506
FXUS63 KGRB 130529
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1129 PM CST FRI DEC 12 2025
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
KEY MESSAGES
- LIGHT SNOW MIXED WITH FREEZING DRIZZLE WILL CONTINUE TO CREATE
SCATTERED SLIPPERY STRETCHES ON AREA ROADS THROUGH LATE THIS
AFTERNOON.
- A SURGE OF BITTERLY COLD ARCTIC AIR WILL IMPACT THE REGION
TONIGHT INTO SUNDAY MORNING. WIND CHILLS WILL PLUMMET TO 20 TO
30 DEGREES BELOW ZERO LATE TONIGHT AND REMAIN DANGEROUS THROUGH
SUNDAY MORNING FOR MOST AREAS.
- A WARMING TREND DEVELOPS TUESDAY AND WEDNESDAY, FOLLOWED BY A
POTENT SYSTEM THAT BRINGS THE POTENTIAL FOR A WINTRY MIX, RAIN,
AND GUSTY WINDS WEDNESDAY NIGHT INTO THURSDAY.
DISCUSSION
ISSUED AT 227 PM CST FRI DEC 12 2025
THE LATEST RAP ANALYSIS INDICATES POTENT SHORTWAVE ENERGY LOCATED
NORTH OF INTERNATIONAL FALLS, WHICH IS DRIVING A COLD FRONT
ACROSS FAR WESTERN WISCONSIN EARLY THIS AFTERNOON. AHEAD OF THIS
BOUNDARY, A BAND OF WINTRY PRECIPITATION IS TRAVERSING NORTHEAST
WISCONSIN. EMBEDDED HEAVIER SNOW SHOWERS WITHIN THIS BAND HAVE
BRIEFLY REDUCED VISIBILITIES TO BELOW ONE MILE. IN ADDITION TO THE
SNOW, THERE HAVE BEEN UPSTREAM REPORTS OF FREEZING DRIZZLE.
CORRELATION COEFFICIENT DATA FROM RADAR SUGGESTS POCKETS OF
FREEZING DRIZZLE ARE MIXING IN, PARTICULARLY WITHIN AREAS OF
WEAKER REFLECTIVITY WHERE ICE CRYSTAL GROWTH MAY BE LACKING ALOFT.
THIS WINTRY MIX HAS NECESSITATED A SPECIAL WEATHER STATEMENT FOR
SLIPPERY ROAD CONDITIONS AND MINOR ICE/SNOW ACCUMULATIONS UP TO A
HALF INCH. THIS PRECIPITATION SHIELD IS EXPECTED TO EXIT THE LAKE
MICHIGAN SHORELINE AROUND 6 PM THIS EVENING.
BEHIND THE FRONT, A STRONG RIDGE OF ARCTIC HIGH PRESSURE IS
BUILDING ACROSS THE NORTHERN PLAINS, USHERING IN MUCH COLDER AIR
ON GUSTY NORTHWEST WINDS. THIS ARCTIC HIGH WILL DOMINATE THE
WEATHER PATTERN THROUGH THE WEEKEND, KEEPING THE REGION COLD AND
LARGELY DRY. BY EARLY NEXT WEEK, THE HIGH SHIFTS EAST, ALLOWING
UPPER-LEVEL FLOW TO BECOME MORE ZONAL. THIS WILL SET THE STAGE FOR
A WARMING TREND AND THE APPROACH OF A FAST- MOVING LOW PRESSURE
SYSTEM BY WEDNESDAY NIGHT.
BITTER COLD TEMPERATURES AND WIND CHILLS:
THE PRIMARY FORECAST CONCERN IN THE SHORT TERM REVOLVES AROUND THE
ARRIVAL OF A BITTERLY COLD ARCTIC AIRMASS. BEHIND THE DEPARTING
COLD FRONT, TEMPERATURES ARE FORECAST TO PLUNGE TONIGHT. LOWS ARE
EXPECTED TO FALL MAINLY INTO THE 5 BELOW TO 13 BELOW ZERO RANGE.
THE PRESSURE GRADIENT BETWEEN THE DEPARTING LOW AND THE
APPROACHING HIGH WILL MAINTAIN A GUSTY WEST-NORTHWEST WIND
OVERNIGHT. THIS COMBINATION OF COLD TEMPERATURES AND WIND WILL
DRIVE WIND CHILL VALUES DOWN INTO THE 20 BELOW TO 30 BELOW ZERO
RANGE AFTER MIDNIGHT THROUGH SATURDAY MORNING. WHILE A FEW
LOCATIONS COULD BRIEFLY TOUCH 35 BELOW, THE COVERAGE OF EXTREME
COLD WARNING CRITERIA DOES NOT LOOK WIDESPREAD ENOUGH TO UPGRADE
HEADLINES AT THIS TIME. A COLD WEATHER ADVISORY IS IN EFFECT FOR
MOST OF THE AREA STARTING TONIGHT.
