048  
FXUS63 KIWX 261139  
AFDIWX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NORTHERN INDIANA  
639 AM EST TUE JAN 26 2021  
   
SYNOPSIS
 
 
ISSUED AT 527 AM EST TUE JAN 26 2021  
 
A WINTRY MIX OF LIGHT SNOW AND FREEZING DRIZZLE OR DRIZZLE WILL  
CONTINUE THROUGH THE EVENING. ROADS MAY BE SLICK FOR THE MORNING  
COMMUTE. OTHERWISE, EXPECT MOSTLY CLOUDY SKIES WITH HIGHS IN THE  
30S. MOSTLY DRY CONDITIONS ARE EXPECTED OVERNIGHT, WITH LOWS FALLING  
INTO THE UPPER TEENS AND LOW TO MID 20S. LAKE EFFECT SNOW SHOWERS  
ARE LIKELY NEAR LAKE MICHIGAN WEDNESDAY INTO THURSDAY, WITH PARTLY  
TO MOSTLY CLOUDY SKIES EXPECTED ELSEWHERE. HIGHS WILL BE IN THE 20S  
AND LOW 30S. LOWS WILL BE IN THE SINGLE DIGITS AND TEENS. DRY  
CONDITIONS ARE EXPECTED FRIDAY.  
 

 
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 527 AM EST TUE JAN 26 2021  
THE WINTER WEATHER ADVISORY REMAINS IN EFFECT THROUGH THIS  
AFTERNOON. FORECAST LOOKS LARGELY ON TRACK. AREAS OF LIGHT FREEZING  
DRIZZLE AND SNOW, OR DRIZZLE (FURTHER SOUTHEAST) WILL CONTINUE  
THROUGH THE DAY FOR MOST AREAS, WITH CHANCES FOR MOSTLY SNOW  
CONTINUING IN THE FAR NORTHWESTERN CWA WITH THE DEFORMATION ZONE OF  
THE LOW PRESSURE SYSTEM MOVING IN. HAVE AN ADDITIONAL 1 TO 2 INCHES  
FOR MAINLY SOUTHWEST LOWER MICHIGAN/FAR NW IN COUNTIES. AFTER THE  
DRY SLOT EXITS THE AREA AND WE SEE A RETURN OF SOME OF THE DEEPER  
MOISTURE/ICE IN THE CLOUD LATER THIS AFTERNOON WE WILL SEE A CHANGE  
OVER BACK TO LIGHT SNOW. THE MORNING COMMUTE WILL BE HAZARDOUS THIS  
MORNING GIVEN THE SNOW AND ICE ACCUMULATIONS WE HAD OVERNIGHT. THERE  
IS A LITTLE BIT OF FOG (BR) AROUND, THOUGH THE DENSER FOG IS FURTHER  
SOUTH OF OUR CWA, AND I'M UNCERTAIN AS TO WHETHER IT WILL MAKE IT  
THIS FAR NORTH. MOST OF THE VISIBILITIES ARE CURRENTLY BETWEEN 2-5  
MILES, SO OPTED TO LEAVE OUT OF THE FORECAST FOR NOW. HIGH  
TEMPERATURES WILL LINGER AROUND FREEZING IN OUR NORTHWEST, AND  
INCREASE INTO THE MID 30S GENERALLY SOUTH OF US 24. THIS WILL CAUSE  
MORE OF A DRIZZLE (VS FREEZING DRIZZLE) BEFORE COLDER AIR SINKS  
FURTHER SOUTHEASTWARD AND WE SEE SOME LIGHT SNOW SHOWERS INTO THE  
EVENING.  
 
WE'LL SEE A BREAK IN THE PRECIPITATION LATER TONIGHT INTO WEDNESDAY  
MORNING BEFORE LAKE EFFECT SNOW CHANCES MOVE IN. WINDS WILL REMAIN  
OUT OF THE NORTHEAST THROUGH THE NIGHT, WHICH SHOULD PRECLUDE ANY  
LAKE EFFECT THAT DEVELOPS OVER CHICAGO'S AREA FROM SHIFTING INTO OUR  
NORTHWESTERN COUNTIES. EXPECT MOSTLY CLOUDY SKIES OVERNIGHT WITH  
LOWS FALLING INTO THE TEENS AND LOW TO MID 20S.  
 

 
   
LONG TERM
 
(WEDNESDAY THROUGH MONDAY)  
ISSUED AT 527 AM EST TUE JAN 26 2021  
 
WEDNESDAY INTO THURSDAY WE'LL SEE MOSTLY DRY CONDITIONS BEYOND SOME  
LAKE EFFECT. NORTHEASTERLY WINDS WILL GRADUALLY SHIFT MORE NORTHERLY  
BY WEDNESDAY AFTERNOON BEHIND AN UPPER LEVEL TROUGH, WHICH WILL  
REORIENT THE LAKE ENHANCED SNOW BAND OVER CHICAGO TO BE MORE NORTH-  
SOUTH (VS SW TO NE) AND SHIFT IT INTO OUR AREA. GIVEN THE LONG FETCH  
ACROSS LAKE MI, INVERSION HEIGHTS AROUND 5-6KFT, THE UPPER LEVEL  
WAVE MOVING THROUGH, AND DECENT DELTA THETA-E VALUES THROUGH EARLY  
THURSDAY I OPTED TO INCREASE POPS TO LIKELY OR HIGH CHANCE. HIGH  
PRESSURE WILL BUILD IN FROM THE WEST BY THURSDAY AFTERNOON, BRINGING  
IN DRIER AIR AND LOWER INVERSION HEIGHTS. WINDS WILL ALSO GRADUALLY  
SHIFT TO THE WEST, BLOWING THE BAND FURTHER INLAND TO THE EAST  
BEFORE IT DISSIPATES ALTOGETHER. EXPECT AROUND 1 TO 2 INCHES OF SNOW  
NEAR LAKE MICHIGAN, WITH TRACE AMOUNTS ELSEWHERE FROM WEDNESDAY INTO  
THURSDAY. IT WILL BE COLDER, WITH HIGH TEMPERATURES IN THE 20S AND  
LOW 30S. LOWS WILL BE IN THE SINGLE DIGITS AND TEENS.  
 
