111  
FXUS63 KMKX 200402  
AFDMKX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI  
1002 PM CST THU DEC 19 2024  
   
KEY MESSAGES  
 
- WIDESPREAD LGT-MDT SNOWFALL WILL CONTINUE THROUGH TONIGHT WITH  
THE HEAVIEST RATES OVER EAST-CENTRAL WI VIA LAKE ENHANCEMENT.  
 
- LAKE MICHIGAN COUNTIES WILL SEE LAKE EFFECT SNOW SHOWERS  
LINGER INTO FRIDAY MORNING, POTENTIALLY IMPACTING THE MORNING  
COMMUTE. HENCE, A WINTER WEATHER ADVISORY REMAINS IN EFFECT  
LONGER (THROUGH MIDDAY FRIDAY) FOR THESE REGIONS.  
 
- THE NEXT ROUND OF ARCTIC AIR SETTLES INTO SOUTHERN WISCONSIN  
THIS WEEKEND, WITH ABOVE NORMAL TEMPERATURES RETURNING FOR  
NEXT WEEK.  
 
- THE NEXT CHANCES FOR LIGHT PRECIPITATION MONDAY INTO MONDAY  
NIGHT. MAY FALL AS RAIN DEPENDING ON SYSTEM TRACK.  
 
 
   
UPDATE  
 
ISSUED 1000 PM CST THU DEC 19 2024  
 
AN EARLIER EVENING BAND OF OVERACHIEVING MODERATE TO HEAVY SNOW  
OVER EAST-CENTRAL WISCONSIN HAS TAPERED WITH THE DEPARTURE OF A  
500 MB VORT MAX & ATTENDANT WEAKENING OF WAA & FGEN WITHIN THE  
700-500 MB LAYER. SCATTERED AREAS OF LIGHT TO MODERATE SNOW  
CONTINUE AS OF 945 PM. SURFACE ANALYSIS PLACES AN AREA OF 1016  
MB LOW PRESSURE OVER NORTH-CENTRAL ILLINOIS, WITH THE FEATURE  
FORECAST TO PROGRESS TOWARD THE FAR SOUTHERN SHORES OF LAKE  
MICHIGAN BY SUNRISE. RESULTANT TURNING OF LOW LEVEL WINDS OUT OF  
THE EAST & EVENTUALLY NORTHEAST OFF OF LAKE MICHIGAN, AS WELL AS  
ATTENDANT BOUNDARY LAYER CONVERGENCE AS FLOW MOVES ONSHORE, WILL  
SUPPORT AREAS OF LAKE-ENHANCED SNOW OVER EAST-CENTRAL AND  
SOUTHEASTERN WISCONSIN THROUGH THE OVERNIGHT AND INTO FRIDAY  
MORNING. SAID SNOW IS LIKELY TO BRING AN ADDITIONAL  
ACCUMULATIONS, THOUGH ENSEMBLE PROBABILITIES FROM THE HREF POINT  
TOWARD HOURLY RATES REMAINING AT/BELOW A HALF AN INCH. HAVE THUS  
MAINTAINED WINTER WEATHER ADVISORIES IN ADVANCE OF THIS  
ACTIVITY. WILL CONTINUE TO CLOSELY MONITOR TRENDS THROUGH THE  
OVERNIGHT HOURS AND MAKE FORECASTS ADJUSTMENTS IF NECESSARY.  
 
QUIGLEY  
 
 
   
SHORT TERM  
 
ISSUED 304 PM CST THU DEC 19 2024  
 
TONIGHT THROUGH FRIDAY NIGHT:  
 
A WELL DEFINED VORTICITY MAXIMUM IS EXITING EAST CENTRAL WI LATE  
THIS AFTERNOON, BUT A 700MB TROUGH AND ASSOCIATED WARM  
ADVECTION AND FRONTOGENESIS IS FOLLOWING IT WITH A MDT TO HEAVY  
BAND OF SNOW. THE 700 MB BAROCLINIC ZONE WILL MOVE TO CENTRAL  
WI BY EARLY EVENING THEN STALL. AN ADDITIONAL SHORTWAVE TROUGH  
CURRENTLY OVER SW MN WILL DIVE SEWD TO WEST CENTRAL IL BY 06Z  
FRI, WHILE ANOTHER UPPER WAVE OVER SRN MANITOBA WILL REACH THE  
SAME REGION BY 12Z FRI.  
 
