632  
FXUS63 KIWX 211120  
AFDIWX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NORTHERN INDIANA  
620 AM EST THU NOV 21 2024  
   
KEY MESSAGES
 
 
- SNOWSHOWERS WILL BECOME MORE WIDESPREAD THROUGH THE DAY,  
MIXING WITH RAIN IN SOME AREAS THIS AFTERNOON. HIGHEST SNOW  
ACCUMULATIONS WEST OF INDIANA 15.  
 
- SOME LAKE EFFECT RAIN SHOWERS ARE POSSIBLE FRIDAY, BUT OVERALL  
A QUIET WEEKEND APPEARS TO BE IN STORE.  
 
- RAIN CHANCES RETURN EARLY NEXT WEEK.  
 

 
   
DISCUSSION
 
 
ISSUED AT 417 AM EST THU NOV 21 2024  
 
GENERALLY LIGHT SNOWSHOWERS ARE IMPACTING MANY AREAS AS THE  
POCKET OF COLDER AIR, COMBINED WITH A DISTURBANCE CLIPPING SW  
AREAS, AID IN INCREASED LIFT. THUS FAR NO IMPACTS HAVE BEEN  
REPORTED WITH SOME SPOTS LIKELY SEEING A DUSTING OR MAYBE TENTH  
OF SNOW. THE EXCEPTION MAY BE CLOSER TO LK MI WHERE SOMEWHAT  
HEAVIER SHOWERS EXISTED AS LAKE ENHANCEMENT WAS HELPING. QPF  
AMOUNTS FROM KBEH HAVE NOT BEEN OVERLY IMPRESSIVE SO FAR, WITH  
MDOT PLOW AND STATIONARY CAMERAS SHOWING MAYBE A FEW TENTHS TO  
LOCALLY AN INCH.  
 
THE UPPER LEVEL LOW IS SLOWLY WORKING ACROSS CENTRAL LOWER MI  
WITH THE SFC LOW MOVING ACROSS THE EASTERN UP OF MI. MODELS HAVE  
BEEN PRETTY PRONOUNCED ON COVERAGE, INTENSITY AND QPF POTENTIAL  
AS THE LOW DROPS SOUTH DOWN THE HEART OF LAKE MI TODAY, REACHING  
NW AREAS LATER THIS MORNING (16Z OR SO) AND THEN EXISTING THE  
SOUTH NEAR 00Z FRI. CONCERNED THAT QPF MAY BE WAY OVERDONE GIVEN  
A CLOSE LOOK AT OBSERVATIONS IN THE UP WHERE THE HEAVIEST  
PRECIP IS SUPPOSED TO EXIST PER THE MODELS. THE SFC LOW WILL BE  
SLOWLY WEAKENING AS IT DROPS SOUTH, BUT STILL HAVE A FAIR AMOUNT  
OF ENERGY AND MOISTURE ACCOMPANYING IT. THE BIGGEST CHANGES FOR  
NOW WAS TO LIMIT THE EASTERN EDGE OF THE HIGHEST POPS AS THE  
BULK OF THE PRECIP LOOKS TO REMAIN ALONG/WEST OF INDIANA 15. QPF  
AMOUNTS WERE LOWERED SOME, BUT NOT SUBSTANTIALLY FOR NOW,  
YIELDING SLIGHTLY LOWER ACCUMULATIONS WEST (STILL IN THE 1 TO  
MAYBE 2 INCH RANGE). MODEL TRENDS HAVE ALSO SHOWED SOMEWHAT  
HIGHER AFTERNOON TEMPS WITH EVEN A DEGREE OR 2 WARMER IMPACTING  
THE OVERALL ACCUMULATION. AS THE AREA OF PRECIP COMES THROUGH,  
EXPECT REDUCED VISIBILITY AND IN AREAS THAT SEE SNOWFALL,  
ACCUMULATIONS WOULD OCCUR ON GRASSY AND ELEVATED AREAS. ROAD  
TEMPERATURE FORECASTS SUGGEST READINGS IN THE 40S DURING THE  
PEAK OF THE EVENT, MEANING ROADS SHOULD BE WET. WHILE IT WILL BE  
BREEZY TODAY THE SFC LOW TRACK WILL PUSH THE STRONGEST PRESSURE  
GRADIENT WEST OF THE AREA (WHERE WIND ADVISORIES HAVE BEEN  
ISSUED ACROSS IL). STRONGEST WINDS FOR OUR AREA WILL BE BOTH  
AHEAD OF AND BEHIND THE LOW, WITH GUSTS OF 35 TO MAYBE 40 MPH IN  
THE WEST.  
 
