812  
FXUS63 KGRB 171229  
AFDGRB  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREEN BAY WI  
629 AM CST FRI JAN 17 2025  
 
UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE  
   
KEY MESSAGES  
 
- AN ARCTIC AIRMASS REMAINS ON TRACK TO ARRIVE THIS WEEKEND.  
WIDESPREAD DANGEROUSLY COLD WIND CHILLS OF 25 TO 35 DEGREES  
BELOW ZERO, LOCALLY COLDER, APPEAR LIKELY DURING THE EARLY  
MORNING HOURS SUNDAY THROUGH TUESDAY. EXPECT COLD WEATHER  
HEADLINES TO BE FORTHCOMING.  
 
 
   
DISCUSSION  
 
ISSUED AT 319 AM CST FRI JAN 17 2025  
 
SHORT TERM...TODAY...TONIGHT...AND SATURDAY  
 
LOW LEVEL WARM ADVECTION AHEAD OF AN UPPER TROUGH AND SURFACE  
COLD FRONT SHOULD MAKE TODAY THE WARMEST DAY IN THE LAST TWO  
WEEKS, THOUGH A GUSTY WIND WILL MAKE IT FEEL COOLER THAN IT IS.  
HIGHS TODAY SHOULD RISE ABOVE FREEZING JUST ABOUT EVERYWHERE, AND  
MAY REACH 40 SOUTH OF HIGHWAY 29. THERE IS A SLIGHT CHANCE OF SNOW  
SHOWERS IN FAR NORTHCENTRAL WISCONSIN IN THE LATE AFTERNOON. A  
FEW SPRINKLES OR FLURRIES ARE NOT OUT OF THE QUESTION ELSEWHERE.  
 
THE FRONT WILL MOVE ACROSS THE AREA DURING THE AFTERNOON, BUT THE REAL  
COLD AIR WILL LAG BEHIND. IT WILL REALLY TURN COLDER OVERNIGHT, WITH  
TEMPERATURES FALLING INTO THE SINGLE NUMBERS AND TEENS BY DAWN. LAKE  
EFFECT SNOW SHOWERS ARE EXPECTED IN VILAS COUNTY, BUT SNOW ACCUMULATIONS  
SHOULD BE LESS THAN AN INCH.  
 
TEMPERATURES WILL FALL FRIDAY MORNING, AND LEVEL OFF IN THE SINGLE  
NUMBERS AND TEENS IN THE AFTERNOON. WIND CHILLS WILL BE RANGE FROM  
FIVE TO 15 BELOW ZERO. LAKE EFFECT SNOW SHOWERS WILL MOSTLY END IN  
VILAS COUNTY IN THE AFTERNOON.  
 
LONG TERM...SATURDAY NIGHT THROUGH THURSDAY  
 
FORECAST CONCERNS FOR THE EXTENDED REMAIN FRONT-LOADED ON  
DANGEROUS WIND CHILLS ACCOMPANIED BY LIKELIHOOD FOR COLD WEATHER  
HEADLINES LATE THIS WEEKEND THROUGH EARLY NEXT WEEK. NORTHWEST  
FLOW REGIME WILL BRING PERIODIC CHANCES FOR LAKE EFFECT SNOW  
SHOWERS TO THE SNOWBELTS THROUGH MID-WEEK, ALTHOUGH FOCUS WILL BE  
ON COLD-RELATED IMPACTS.  
 
TEMPERATURES/WIND CHILLS... MODELS CONTINUE TO HONE IN ON WIND  
CHILL RANGES SATURDAY NIGHT THROUGH TUESDAY. PROBABILISTIC  
GUIDANCE CURRENTLY STANDS AT A WIDESPREAD 70 TO 90 PERCENT CHANCE  
OF RECEIVING WIND CHILLS BELOW -30 DEGREES ACROSS OUR WESTERN  
TIER OF COUNTIES (SPANNING CENTRAL TO NORTH-CENTRAL WISCONSIN)  
BOTH MONDAY AND TUESDAY MORNINGS, WITH A 50 TO 70 PERCENT CHANCE  
OF GETTING BELOW -35 DEGREES. DAYTIME HIGHS WILL LIKEWISE FAIL TO  
MAKE IT ABOVE ZERO DEGREES FOR MOST, THE FIRST TIME THIS HAS  
HAPPENED SINCE 2019. AS HAS BEEN PREVIOUSLY MESSAGED, MOST OF THE  
FORECAST AREA WILL BE SOLIDLY WITHIN HEADLINE CRITERIA DURING THIS  
TIME, VERGING ON WARNING TERRITORY FOR SOME LOCATIONS.  
TEMPERATURES THEN MODERATE BACK TO POSITIVE VALUES ON WEDNESDAY AS  
UPPER-LEVEL RIDGING SHUNTS THE ARCTIC HIGH OFF TO THE EAST.  
 
 
   
AVIATION  
FOR 12Z TAF ISSUANCE  
ISSUED AT 628 AM CST FRI JAN 17 2025  
 
LOW LEVEL WIND SHEAR IS LIKELY THIS MORNING, WITH SOUTHWEST WINDS  
AROUND 50 KNOTS AT 2000 FEET AND SOUTH WINDS AROUND 10 KNOTS AT  
THE SURFACE.  
 
VFR CONDITIONS WITH MIDDLE AND HIGH CLOUDS ARE EXPECTED THROUGH  
EARLY AFTERNOON. AN APPROACHING COLD FRONT WILL BRING MVFR  
CEILINGS TO A IMT TO ISW LINE BY DUSK, WITH VFR CEILINGS TO THE  
EAST. SCATTERED LAKE EFFECT SNOW SHOWERS ARE POSSIBLE TONIGHT AND  
SATURDAY NORTH OF A RHI TO IMT LINE. A FEW SNOW FLURRIES ARE  
POSSIBLE ELSEWHERE.  
 
MVFR CEILINGS WILL LIKELY CONTINUE SATURDAY WEST OF A IMT TO STE  
LINE, WITH VFR CONDITIONS TO THE EAST.  
 
 
   
GRB WATCHES/WARNINGS/ADVISORIES  
 
NONE.  
 
 
 
 
 
DISCUSSION.....RDM/GOODIN  
AVIATION.......RDM  
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