AT THE SFC, A 1012 MB LOW PRESSURE AREA OVER NRN IA WILL TRACK  
TO CENTRAL IN BY 12Z FRI WITH NO DEEPENING EXPECTED. AS THE LOW  
PASSES TO THE SOUTH, THE BAROCLINIC ZONE OVER CENTRAL WI WILL  
SHIFT BACK SWD WITH LOW TO MID LEVEL FRONTOGENESIS EXPECTED AS  
IT DOES SO. LAKE ENHANCEMENT VIA SELY BOUNDARY LAYER FLOW  
BACKING NELY WILL LIKELY ADD A FEW INCHES OR MORE OF SNOW TO ERN  
SHEBOYGAN COUNTY THROUGH 15Z FRI. CONFIDENCE IN SEVERAL HOURS OF  
HEAVY SNOWFALL RATES IS LOW TO MDT SO WILL CONTINUE A WINTER WX  
ADVISORY FOR SHEBOYGAN AND OZAUKEE COUNTIES. ELSEWHERE, A LGT-  
MDT SNOW WILL CONTINUE THROUGH TNT GIVEN THE SUSTAINED CYCLONIC  
FLOW AND PVA THROUGH THE DEPTH OF THE TROPOSPHERE AND THE  
AFOREMENTIONED FRONTOGENESIS SHIFTING BACK SWD THROUGH THE AREA.  
THE WINTER WX ADVISORY WILL ALSO CONTINUE FOR THE REMAINING  
COUNTIES IN THE ADVISORY.  
 
SNOWFALL TOTALS FROM 18Z TODAY UNTIL 18Z FRI ARE 3-6 INCHES IN  
THE WINTER WX ADVISORY AREA WITH 5-9 INCHES OVER ERN SHEBOYGAN  
COUNTY.  
 
GEHRING  
 
 
   
LONG TERM  
 
ISSUED 304 PM CST THU DEC 19 2024  
 
SATURDAY THROUGH THURSDAY:  
 
ARCTIC HIGH PRESSURE WILL MOVE THROUGH THE UPPER GREAT LAKES  
SATURDAY. WHILE WINDS WILL BE LIGHT, TEMPERATURES WILL STRUGGLE TO  
RISE ABOVE THE UPPER TEENS TO LOW 20S. EVEN WITH STRONG HIGH  
PRESSURE, WE'LL LIKELY STILL HAVE SOME CLOUDS AROUND AS A WEAK,  
DRY SHORTWAVE PASSES OVER THE REGION.  
 
HIGH PRESSURE WILL MOVE EAST ON SUNDAY AND WAA WILL RETURN ON  
SOUTHERLY WINDS HELPING TEMPERATURES RISE INTO THE UPPER 20S TO  
LOW 30S. SUNDAY NIGHT INTO MONDAY, A WEAK SFC LOW IS EXPECTED TO  
TRACK OVER NORTHWEST AND NORTHERN WISCONSIN WITH WAA AND THE  
THERMAL RIDGE AXIS MAKING A WEST TO EAST SWIPE ACROSS THE STATE  
MONDAY MORNING INTO MONDAY AFTERNOON. AT THIS TIME, THE BETTER  
FORCING SHOULD REMAIN OVER THE NORTHERN HALF OF THE STATE CLOSER  
TO THE WAVE, LEAVING WEAKER ASCENT IN THE WAA REGIME OVER OUR CWA.  
THIS SHOULD CAUSE FAIRLY LIGHT PRECIP, WITH PREDOMINANT  
PRECIPITATION TYPES BEING A RAIN/SNOW MIX TO RAIN THROUGH MONDAY  
MORNING INTO MONDAY AFTERNOON.  
 
