214  
FXUS63 KIWX 100616  
AFDIWX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NORTHERN INDIANA  
116 AM EST FRI JAN 10 2025  
   
KEY MESSAGES  
 
- WIDESPREAD LIGHT SNOW (2-4") FRIDAY INTO FRIDAY NIGHT, MAINLY  
DURING THE AFTERNOON HOURS. SLIPPERY TRAVEL CONDITIONS ARE  
POSSIBLE.  
 
- CONTINUED NEAR TO BELOW NORMAL TEMPERATURES THROUGH THIS  
WEEKEND.  
 
- ARCTIC AIR AND CHANCES FOR LAKE EFFECT SNOW AND SUB-ZERO WIND  
CHILLS ARRIVE FOR THE FIRST HALF OF NEXT WEEK.  
 
 
   
UPDATE  
 
ISSUED AT 925 PM EST THU JAN 9 2025  
 
NO SIGNIFICANT CHANGES IN FORECAST THINKING THIS EVENING WITH AN  
INITIAL PERUSAL OF INCOMING 00Z DATA. LOW AND MID LEVEL  
MOISTURE TRANSPORT WILL INCREASE LATE TONIGHT INTO EARLY FRIDAY  
MORNING, PARTICULARLY ACROSS NORTHWEST INDIANA AND SOUTHWEST  
LOWER MICHIGAN. NEAR TERM GUIDANCE CONTINUES TO DEVELOP SOME  
LIGHT PRECIP AMOUNTS ALONG THIS MOISTURE TRANSPORT AXIS AND  
APPEARS TO BE TIED TO THE LEADING EDGE OF SOME WEAK MID LEVEL  
MOISTURE CONVERGENCE IN THE 700-500 MB LAYER, ALONG WITH AN  
ACTIVE ZONE OF DPVA DOWNSTREAM OF POSITIVELY TILTED UPSTREAM  
TROUGH. TIMING STILL A BIT UNCERTAIN IN TERMS OF MORNING COMMUTE  
IMPACTS, BUT CURRENT THINKING IS ANY IMPACT TO AM COMMUTE WOULD  
BE CONFINED TO THE FAR NORTHWEST FOLLOWING THE ABOVE FORCING  
MECHANISMS. FAVORABLE UPPER LEVEL DYNAMICS OVERSPREAD AREA  
FRIDAY AFTERNOON AS STRONG SHEARED VORTICITY MAX WILL ACCOMPANY  
A 140+ KNOT UPPER JET STREAK. LIMITING FACTORS FOR HIGHER  
ACCUMS THIS EVENT APPEAR TO BE NO REAL GOOD NORTHWARD MOISTURE  
TRANSPORT SURGE DUE TO POSITIVELY TILTED, PROGRESSIVE NATURE OF  
THIS TROUGH. IN TERMS OF BANDED SNOW, MARGINALLY FAVORABLE  
INGREDIENTS APPEAR TO BE CONFINED TO SOUTHEAST LOCATIONS DURING  
THE AFTERNOON HOURS ON FRIDAY, BUT ELEVATED INSTABILITY IS  
HIGHLY ELEVATED IN NATURE AND VERTICALLY OFFSET FROM STRONGER  
850-700 MB VERTICAL MOTION IN A MORE STABLE ENVIRONMENT. GIVEN  
THESE FACTORS, STILL FEEL THAT PREVIOUS FORECAST OF WIDESPREAD  
1-3" OR 2-4" ACCUMS SEEM IN ORDER AND WILL CONTINUE TO HOLD OFF  
ON HEADLINES AT THIS TIME.  
 