AS FOR ANY SYNOPTIC SNOW WITH THE UPPER LEVEL TROUGH WEDNESDAY,  
OPTED TO KEEP ONLY SLIGHT CHANCES FOR SNOW IN THE FAR SOUTH. MOST OF  
THE GUIDANCE KEEPS DEVELOPING PRECIPITATION WELL SOUTH OF US, BUT  
THE ECMWF (AND THE NAM) STILL GRAZES OUR BORDER WITH LIGHT QPF  
DURING THE AFTERNOON HOURS (MOVING WEST TO EAST). CONFIDENCE IS NOT  
HIGH IN THIS OCCURRING.  
 
THURSDAY NIGHT INTO SATURDAY MORNING HIGH PRESSURE BUILDS IN  
OVERHEAD, BRINGING DRY CONDITIONS AND PARTLY TO MOSTLY SUNNY SKIES.  
HIGHS FRIDAY WILL BE IN THE MID-UPPER 20S AND LOW TO MID 30S  
(WARMEST FAR SOUTHWEST). LOWS WILL BE IN THE TEENS AND 20S.  
 
FOR THE WEEKEND AND START OF NEXT WEEK, THE UPPER LEVEL RIDGE WILL  
AMPLIFY IN RESPONSE TO A DIGGING TROUGH (OR CLOSED LOW) DIVING INTO  
THE CENTRAL PLAINS. KEPT CONSENSUS POPS (LIKELY TO CHANCE) SATURDAY  
INTO MONDAY AS THE SURFACE LOW ASSOCIATED WITH THE UPPER LEVEL  
TROUGH SHIFTS EAST-NORTHEAST FROM MO INTO NORTHERN IN/OH. THERE ARE  
SIGNIFICANT TIMING AND EVOLUTION DIFFERENCES BETWEEN MODELS AT THIS  
POINT, BUT HAVE CHANCES FOR RAIN AND SNOW THROUGH THE PERIOD,  
HIGHEST ON SATURDAY AHEAD OF THE WARM FRONT AND THEN AGAIN ON THE  
BACKSIDE OF THE LOW FOR SUNDAY INTO MONDAY (MONDAY IS SLIGHT  
CHANCES). IT WILL BE SLIGHTLY WARMER, WITH HIGHS IN THE LOW TO MID  
30S NORTH AND CENTRAL, AND MID TO UPPER 30S SOUTH.  
 
ANOTHER UPPER LEVEL RIDGE/SURFACE HIGH BUILDS IN BEHIND THE SYSTEM  
FOR MONDAY NIGHT INTO TUESDAY, BRINGING A RETURN TO DRY  
CONDITIONS.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)  
ISSUED AT 639 AM EST TUE JAN 26 2021  
 
IFR/LIFR CONDITIONS WILL PERSIST THROUGH MUCH OF TODAY WITH  
MOISTURE-LADEN LOW LEVEL TROUGH REMAINING OVER THE AREA UNTIL LATE  
EVENING. VERY LIGHT FREEZING DRIZZLE WILL CONTINUE THROUGH THE  
MORNING (MIXING WITH SNOW AT KSBN) BUT VERY LITTLE ADDITIONAL  
ACCUMULATION IS EXPECTED BEFORE PRECIP TAPERS OFF DURING THE LATE  
AFTERNOON. SOME POTENTIAL FOR VISIBILITIES TO DROP BELOW 1SM AT  
KFWA LATER THIS MORNING BUT CONFIDENCE IS NOT HIGH AND IMPACTS  
WILL BE LARGELY DRIVEN BY VERY LOW STRATUS ANYWAY (POTENTIALLY  
DROPPING TO 300 FT FOR A TIME THIS MORNING). SLOW IMPROVEMENT  
ANTICIPATED INTO THE EVENING AS TROUGH EXITS AND DRIER AIR BEGINS  
TO FILTER SOUTH. MAY RETURN TO VFR BY 09Z WEDNESDAY (PARTICULARLY  
AT KSBN) BUT WILL HOLD OFF ONE MORE CYCLE BEFORE ADDING THAT  
TRANSITION.  
 

 
   
IWX WATCHES/WARNINGS/ADVISORIES
 
 
IN...WINTER WEATHER ADVISORY UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON  
FOR INZ003>009-012>018-020-022>027-032>034.  
 
MI...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR  
MIZ077>081.  
 
OH...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR OHZ001-  
002-004-005-015-016-024-025.  
 
LM...SMALL CRAFT ADVISORY UNTIL 10 AM EST THURSDAY FOR LMZ043-046.  
 

 
 

 
 
SYNOPSIS...MCD  
SHORT TERM...MCD  
LONG TERM...MCD  
AVIATION...AGD  
 
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