A WEAK COLD FRONT SHOULD PUSH THROUGH MONDAY AFTERNOON, BUT WEAK  
WAA SHOULD RETURN CHRISTMAS EVE OVER THE UPPER MIDWEST, FAILING  
TO BRING DAYTIME HIGH TEMPERATURES BACK BELOW FREEZING. A SLOW  
THAW SHOULD THEN HAPPEN THROUGH CHRISTMAS AND BEYOND AS  
TEMPERATURES REMAIN ABOVE NORMAL THROUGH THE END OF THE EXTENDED  
PERIOD.  
 
CMILLER  
 
 
   
AVIATION  
 
ISSUED 1000 PM CST THU DEC 19 2024  
 
A MIXTURE OF MVFR, IFR, AND LIFR PREVAILS THIS EVENING WITH -SN  
AND SN ONGOING ACROSS THE AREA. LIGHT TO MODERATE SNOW WILL  
CONTINUE THROUGH DAYBREAK FRIDAY, TAPERING AT WESTERN TERMINALS  
SHORTLY AFTER 12Z. -SN/SN WILL CONTINUE INTO FRIDAY MORNING AT  
LAKE MICHIGAN TERMINALS, WHERE LAKE ENHANCEMENT WILL SUPPORT  
PRECIP THROUGH MID-DAY. PASSAGE OF AN AREA OF LOW PRESSURE WILL  
RESULT IN A NORTHWEST WIND SHIFT AT ALL SOUTHERN WISCONSIN  
TERMINALS BY SUNRISE FRIDAY MORNING, WITH READINGS REMAINING  
GUSTY THROUGH THE AFTERNOON HOURS. WINDS WILL GRADUALLY TAPER  
FRIDAY EVENING AS HIGH PRESSURE APPROACHES FROM THE PLAINS.  
 
QUIGLEY  
 
 
   
MARINE  
 
ISSUED 304 PM CST THU DEC 19 2024  
 
29.9 INCH LOW PRESSURE OVER NORTHERN IOWA WILL TRACK TO INDIANA  
BY FRIDAY MORNING. THE APPROACH OF THE AFOREMENTIONED LOW PRESSURE  
WILL RESULT IN BREEZY SOUTH TO SOUTHEAST WINDS ACROSS THE OPEN  
WATERS TONIGHT. WINDS WILL SHIFT OUT OF THE NORTH-NORTHEAST BY  
DAYBREAK FRIDAY WITH NORTHERLY GUSTS UP TO 30 KNOTS THROUGH THE  
AFTERNOON. PERIODS OF SNOW WILL ACCOMPANY THE LOW PRESSURE  
SYSTEM, WITH THE BEST CHANCES FOR PRECIPITATION OVER LAKE MICHIGAN  
FORECAST FROM THIS AFTERNOON THROUGH FRIDAY MORNING. WINDS WILL  
GRADUALLY TAPER FRIDAY NIGHT AS 30.6 INCH HIGH PRESSURE BUILDS IN  
FROM THE NORTHERN GREAT PLAINS. SAID AREA OF HIGH PRESSURE WILL  
MOVE OVER LAKE MICHIGAN DURING THE DAY ON SATURDAY, ALLOWING FOR  
WINDS TO TURN OUT OF THE SOUTH-SOUTHEAST BY EARLY SUNDAY.  
 
A SMALL CRAFT ADVISORY REMAINS IN EFFECT FROM SHEBOYGAN TO  
WINTHROP HARBOR INTO FRIDAY EVENING.  
 
GEHRING  
 
 
   
MKX WATCHES/WARNINGS/ADVISORIES  
 
WI...WINTER WEATHER ADVISORY...WIZ046-WIZ047-WIZ051-WIZ056-WIZ057-  
WIZ058-WIZ062-WIZ063-WIZ064 UNTIL 6 AM FRIDAY.  
 
WINTER WEATHER ADVISORY...WIZ052-WIZ059-WIZ060-WIZ065-WIZ066-  
WIZ071-WIZ072 UNTIL NOON FRIDAY.  
 
LM...SMALL CRAFT ADVISORY...LMZ643-LMZ644 UNTIL 6 PM FRIDAY.  
 
SMALL CRAFT ADVISORY...LMZ645-LMZ646 UNTIL MIDNIGHT SATURDAY.  
 
 
 
 
 
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