 
   
DISCUSSION  
 
ISSUED AT 146 PM EST THU JAN 9 2025  
 
A DEEP, VERY ELONGATED TROUGH MOVING ACROSS THE CENTRAL US  
TODAY WILL BRING MORE SNOW INTO THE AREA TOMORROW AND TOMORROW  
NIGHT. AS PREVIOUSLY MENTIONED, THIS SYSTEM WILL HAVE TWO  
POCKETS OF ENERGY. ONE OVER THE NORTHERN MIDWEST AND A MORE  
MOIST DISTURBANCE OVER THE SOUTHERN PLAINS. MOISTURE WILL  
INITIALLY BE LIMITED FOR OUR REGION WITH VERY DRY AIR CURRENTLY  
IN PLACE, AS DEWPOINTS ARE IN THE TEENS TO SINGLE DIGITS.  
THEREFORE, IT MAY TAKE SOME TIME TOMORROW MORNING FOR THE LOWER  
LEVELS TO MOISTEN UP AND ACCUMULATING SNOW TO REACH THE GROUND.  
WESTERN AREAS COULD START TO SEE SNOW DURING THE MORNING  
COMMUTE, BUT AMOUNTS SHOULD BE AN INCH OR LESS. THE BULK OF THE  
SNOW WILL ARRIVE DURING THE AFTERNOON AND EVENING, WITH MOST  
LOCATIONS SEEING ONLY 2 TO 3 INCHES. LAKE ENHANCEMENT COULD  
BRING AROUND 4 INCHES TO BERRIEN COUNTY, MICHIGAN. THE TROUGH  
WILL QUICKLY MOVE EAST ON FRIDAY NIGHT WITH JUST SOME LINGERING  
LAKE EFFECT POSSIBLE INTO SATURDAY MORNING. OTHERWISE, SATURDAY  
WILL BE DRY WITH HIGH PRESSURE BUILDING BACK IN. YET IT WILL  
REMAIN COLD ON SATURDAY WITH HIGHS MAINLY IN THE MID 20S.  
 
THE WILL BE SOME SLIGHT WARMING ON SUNDAY AND TEMPERATURES RISE  
TO AROUND 30 UNDER SOUTHWEST FLOW ALOFT. THIS WILL BE IN ADVANCE  
OF A CLIPPER SYSTEM THAT WILL BRING ANOTHER QUICK SHOT OF LIGHT  
SNOW SUNDAY NIGHT INTO MONDAY. UPPER LEVEL TROUGHING WILL THEN  
DOMINATE INTO TUESDAY WITH MUCH COLDER TEMPERATURES AND LAKE  
EFFECT SNOW. HIGHS ON TUESDAY WILL ONLY BE IN THE TEENS WITH  
WIND CHILLS IN THE LOW SINGLE DIGITS. THERE WILL BE A MINOR  
WARMING TREND GOING INTO THE MIDDLE OF NEXT WEEK, BUT  
TEMPERATURES WILL STILL REMAIN BELOW FREEZING.  
 
 
   
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/  
 
ISSUED AT 109 AM EST FRI JAN 10 2025  
 
RIDGING ACROSS THE AREA WILL CONTINUE TO MOVE EASTWARD OVERNIGHT  
AND A SOUTHERLY FLOW IN PLACE CURRENTLY IS THE HARBINGER FOR  
MOISTURE INFLUX AHEAD OF THE NEXT SYSTEM TO MOVE IN LATER TODAY  
BRINGING LIGHT SNOW THROUGH THIS EVENING WITH 2-3" OF  
ACCUMULATION WITH THIS STORM. CIGS EXPECTED TO DETERIORATE TO  
MVFR LATER THIS MORNING AND LEADING TO IFR CONDITIONS AT TIMES  
BY THIS AFTERNOON AT BOTH TAF SITES. PERIODS OF VSBY DROPPING  
BELOW 1SM THIS AFTERNOON WITH THE HEAVIER SNOW SHOWERS/BURSTS.  
SNOW WILL TAPER OFF THIS EVENING HOWEVER MVFR IN RESIDUAL  
LOWERED CIGS SHOULD PERSIST THROUGH THE REMAINDER OF THIS TAF  
PERIOD.  
 
 
   
IWX WATCHES/WARNINGS/ADVISORIES  
 
IN...NONE.  
OH...NONE.  
MI...NONE.  
MARINE...NONE.  
 
 
 
 
 
UPDATE...MARSILI  
DISCUSSION...COBB  
AVIATION...ANDERSEN  
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