354
FXUS63 KGRB 220351
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
951 PM CST SUN DEC 21 2025
NEW INFORMATION ADDED TO UPDATE SECTION
UPDATE
ISSUED AT 950 PM CST SUN DEC 21 2025
HAVE NOTED MINOR SHIFT SOUTHWARD IN THE 18Z/00Z GUIDANCE WITH
EXPECTED MID-LEVEL FRONTOGENETIC SNOW BAND. NOW APPEARS THE AXIS
OF SNOW IMPACTS THE HIGHWAY 29 CORRIDOR, STARTING 5-6A AND LASTING
THROUGH 9-10A. SNOWFALL RATES UP TO 0.5" PER HOUR WILL IMPACT THE
MONDAY MORNING COMMUTE. BAND IS TRANSIENT AND SLRS LOWER AT 8-10:1,
SO STILL THINK OVERALL SNOW TOTALS WILL END UP IN THE 1-2" RANGE,
THOUGH IT IS NOT OUT OF THE QUESTION SNOWFALL IN THE NARROWEST
BAND ENDS UP MORE IN 2-3" RANGE. FORECAST SOUNDINGS STILL INDICATE
WARM LAYER CENTERED AT 925MB. GREATEST RISK OF THIS IS FROM
WAUSHARA COUNTY INTO SOUTHERN FOX VALLEY AND EAST TO THE LAKESHORE.
THERE IS ALSO STILL POTENTIAL THE PRECIP WILL TRY TO END FROM THE
SOUTH AS ICE ALOFT IS STRIPPED AWAY. GIVEN THE LIGHT SNOW, POTENTIAL
MIX ALL COMING TOGETHER FOR THE MORNING COMMUTE, ISSUED SPS TO GIVE
THOSE TRAVELING TO WORK/SCHOOL A HEADS-UP THE MORNING COMMUTE COULD
BE SLIPPERY AND SLOW.
KEY MESSAGES
- ROUND OF SNOW WILL SPREAD INTO THE REGION LATE TONIGHT INTO
MONDAY MORNING. A NARROW SWATH OF 1-3" IS POSSIBLE ALONG AND
NORTH OF HWY 29 INTO DOOR CO. LESSER AMOUNTS UNDER 1" FURTHER
NORTH AND SOUTH. LINGERING PRECIPITATION MAY SEE A BRIEF WINTRY
MIX DURING THE AFTERNOON HOURS MONDAY.
- ABOVE NORMAL TEMPERATURES EXPECTED THROUGH THE WORK WEEK.
DISCUSSION
ISSUED AT 119 PM CST SUN DEC 21 2025
REST OF TODAY...
QUIET CONDITIONS WILL REMAIN TO CLOSE OUT THE WEEKEND. MID-LEVEL
CLOUDS STREAMING OVER THE REGION SHOULD CLEAR OUT THIS EVENING
LEAVING MOSTLY CLEAR SKIES. TEMPERATURS IN THE TEENS TO LOW 20S
ACROSS THE REGION THIS AFTERNOON MAY COOL A FEW DEGREES AFTER
SUNSET, HOWEVER, AS WARM AIR ADVECTION STRENGTHENS OVERNIGHT
TEMPERATURES WILL RISE.
MONDAY SNOW CHANCES...
CAMS SHOW SNOW BLOSSOMING SHORTLY AFTER MIDNIGHT TONIGHT ACROSS
CENTRAL WI AS A LEFT ENTRANCE REGION ARRIVES TO SUPPORT ASCENT
ASSOCIATED WITH LOW AND MID LEVEL WARM AIR ADVECTION AND A
DEVELOPING LLJ. FORECAST SOUNDINGS SUPPORT SNOW BEING THE DOMINATE P-
TYPE DURING THE ONSET OF THIS EVENT FOR MUCH OF THE REGION, HOWEVER,
A WEAK WARM NOISE COULD LEAD TO ISOLATED POCKETS OF SNOW MIXED WITH
FREEZING RAIN ACROSS CENTRAL WI. AS PROFILES SATURATE THE RISK FOR
FREEZING RAIN DIMINISHES THROUGH MONDAY MORNING. A BAND OF MODERATE
SNOWFALL (UP TO 0.5" PER HOUR) IS EXPECTED TO BE FOCUSED ALONG AN
AREA OF MID-LEVEL F-GEN STRETCHING FROM CENTRAL TO FAR NORTHEAST WI.