SATURDAY WILL OFFER LITTLE RELIEF, WITH HIGH TEMPERATURES STRUGGLING
TO REACH ZERO TO 5 DEGREES ABOVE ZERO, THOUGH DOOR COUNTY MAY SEE
SLIGHTLY WARMER READINGS. DESPITE SOME SUNSHINE, WIND CHILLS ARE
EXPECTED TO HOVER BETWEEN 15 AND 25 BELOW ZERO DURING THE AFTERNOON
BEFORE DROPPING AGAIN IN THE EVENING. CONSEQUENTLY, THE WIND CHILL
ADVISORY HAS BEEN EXTENDED THROUGH THE DAY SATURDAY FOR CENTRAL AND
EAST-CENTRAL WISCONSIN. A TRAILING SHORTWAVE TROUGH DROPPING SOUTH
SATURDAY NIGHT WILL VEER WINDS TO THE NORTH, POTENTIALLY BRINGING
CLOUDS OFF LAKE SUPERIOR INTO NORTHERN WISCONSIN. THESE CLOUDS
HAVE POTENTIAL TO PROP UP TEMPS SOMEWHAT BUT COVERAGE WILL BE
DIFFICULT TO FORECAST. THEREFORE, NO CHANGES TO THE COLD WEATHER
ADVISORIES SEEM WARRANTED.
THE ARCTIC AIRMASS BEGINS TO MODIFY ON SUNDAY AS THE CORE OF THE
COLD AIR SHIFTS EAST, ALLOWING HIGHS TO RECOVER INTO THE SINGLE
DIGITS AND TEENS.
LIGHT WINTRY PRECIPITATION IMPACTS THIS WEEKEND:
NORTHERLY FLOW BEHIND THE SATURDAY NIGHT SHORTWAVE COULD GENERATE
LAKE EFFECT CLOUDS AND PERHAPS SOME LIGHT SNOW OR FLURRIES NEAR
THE UPPER PENINSULA BORDER, BUT SIGNIFICANT ACCUMULATION IS NOT
EXPECTED.
MID-WEEK SYSTEM AND WARMING TREND:
ATTENTION SHIFTS TO A PATTERN CHANGE FOR THE MIDDLE OF NEXT WEEK.
AS THE ARCTIC HIGH RETREATS INTO CANADA, SOUTHWESTERLY FLOW WILL
BECOME ESTABLISHED, ADVECTING WARMER AIR INTO THE WESTERN GREAT
LAKES. HIGH TEMPERATURES ARE FORECAST TO REBOUND INTO THE 30S BY
TUESDAY AND WEDNESDAY. FORECAST MODELS ARE SHOWING A FAST-MOVING
AND POTENT CYCLONE PROGGED TO CROSS LAKE SUPERIOR WEDNESDAY NIGHT.
THIS TRACK PLACES THE FORECAST AREA IN THE WARM SECTOR FOR A
TIME. CRITICAL THICKNESS VALUES ARE PROJECTED TO LIFT NORTH OF THE
UPPER PENINSULA BORDER BY WEDNESDAY EVENING, AND SURFACE
DEWPOINTS ARE EXPECTED TO RISE ABOVE FREEZING ACROSS SOUTHERN
PORTIONS OF THE AREA.
THIS THERMAL PROFILE SUPPORTS A TRANSITION TO A WINTRY MIX OR EVEN
RAIN WEDNESDAY NIGHT. HOWEVER, WITH THE GROUND REMAINING VERY COLD
FROM THE PRECEDING ARCTIC OUTBREAK, ANY LIQUID PRECIPITATION PRECIP
WILL HAVE THE POTENTIAL TO FREEZE UPON CONTACT, CREATING HAZARDOUS
TRAVEL CONDITIONS. ADDITIONALLY, THE ADVECTION OF HIGHER DEWPOINT
AIR OVER THE COLD SNOWPACK COULD LEAD TO THE DEVELOPMENT OF DENSE
FOG OVER SOUTHERN SECTIONS OF THE FORECAST AREA. AS THE SYSTEM
DEPARTS ON THURSDAY, THERE ARE SIGNALS FOR A PERIOD OF WINDY
CONDITIONS AS COLDER AIR WRAPS BACK INTO THE REGION. THERE IS
STILL SIGNIFICANT SPREAD IN MODEL GUIDANCE REGARDING THE MAGNITUDE
OF THE COLD AIR RETURNING LATE NEXT WEEK.
AVIATION
FOR 06Z TAF ISSUANCE
ISSUED AT 1129 PM CST FRI DEC 12 2025
CLEARING SKIES WILL LEAD TO WIDESPREAD VFR CONDITIONS ACROSS ALL
TAF SITES FOR THE REST OF THE OVERNIGHT HOURS AND INTO SATURDAY.
GUSTY NORTHWEST WINDS ARE EXPECTED, WITH SUSTAINED WINDS OF 10-15
KNOTS AND GUSTS OF 20-25 KNOTS THROUGH THE WEEKEND.
GRB WATCHES/WARNINGS/ADVISORIES
COLD WEATHER ADVISORY UNTIL 10 AM CST SATURDAY FOR WIZ005-
010>013-021-073-074.
COLD WEATHER ADVISORY UNTIL 10 AM CST SUNDAY FOR WIZ018>020-030-
031-035>040-045-048>050.
DISCUSSION.....MPC
AVIATION.......KURIMSKI
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