A STRENGTHENING 500-MB JET. OUTSIDE OF THE LAKE EFFECT BELT,  
MONDAY NIGHT THROUGH WEDNESDAY NIGHT WILL BE BITTERLY COLD AS  
LOWS TUMBLE INTO THE SINGLE-DIGITS. BELOW ZERO LOWS ARE POSSIBLE  
AT A FEW SITES TUESDAY NIGHT. WIND CHILLS WILL BE WELL BELOW  
ZERO.  
 
LATE WEEK FEATURES A BRIEF MODERATION IN TEMPERATURE WITH HIGHS  
CREEPING INTO THE MID-30S. THIS OCCURS AS A DEEP TROUGH ENCOMPASSES  
THE WESTERN 2/3 OF THE CONUS AND RIDGING NOSES INTO OUR AREA.  
DEPENDING ON THE DEPTH OF SAID TROUGH, A LOW IS FORECAST TO EJECT  
NORTHEAST THROUGH THE TENNESSEE RIVER VALLEY. IF IT TRACKS FAR ENOUGH  
NORTH, WE COULD FACE SOME PRECIPITATION-TYPE ISSUES. FOR NOW,  
RETAINED THE RAIN-SNOW CHANCE FOR SATURDAY. SHARPLY COLDER ONCE  
MORE AFTER NEXT WEEKEND.  
 
 
   
AVIATION /18Z TAFS THROUGH 18Z MONDAY/  
 
ISSUED AT 1243 PM EST SUN JAN 12 2025  
 
A WEAK UPPER LEVEL SYSTEM WAS BRINGING LIGHT TO OCCASIONALLY  
MODERATE SNOW TO NORTHWEST INDIANA INTO FAR SOUTHWEST LOWER  
MICHIGAN. MADE SOME UPDATES TO THE SBN TAF WITH THE INCLUSION  
OF FREEZING DRIZZLE WITH THE TOP OF THE CLOUD LAYER BECOMING  
WARMER THE -10C. PER GFS BUFKIT, INVERSION HEIGHTS FALL WITH THE  
CLOUD LAYER BECOMING MORE SHALLOW.  
 
 
   
IWX WATCHES/WARNINGS/ADVISORIES  
 
IN...NONE.  
OH...NONE.  
MI...NONE.  
MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EST WEDNESDAY FOR LMZ043-046.  
 
 
 
 
 
UPDATE...STEINWEDEL  
DISCUSSION...BROWN/STEINWEDEL  
AVIATION...SKIPPER  
CLICK HERE TO GO TO PREVIOUS BULLETINS.
The Nexlab IN Page
The Nexlab OH Page
The Nexlab MI Page
Main Text Page