287  
FXUS63 KMKX 171020  
AFDMKX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI  
420 AM CST TUE DEC 17 2024  
   
KEY MESSAGES  
 
- LIGHT SNOW IS EXPECTED THIS EVENING INTO EARLY WEDNESDAY  
MORNING ACROSS THE REGION. WIDESPREAD POTENTIAL FOR A DUSTING  
TO LESS THAN 1 INCH, WHICH COULD IMPACT THE WEDNESDAY MORNING  
COMMUTE.  
 
- COOLER MID TO LATE WEEK, WITH OVERNIGHT LOWS IN THE TEENS TO  
UPPER SINGLE DIGITS.  
 
- 60 TO 85% CHANCES FOR ACCUMULATING SNOW THURSDAY INTO THURSDAY  
NIGHT, WHICH COULD IMPACT THE THURSDAY AFTERNOON/EVENING  
COMMUTE, AND POSSIBLY THE FRIDAY MORNING COMMUTE.  
 
 
   
SHORT TERM  
 
ISSUED 415 AM CST TUE DEC 17 2024  
 
TODAY THROUGH WEDNESDAY:  
 
THOUGH A FEW BREAKS MAY DEVELOP IN THE ONGOING LOW STRATUS  
CLOUD DECK, EXPECTING MOSTLY CLOUDY CONDITIONS WITH HIGHS IN THE  
MID TO UPPER 30S TODAY. STRONG HIGH PRESSURE TRACKING ACROSS  
SOUTHERN SASKATCHEWAN CANADA WILL WORK WITH WEAK LOW PRESSURE  
TRACKING FROM THE CENTRAL PLAINS INTO THE MID ATLANTIC REGION TO  
FORM A BAND OF 700MB FRONTOGENESIS OVER OUR CWA, LEADING TO A  
LIGHT SNOWFALL EVENT ACROSS OUR CWA THIS EVENING THROUGH EARLY  
WEDNESDAY MORNING. THE ENTIRE AREA HAS POTENTIAL (50-70%) TO SEE  
AT LEAST A DUSTING OF SNOW, ONLY A ROUGHLY 15% CHANCE FOR AN  
INCH. CONFIDENCE REMAINS HIGH THAT THIS WILL BE A SNOW ONLY  
EVENT (NOT EXPECTING MIXED PRECIP). THE TIMING OF IT WOULD  
POTENTIALLY CAUSE OVERNIGHT AND EARLY WEDNESDAY AM COMMUTE  
TRAVEL IMPACTS, THE GOOD NEWS IS THAT BY 6 AM WEDNESDAY OUR  
FORECAST CALLS FOR LESS THAN 15% CHANCE OF CONTINUED PRECIP  
(FRONTOGENESIS REGION MOVES AWAY), DECREASING FURTHER THROUGHOUT  
THE DAY. NORTHWEST WINDS WITH GUSTS TO 20-25 MPH EXPECTED  
WEDNESDAY, WITH HIGHS IN THE UPPER 20S TO LOW 30S.  
 
SHEPPARD  
 
 
   
LONG TERM  
 
ISSUED 415 AM CST TUE DEC 17 2024  
 
WEDNESDAY NIGHT THROUGH MONDAY:  
 
OUR NEXT CHANCE FOR SNOW COMES FROM AN ALBERTA CLIPPER, WHICH  
CROSSES THE DAKOTAS WEDNESDAY NIGHT, PASSES OUR REGION, THEN  
REACHES THE OHIO RIVER VALLEY BY FRIDAY MORNING. THE EXACT TRACK  
REMAINS UNCERTAIN; THE CENTER OF THE LOW COULD TRACK DIRECTLY  
OVERHEAD, BUT THE MOST COMMON MODEL SOLUTION IS TO TAKE IT  
THROUGH ILLINOIS. DEPENDING ON THE TRACK, SNOW MAY BEGIN AT SOME  
POINT THURSDAY MORNING, WRAPPING UP FRIDAY MORNING. HENCE, WE  
HAVE OUR EYES ON THE THURSDAY AFTERNOON/EVENING COMMUTE AND  
POSSIBLY THE FRIDAY MORNING COMMUTE FOR POTENTIAL TRAVEL  
IMPACTS. THE WIND FIELD WITH THIS SYSTEM APPEARS RELATIVELY MILD  
(SOME GUSTS TO 25 MPH IN THE FORECAST, COULD INCREASE A BIT  
DEPENDING ON THE TRACK). PRECIP TYPE CONTINUES TO BE SNOW ONLY,  
WITH WIDESPREAD POTENTIAL FOR AN INCH OF SNOW, AND EVEN 40-75%  
CHANCES FOR 2+ INCHES NORTH OF I-94 (HIGHEST PROBS CURRENTLY  
OVER SHEBOYGAN AND OUR NORTHERN CWA). A LOT CAN CHANGE WITH  
SYSTEM TRACK, BUT THESE ARE THE CURRENT EXPECTATIONS.  
 