TIMING OF THOSE HIGHER SNOWFALL RATES IS GENERALLY EXPECTED BETWEEN
6AM AND NOON. ACCUMULATIONS ARE EXPECTED TO BE GREATEST (1-3")
WITHING A NARROW CORRIDOR GENERALLY ALONG AND NORTH OF HWY29 INTO
DOOR CO. LESSER AMOUNTS, UNDER 1" ARE EXPECTED ACROSS THE FOX VALLEY
AND NORTH OF HWY 8. IMPACTS FROM THIS EVENT MAY BE SLIGHTLY
INCREASED DUE TO THE TIMING OF THE HEAVIEST SNOW COINCIDING WITH
THE MONDAY AM COMMUTE. IF YOU ARE COMMUTING MONDAY MORNING GIVE
YOURSELF EXTRA TIME TO REACH YOUR DESTINATION.
AS MOISTURE GETS STRIPPED OUT OF THE COLUMN MONDAY AFTERNOON THERE
MAY BE A BRIEF WINDOW FOR FREEZING DRIZZLE TO DEVELOP ACROSS EAST-
CENTRAL WI. HOWEVER, WITH ANY FREEZING DRIZZLE FALLING ON FRESH SNOW
OR TREATED ROADS IMPACTS SHOULD BE MINIMIZED. ANY UNTREATED ROADS
COULD SEE A FEW ISOLATED SLIPPERY SPOTS IMPACT THE MONDAY PM
COMMUTE.
MILD CONDITIONS REST OF THE WEEK...
HEIGHT RISES BEHIND THE DEPARTING SNOW WILL USHER SEASONALLY WARM
TEMPERATURES BACK INTO THE REGION BEGINNING TUESDAY. WITH UPPER-LEVEL
FLOW THEN BECOMING MORE ZONAL THROUGH THE MIDDLE OF THE WEEK
TEMPERATURES WILL LIKELY RUN 5-10 DEGREES WARMER WITH HIGHS IN THE
MIDDLE TO UPPER 30S THROUGH THE END OF THE WEEK.
GEFS/ENS HINT AT ANOTHER CHANCE FOR WIDESPREAD PRECIPITATION COMING
LATER IN THE WEEK AS THE NEXT TROUGH DIGS INTO THE WESTERN GREAT
LAKES. ENS SOUNDINGS AND METEOGRAMS SHOW THE POTENTIAL FOR THIS TO BE
A MESSY MIXED PRECIPITATION EVENT ACROSS THE NORTHERN HALF OF
WISCONSIN. HOWEVER, CLUSTER ANALYSIS OF 500MB GLOBAL ENSEMBLES FLOW
FIELDS SHOWS THE PATTERN BEGINNING TO DIVERGE SIGNIFICANTLY TOWARD
THE END OF NEXT WEEK AND INTO NEXT WEEKEND WHICH IS LEADING TO LOW
FORECAST CONFIDENCE FOR THIS PERIOD AT THIS TIME. WILL NEED TO WATCH
THIS PERIOD CLOSELY AS A MESSY MIXED PRECIPITATION EVENT WOULD
IMPACT POST CHRISTMAS TRAVEL.
AVIATION
FOR 00Z TAF ISSUANCE
ISSUED AT 605 PM CST SUN DEC 21 2025
EXPECT VFR CONDITIONS THROUGH THE NIGHT WITH INCREASING MID
CLOUDS FROM THE SOUTHWEST. STRENGTHENING WINDS JUST ABOVE THE
SURFACE WILL CREATE LLWS AT ALL THE TAF SITES THROUGH MONDAY
MORNING.
A ROUND OF SNOW WILL MOVE NORTH INTO CENTRAL WI LATE TONIGHT AND
CONTINUE SPREADING NORTH THROUGH EARLY MONDAY AFTERNOON, BEFORE
SHIFTING EAST AND ENDING. CIGS WILL DROP TO MVFR AS THE SNOW MOVES
THROUGH, WITH IFR OVER NORTH-CENTRAL WI. EXPECT A 2-4HR PERIOD OF
MODERATE SNOW WITH IFR VISIBILITY FOR ALL SITES EXCEPT RHI. ENOUGH
CONFIDENCE IN THIS TO INCLUDE THIS IN TAFS AS PREVAILING CONDITION.
FOR GROUND OPERATIONS SNOW ACCUMULATIONS OF AROUND 1" ARE EXPECTED
AT MOST TERMINALS, HOWEVER, A NARROW SWATH OF 1-3" IS POSSIBLE NORTH
OF A CWA TO GRB LINE.
GRB WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE.........JLA
DISCUSSION.....GK
AVIATION.......JLA
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