SIGNIFICANT CHANGES MADE FOR TONIGHT TO TREND MUCH DRIER AND  
ALSO COLDER AS SUBSIDENCE ARRIVES IN THE WAKE OF THE LOW AND  
MAYBE EVEN SOME BREAKS OR THINNING OF THE CLOUDS. LOWS WILL BE  
IN THE UPPER 20S NE TO NEAR FREEZING WEST, SO ANY WET ROADS  
COULD FREEZE IN SPOTS (ALTHOUGH SUSPECT MINIMAL IF ANY IMPACTS).  
LAKE EFFECT SHOWERS WILL BE POSSIBLE ON FRIDAY AS ANOTHER  
DISTURBANCE DROPS SOUTH. THERMAL PROFILES SUPPORT ALL RAIN WITH  
OVERALL INTENSITY LIKELY NOT VERY HIGH AS DELTA TS ARE CLOSER TO  
12 TO 14 C (ENOUGH FOR LAKE EFFECT, BUT NOT IDEAL FOR HEAVIER  
PRECIP). IN ADDITION, INVERSION HEIGHTS WILL BE LOWER (7 TO  
8KFT).  
 
WITH FOCUS ON THE NEXT 24 TO 36 HOURS, LITTLE WAS MODIFIED IN  
THE EXTENDED PERIOD (SAT-THU) WITH THE WEEKEND LIKELY DRY AND  
WARMER (ABOVE NORMAL), FOLLOWED BY A NORTHERN STREAM WAVE THAT  
MAY BRING SOME RAIN OR SNOW CHANCES MID TO LATE WEEK.  
 

 
   
AVIATION /12Z TAFS THROUGH 12Z FRIDAY/
 
 
ISSUED AT 620 AM EST THU NOV 21 2024  
 
SCT, MAINLY MVFR, SNOW SHOWERS WILL CONTINUE DURING THE NEXT  
FEW HOURS UNTIL PRIMARY VORT MAX AND SURFACE LOW DIVE SOUTH INTO  
THE AREA THIS AFTERNOON. THIS WILL PRIMARILY IMPACT KSBN WITH  
VISIBILITIES BELOW 1SM LIKELY FOR SEVERAL HOURS IN THE 16-22Z  
WINDOW. LESSER IMPACTS ANTICIPATED AT KFWA BUT PERIODS OF IFR  
ARE POSSIBLE THERE AS WELL. IMPROVEMENT ANTICIPATED DURING THE  
EVENING HOURS WITH RETURN TO VFR POSSIBLE. HOWEVER, LAKE EFFECT  
STRATUS WILL BUILD AGAIN BY EARLY FRIDAY WITH MVFR CONDITIONS  
LIKELY ONCE AGAIN.  
 

 
   
IWX WATCHES/WARNINGS/ADVISORIES
 
 
IN...NONE.  
OH...NONE.  
MI...NONE.  
MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EST THIS MORNING FOR LMZ043-  
046.  
GALE WARNING UNTIL 1 AM EST FRIDAY FOR LMZ043-046.  
 

 
 

 
 
DISCUSSION...FISHER  
AVIATION...AGD  
 
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