465  
FXUS63 KIWX 051813  
AFDIWX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NORTHERN INDIANA  
113 PM EST MON JAN 5 2026  
   
KEY MESSAGES  
 
- TRENDING WARMER THIS WEEK WITH HIGHS POTENTIALLY INTO THE 50S BY  
THURSDAY AND FRIDAY.  
 
- AREAS OF FOG AND DRIZZLE TUESDAY INTO TUESDAY NIGHT.  
 
- PERIODS OF RAIN (70-90%) LATE THURSDAY INTO THURSDAY NIGHT.  
 
- ADDITIONAL RAIN SHOWER CHANCES (50-60%) INTO FRIDAY AND  
FRIDAY NIGHT.  
 
 
   
DISCUSSION  
 
ISSUED AT 113 PM EST MON JAN 5 2026  
 
FOG, LOW STRATUS AND CHANCES FOR DRIZZLE/LIGHT RAIN WILL ENTER THE  
FORECAST LATER TONIGHT INTO TUESDAY AS LOW LEVEL MOISTURE ADVECTS  
INTO A FRONTAL WAVE TRACKING EAST THROUGH THE LOWER GREAT LAKES.  
HEIGHT FALL CENTROID AND WEAK SFC REFLECTION TRACKING THROUGH  
SOUTHERN MI SHOULD FOCUS HEAVIER PRECIPITATION NORTH OF THE AREA  
WITH MORE OF A DRIZZLE OR VERY LIGHT RAIN SETUP LOCALLY GIVEN A  
MORE SHALLOW MOISTURE PROFILE. HREF/NBM FOG PROBABILITIES ARE  
RATHER IMPRESSIVE FOR AREAS OF FOG, ESPECIALLY NORTH OF THE US  
24 CORRIDOR BETWEEN 14-21Z CLOSER TO THE SFC BOUNDARY/LOW WHERE  
A PERIOD OF DENSE FOG APPEARS POSSIBLE. THIS LOW STRATUS, FOG  
AND DRIZZLE MAY EVEN LINGER INTO TUESDAY NIGHT AS DRY/COLD  
ADVECTION IN WAKE OF THIS SYSTEM IS WEAK WITH WRAP AROUND  
MOISTURE PIVOTING THROUGH. SUBSIDENCE INVERSION COULD TRAP LOW  
CLOUDS INTO AT LEAST THE FIRST HALF OF WEDNESDAY AS LIGHT RETURN  
FLOW EVENTUALLY DEVELOPS ON THE BACKSIDE OF SFC HIGH PRESSURE.  
 
CONFIDENCE CONTINUES TO INCREASE FOR 50 DEGREE PLUS HIGH  
TEMPERATURES THURSDAY INTO FRIDAY AS SOUTHWEST FLOW DEEPENS IN  
ADVANCE OF A WESTERN CONUS LONGWAVE TROUGH. A LEAD SHORTWAVE IN  
THIS SOUTHWEST FLOW LOOKS TO BRING A GOOD SURGE OF MOISTURE  
LATE THURSDAY INTO THURSDAY NIGHT WITH PERIODS OF RAIN. A  
LEFTOVER SOUTHWEST TO NORTHEAST ORIENTED BOUNDARY FROM THE LOWER  
GREAT LAKES TO THE MID MS VALLEY THEN KEEPS CLOUDS AND CHANCES  
FOR LIGHT RAIN INTO FRIDAY. MODELS DIVERGE INTO FRIDAY NIGHT  
AND SATURDAY WITH HOW INCOMING SHORTWAVE ENERGY WITHIN THE MAIN  
UPPER TROUGH AXIS INTERACTS, AFFECTING THE POTENTIAL TRACK AND  
DEVELOPMENT (OR NOT) OF A SFC CYCLONE INTO THE GREAT LAKES.  
OPTED TO HOLD WITH THE NBM AS A RESULT WITH RAIN CHANCES FRIDAY  
NIGHT (50-60%) TRANSITIONING TO COLDER TEMPERATURES AND CHANCES  
FOR SNOW SHOWERS ON SATURDAY.  
 
 
   
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/  
 
ISSUED AT 1208 AM EST MON JAN 5 2026  
 
HIGH CLOUDS WILL DOMINATE THROUGH THE FIRST HALF OR SO OF THE  
FORECAST PERIOD. MODELS CONTINUE TO POINT TOWARDS A CLASSIC  
FOG/STRATUS SETUP AS A WARM FRONT EDGES NORTH INTO THE AREA  
TOWARDS 12Z TUE WITH A RAPID DETERIORATION IN FLIGHT CONDITIONS  
THEREAFTER, WITH KSBN LIKELY TO SEE A PERIOD OF LIFR CONDITIONS.  
SOME QUESTION AS TO EXACTLY WHEN THE PROCESS START, SO HAVE  
OPTED FOR A DOWNWARD TREND IN CONDITIONS GIVEN THE WORST  
CONDITIONS MAY END UP IN THE 14 TO 20Z TIME FRAME.  
 
 
   
IWX WATCHES/WARNINGS/ADVISORIES  
 
IN...NONE.  
OH...NONE.  
MI...NONE.  
MARINE...NONE.  
 
 
 
 
 
DISCUSSION...STEINWEDEL  
AVIATION...FISHER  
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