THE BACK SIDE OF THE LOW PRESSURE USHERS IN ANOTHER BATCH OF  
ARCTIC AIR, WITH OVERNIGHT LOWS PLUNGING INTO THE TEENS TO  
UPPER SINGLE DIGITS LATE THIS WEEK. THE GOOD NEWS IS THE CENTER  
OF THE ARCTIC HIGH PRESSURE (PASSING OVERHEAD LATE THIS WEEK /  
THIS WEEKEND) WILL KEEP WIND SPEEDS LOW AS TEMPERATURES BOTTOM  
OUT. A BRIEF / LIGHT LAKE EFFECT SNOW SHOWER IN LAKE MICHIGAN  
COUNTIES CANNOT BE COMPLETELY RULED OUT FRIDAY OR SATURDAY, BUT  
GENERALLY IT IS LOOKING DRY.  
 
SHEPPARD  
 
 
   
AVIATION  
 
ISSUED 415 AM CST TUE DEC 17 2024  
 
LOW STRATUS CLOUDS EXPECTED TO MAINTAIN OVERCAST TO BROKEN  
COVERAGE TODAY. CURRENTLY AT MVFR ALTITUDE, THOUGH A WINDOW OF  
LOW-END VFR CEILINGS COULD POSSIBLY OCCUR THIS AFTERNOON INTO  
EARLY THIS EVENING. MODEST WEST WINDS GRADUALLY DECLINE TODAY. WINDS  
BECOME LIGHT THIS EVENING, THEN TURN NORTHWEST AND ACCELERATE  
INTO WEDNESDAY.  
 
LIGHT SNOW EXPECTED THIS EVENING THROUGH EARLY WEDNESDAY  
MORNING, WITH WIDESPREAD POTENTIAL FOR AT LEAST A DUSTING OF  
SNOW, BUT CURRENTLY ONLY 15% (OR LESS) CHANCES FOR AN ENTIRE  
INCH. THE SNOW WILL BE ACCOMPANIED BY A GRADUAL DECREASE IN  
CEILING ALTITUDE, EXPECTING WIDESPREAD FUEL-ALT MVFR AND A FEW  
AREAS OF IFR CEILINGS TONIGHT INTO EARLY WEDNESDAY BEFORE THINGS  
IMPROVE.  
 
SHEPPARD  
 
 
   
MARINE  
 
ISSUED 415 AM CST TUE DEC 17 2024  
 
LOW PRESSURE OF 29.4 INCHES WILL CONTINUE NORTHEASTWARD FROM JAMES  
BAY TODAY. MEANWHILE, HIGH PRESSURE OF 30.7 INCHES ENTERS  
SOUTHERN SASKATCHEWAN CANADA. BREEZY WEST WINDS CONTINUE THIS  
MORNING, WITH A FEW GUSTS TO GALE FORCE POSSIBLE OVER THE NORTHERN  
HALF OF THE LAKE. WEST WINDS GRADUALLY DECLINE TODAY INTO  
TONIGHT.  
 
MODEST NORTHWEST WINDS EXPECTED WEDNESDAY AS THE AFOREMENTIONED  
HIGH PRESSURE SYSTEM ENTERS OUR REGION AND WEAKENS TO 30.7 INCHES.  
WINDS BECOME LIGHT AND VARIABLE EARLY THURSDAY MORNING AS THE HIGH  
PRESSURE PASSES OVERHEAD.  
 
A CLIPPER SYSTEM (FAST MOVING LOW PRESSURE AROUND 30.0 INCHES)  
WILL TRACK FROM THE DAKOTAS THROUGH OUR REGION THURSDAY / THURSDAY  
NIGHT, REACHING THE OHIO RIVER VALLEY BY FRIDAY MORNING. EXPECTING  
MODEST SOUTH TO SOUTHEAST WINDS TO DEVELOP THURSDAY AS IT  
APPROACHES, FOLLOWED BY BREEZY NORTH WINDS INTO FRIDAY AS IT  
DEPARTS. LIGHT TO MODERATE SNOW IS EXPECTED WITH THIS SYSTEM  
THURSDAY AFTERNOON THROUGH THURSDAY NIGHT.  
 
SHEPPARD  
 
 
   
MKX WATCHES/WARNINGS/ADVISORIES  
 
WI...NONE.  
LM...SMALL CRAFT ADVISORY...LMZ643 UNTIL 9 AM TUESDAY.  
 
SMALL CRAFT ADVISORY...LMZ644-LMZ645-LMZ646 UNTIL 6 AM TUESDAY.  
 
 
 
 
 
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