820
FXUS63 KGRB 171755
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1155 AM CST WED DEC 17 2025
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE
KEY MESSAGES
- MIX OF RAIN, FREEZING RAIN AND SNOW EXPECTED WEDNESDAY NIGHT
INTO EARLY THURSDAY, THEN RAIN CHANGING TO SNOW THURSDAY
AFTERNOON AND EVENING. FLASH FREEZE POSSIBLE LATE THURSDAY
AFTERNOON AND EVENING. TRAVEL CONCERNS FROM LATE WEDNESDAY
NIGHT THROUGH THURSDAY NIGHT.
- LIGHT SNOW POSSIBLE FRIDAY NIGHT INTO SATURDAY MORNING.
- PERIODIC WINDY CONDITIONS AND A CHANCE OF GALES ON LAKE MICHIGAN
THROUGH THE REST OF THE WORK WEEK.
DISCUSSION
ISSUED AT 259 AM CST WED DEC 17 2025
MAIN FOCUS OF THE FORECAST WILL BE ON THE UPCOMING WINTRY SYSTEM
SET TO ARRIVE LATE TONIGHT INTO THURSDAY. FOLLOWING THIS, ANOTHER
ROUND OF SNOW OR TWO WILL ALSO BE IN THE WORKS FOR THE END OF THE
WEEK INTO THE WEEKEND AS THE NEXT CLIPPER ARRIVES.
ACTIVE WEATHER LATE TONIGHT THRU THURSDAY...
A STRONG LOW PRESSURE SYSTEM WILL TRACK ACROSS THE WESTERN GREAT
LAKES LATE TONIGHT THROUGH THURSDAY. PRECIPITATION TYPE REMAINS
THE MOST CHALLENGING ASPECT OF THE FORECAST, SPECIFICALLY ON THE
WHEN/WHERE TRANSITION OCCURS. INITIAL ONSET OF THE SYSTEM EARLY
THURSDAY MORNING WILL FEATURE A WINTRY MIX WITH SNOW GIVING WAY TO
RAIN AS WARMER AIR INTRUDES IN THE MID LEVELS AND ICE BECOMES
SCARCE. FREEZING RAIN POTENTIAL REMAINS LIMITED MAINLY BY SURFACE
TEMPERATURES AND HOW QUICKLY THESE WARM. SUSPECT THAT PRIOR ROAD
TREATMENTS, STRONG NON-DIURNAL WARMING PUSHING AIR TEMPS INTO THE
30S, AND TIMING DISCREPANCIES FOR PRECIP ONSET WILL LARGELY SPARE
THE FOX VALLEY AND AREAS EASTWARDS FROM A FREEZING RAIN THREAT, SO
REMOVED THESE AREAS FOR THE MORNING PERIOD. HOWEVER, PORTIONS OF
CENTRAL, NORTH- CENTRAL, AND NORTHEASTERN WISCONSIN WILL STILL SEE
A WINDOW FOR FREEZING PRECIPITATION THROUGH THE MID-MORNING BEFORE
THIS CONCERN ENDS. ICE ACCUMULATIONS SHOULD STAY IN THE REALM OF A
COUPLE HUNDRETHS WHICH WILL LIKELY BE TOO MINOR TO POSE AN
INFRASTRUCTURE CONCERN, BUT ANY ICING WILL BE A TRAVEL CONCERN.
RAIN WILL BECOME THE PREDOMINANT PRECIPITATION FOR THE LATE
MORNING TO EARLY AFTERNOON FOR ALL BUT FAR NORTHERN WISCONSIN
BEFORE SNOW WORKS ITS WAY IN WITH THE COLDER AIR. SNOW TOTALS
REMAIN AROUND AN INCH OR LESS FOR MOST OF THE AREA, EXCEPT FAR
NORTHERN WISCONSIN WHERE TOTALS COULD GET UP TO A FEW INCHES FROM
BOTH LAKE ENHANCEMENT AND SNOW BEING THE MORE DOMINANT P-TYPE.
FINALLY, TIMING ON WHEN THE COLDEST AIR RETURNS THURSDAY EVENING
REMAINS UNCERTAIN BUT THERE IS POTENTIAL FOR A RAPID FALL IN
TEMPERATURES WHICH COULD PRODUCE ADDITIONAL ICY SPOTS ON UNTREATED
SURFACES. THIS WILL ALSO BE ANOTHER PERIOD OF STRONGER WIND GUSTS
IN THE REGION. ULTIMATELY, ALL OF THIS WILL MAKE FOR A PERIOD OF
HAZARDOUS TRAVEL, SO MAKE SURE TO BE READY FOR CHANGES IN ROAD
CONDITIONS ESPECIALLY IF TRAVELING VERY EARLY THURSDAY OR LATE
THURSDAY EVENING.
NEXT CLIPPER LATE FRIDAY INTO SATURDAY...
ANOTHER CLIPPER WILL CROSS THE GREAT LAKES REGION OVERNIGHT FRIDAY
INTO SATURDAY, BRINGING WITH IT ANOTHER ROUND OF LIGHT SNOWFALL.
AMOUNTS WILL LIKELY BE HIGHER IN NORTHERN WISCONSIN BUT OVERALL
SHOULD STILL REMAIN RELATIVELY LIGHT.
AVIATION
FOR 18Z TAF ISSUANCE
ISSUED AT 1143 AM CST WED DEC 17 2025
LOW CLOUDS HAVE SHIFTED NORTH AND EAST OF THE REGION, LEAVING
CLEAR SKIES AT ISSUANCE TIME. A BATCH OF MID-LEVEL CLOUDS WAS
APPROACHING FROM MN, AND THESE WILL IMPACT THE FORECAST AREA
LATER THIS AFTERNOON AND EVENING.
ATTENTION THEN TURNS TO A WINTRY SYSTEM THAT ARRIVES LATE TONIGHT,
MAINLY AFTER 08Z/THU. AT INITIAL ONSET, A MIX OF LIGHT RAIN OR
FREEZING RAIN IS EXPECTED, WITH FREEZING RAIN POTENTIAL MAINLY
DEPENDENT ON PAVEMENT TEMPERATURES, WHICH ARE DIFFICULT TO
DISCERN AT THIS TIME. WILL INCLUDE A MENTION OF FZRA AT THE
WESTERN TAF SITES LATE TONIGHT, WITH A TRANSITION TO A RAIN/SNOW
MIX THURSDAY MORNING. FARTHER EAST, THE PRECIPITATION TYPE SHOULD
BE ALL RAIN, WITH THE PREVIOUSLY-MENTIONED CAVEAT REGARDING
PAVEMENT TEMPERATURES. CEILINGS WILL QUICKLY DROP TO MVFR/IFR LATE
TONIGHT, AND COULD DROP TO LIFR THURSDAY MORNING. AREAS OF FOG
WILL ALSO FORM AS WARM AIR OVERRIDES THE SNOW PACK AND FROZEN
GROUND.
STRONG WINDS ALOFT WILL DEVELOP THIS EVENING AND CONTINUE THROUGH
MOST OF THE TAF PERIOD, LEADING TO WIDESPREAD STRONG LLWS. GUSTY
SOUTH SURFACE WINDS WILL DEVELOP TONIGHT, THEN BECOME SOUTHWEST
THURSDAY MORNING.
GRB WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION.....UHLMANN
AVIATION.......KIECKBUSCH
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