057
FXUS63 KGRB 211737
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1137 AM CST TUE JAN 21 2025
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE
KEY MESSAGES
- DANGEROUSLY COLD WEATHER IS EXPECTED THIS MORNING. WIND CHILLS
WILL RANGE FROM 25 TO 45 BELOW ZERO IN CENTRAL AND NORTH-
CENTRAL WISCONSIN AND 20 TO 35 BELOW ZERO ELSEWHERE. EXTREME
COLD WARNINGS ARE IN EFFECT FOR THE ENTIRE AREA THROUGH NOON.
- COLD WEATHER IS EXPECTED TO CONTINUE THIS AFTERNOON AND THIS
EVENING. WIND CHILLS WILL GENERALLY RANGE FROM 20 TO 35 BELOW
ZERO. COLD WEATHER ADVISORIES ARE IN EFFECT FOR THE ENTIRE AREA
FROM NOON UNTIL MIDNIGHT.
- AFTER TONIGHT, ONE LAST COLDER NIGHT IS IN THE FORECAST FOR
THURSDAY NIGHT BEFORE A WARMING TREND ARRIVES AND LASTS THROUGH
THE WEEKEND.
DISCUSSION
ISSUED AT 319 AM CST TUE JAN 21 2025
SHORT TERM...TODAY...TONIGHT...AND WEDNESDAY
AN ARCTIC AIRMASS COMBINED WITH LIGHT WINDS HAS CAUSED VERY COLD
WIND CHILLS ACROSS THE REGION EARLY THIS MORNING OF 25 TO 40 BELOW
ZERO. ALTHOUGH TEMPERATURES SHOULD RISE A FEW DEGREES AS THE SUN
COMES UP, THE INCREASE IN WIND AS THE BOUNDARY LAYER DECOUPLES
WILL KEEP THE VERY COLD WIND CHILLS IN PLACE THROUGH MUCH OF THE
MORNING. THEREFORE, WILL KEEP THE EXTREME COLD WARNING IN EFFECT
FOR THE ENTIRE REGION THROUGH NOON WHEN SURFACE TEMPERATURES
SHOULD WARM ENOUGH TO OVERCOME THE GUSTY WINDS BY THIS AFTERNOON.
ALTHOUGH WIND CHILLS WILL RISE THIS AFTERNOON, THEY WILL STILL
LIKELY HIT COLD WEATHER ADVISORY CRITERIA AS HIGHS TODAY ARE ONLY
EXPECTED TO RISE TO AROUND ZERO ACROSS CENTRAL AND EAST-CENTRAL
WISCONSIN AND THE SINGLE DIGITS BELOW ZERO ACROSS NORTH-CENTRAL
WISCONSIN.
A CLIPPER SYSTEM APPROACHING FROM THE WEST WILL CAUSE SURFACE
WINDS TO TURN SOUTHERLY THIS EVENING, WITH TEMPERATURES WARMING
THROUGHOUT THE OVERNIGHT HOURS. LOWS TONIGHT SHOULD OCCUR EARLY IN
THE EVENING BEFORE WARM AIR ADVECTION COMMENCES, AS THE REGION
CONTINUES WITH COLD WEATHER ADVISORY CRITERIA THIS EVENING UNTIL
TEMPERATURES CAN WARM ABOVE CRITERIA. THE WARM AIR ADVECTION AHEAD
OF THE CLIPPER SYSTEM IS EXPECTED TO BEING LIGHT SNOW LATE
TONIGHT, WITH THE BEST CHANCE (30-40 PERCENT) ACROSS CENTRAL AND
NORTH-CENTRAL WISCONSIN. SNOWFALL AMOUNTS TONIGHT SHOULD BE LIGHT,
WITH A DUSTING OR A FEW TENTHS OF AN INCH POSSIBLE. LOWS THIS
EVENING ARE EXPECTED TO BOTTOM OUT TO AROUND 10 BELOW ZERO ACROSS
NORTH-CENTRAL AND THE SINGLE DIGITS BELOW ZERO ACROSS THE REST OF
THE REGION BEFORE WARMING AS THE NIGHT WEARS ON.
THE CLIPPER WILL CONTINUE TRACKING TOWARDS THE AREA DURING THE DAY
ON WEDNESDAY AS TEMPERATURES WARM ACROSS THE REGION. HIGHS ON
WEDNESDAY ARE EXPECTED TO SOAR INTO THE MIDDLE TEENS ACROSS THE
NORTH, WITH HIGHS AROUND 20 ACROSS CENTRAL AND EAST-CENTRAL
WISCONSIN. LIGHT SNOW WILL CONTINUE TO FALL WITH MODEST BROAD
FRONTOGENESIS AND MOISTURE. SNOWFALL AMOUNTS WILL AGAIN GENERALLY
BE A DUSTING TO A FEW TENTHS OF AN INCH AS THE PROBABILITY OF
REACHING OR EXCEEDING 1 INCH IS RATHER LOW (AT MOST 10 PERCENT).
LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY
THE EXTENDED FORECAST WILL FOCUS ON SOME LINGERING COLD AIR ALONG
WITH A FEW CHANCES FOR SOME LIGHT SNOW IN THE FORECAST.
TEMPS/WIND CHILLS...
AFTER A RELATIVE WARMUP IN THE MIDDLE OF THE WEEK AND LOW
TEMPERATURES STAYING ABOVE ZERO WEDNESDAY NIGHT, ANOTHER PUSH OF
COLDER AIR WILL BE POSSIBLE THURSDAY NIGHT AS WEAK COLD AIR
ADVECTION AND CLEARING SKIES ALLOW TEMPERATURES TO DROP BELOW
ZERO BY FRIDAY MORNING ACROSS THE NORTHWOODS. CURRENT
PROBABILISTIC GUIDANCE BRINGS AROUND A 50% CHANCE OF GETTING TO
-20 ACROSS PORTIONS AND NORTH-CENTRAL WISCONSIN ONLY AROUND 10-15%
CHANCE TO GET AS LOW AS -25, SO WHILE THIS WILL BE ANOTHER
RELATIVELY COLDER NIGHT, DON'T CURRENTLY ANTICIPATE COLD WEATHER
HEADLINES.
BEHIND THIS BRIEF COLDER PERIOD TEMPERATURES ARE GENERALLY
EXPECTED TO MODERATE AGAIN THROUGH THE WEEKEND WITH OVERNIGHT
TEMPERATURES STAYING ABOVE ZERO AND DAYTIME HIGHS GETTING BACK
INTO THE 20S AND POSSIBLY A FEW LOWER 30S BY EARLY NEXT WEEK.
LIGHT SNOW CHANCES...
IN GENERAL THE EXTENDED PERIOD WILL BE FAIRLY DRY. THE ONLY
POTENTIAL FOR ANY PRECIPITATION WILL BE SOME LINGERING SNOW
SHOWERS WEDNESDAY NIGHT AND THEN ANOTHER CHANCE FOR SOME LAKE
EFFECT ACROSS NORTHERN WISCONSIN DURING THE WEEKEND.
AVIATION
FOR 18Z TAF ISSUANCE
ISSUED AT 1137 AM CST TUE JAN 21 2025
MAIN AVIATION ELEMENTS WILL BE SURFACE WINDS AND LLWS. WEST WINDS
ARE IN SOMEWHAT OF A LULL AS OF 1730Z, BUT AS WINDS BACK SW TO S
EXPECT GUSTS TO INCREASE 20-25 KTS GUSTS TO BECOME MORE
WIDESPREAD. ADDITIONALLY, WINDS AROUND 40KTS AT 2KFT WILL CREATE
LLWS FROM ABOUT 03Z/WED TO 18Z/WED.
SKIES WILL REMAIN MAINLY CLEAR THIS AFTERNOON, WITH MID AND HIGH
CLOUDS ARRIVING THIS EVENING AHEAD OF A CLIPPER SYSTEM. THIS
SYSTEM WILL ALSO BRING SCATTERED, LIGHT SNOW LATE TONIGHT AND
WEDNESDAY. CONFIDENCE IN PREVAILING SNOW AT ANY ONE SITE IS LOW,
SO INCLUDED TEMPO GROUPS TO HIGHLIGHT THE MOST LIKELY TIME WINDOW
FOR LIGHT SNOW. IMPACTS WILL BE MINIMAL, BUT BRIEF DIPS TO MVFR
CONDITIONS ARE POSSIBLE. AT THE MOMENT, EXPECTING MAINLY VFR TO
PREVAIL.
GRB WATCHES/WARNINGS/ADVISORIES
EXTREME COLD WARNING UNTIL NOON CST TODAY FOR WIZ005-010>013-
018>022-030-031-035>040-045-048>050-073-074.
COLD WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ005-
010>013-018>022-030-031-035>040-045-048>050-073-074.
DISCUSSION.....KURIMSKI/UHLMANN
AVIATION.......KLJ
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