746
FXUS63 KGRB 172339
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
539 PM CST MON FEB 17 2025
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
KEY MESSAGES
- BITTERLY COLD WIND CHILLS ARE EXPECTED THROUGH MID-WEEK. THE
COLDEST READINGS ARE EXPECTED LATE TONIGHT INTO TUESDAY MORNING,
WITH WIND CHILLS AS LOW AS 25 TO 35 BELOW ZERO. EXTREME COLD
WARNINGS AND COLD WEATHER ADVISORIES ARE IN EFFECT. ADDITIONAL
COLD WEATHER HEADLINES MAY BE NEEDED TUESDAY NIGHT INTO
WEDNESDAY MORNING.
- A LESS ACTIVE WEATHER PATTERN THIS WEEK WILL LEAD TO MINIMAL
CHANCES FOR ACCUMULATING SNOW.
DISCUSSION
ISSUED AT 307 PM CST MON FEB 17 2025
SHORT TERM...TONIGHT AND TUESDAY
THE BITTERLY COLD TEMPERATURES AND DANGEROUSLY COLD WIND CHILLS ARE
THE MAIN FOCUS FROM THIS FORECAST PERIOD. EXTREME COLD WARNINGS AND
COLD WEATHER ADVISORIES HAVE BEEN ISSUED FROM 9 PM TONIGHT THROUGH
10 AM TUESDAY.
TEMPERATURES/WIND CHILLS...CYCLONIC FLOW HAS ALLOWED A BITTERLY COLD
AIR MASS ASSOCIATED WITH A SURFACE HIGH PRESSURE SYSTEM TO SPREAD
OVER THE REGION TODAY. THIS PATTERN WILL CONTINUE TONIGHT INTO
TUESDAY. AS A RESULT, MOSTLY CLEAR SKIES ARE EXPECTED OVERNIGHT,
WITH THE EXCEPTION IN FAR NORTH-CENTRAL WI, WHERE LAKE-EFFECT CLOUDS
WILL LINGER. WITH THE COLD AIR MASS STILL IN PLACE, BITTERLY COLD
TEMPERATURES ARE EXPECTED TONIGHT WITH LOWS RANGING FROM AROUND 5 TO
10 BELOW IN FAR NORTHEAST WI, TO 10 TO 20 BELOW ELSEWHERE. THE
COLDEST TEMPERATURES ARE ANTICIPATED IN CENTRAL WI. IN ADDITION TO
THE COLD AIR TEMPERATURES, W-NW WINDS OF 5 TO 10 MPH WILL GENERATE
DANGEROUSLY COLD WIND CHILLS OVERNIGHT INTO TUESDAY MORNING. WIND
CHILLS AS COLD AS 30 TO 35 BELOW ZERO ARE ANTICIPATED, WITH THE
COLDEST WIND CHILLS IN CENTRAL WI WHERE AN EXTREME COLD WARNING HAS
BEEN ISSUED. COLD WEATHER ADVISORIES ARE IN EFFECT ELSEWHERE. A FEW
SITES ACROSS THE FOX VALLEY MAY BRIEFLY SEE WARNING CRITERIA (WIND
CHILLS OF -30), BUT OPTED NOT TO INCLUDE THEM IN THE WARNING DUE TO
HOW BRIEF THESE CONDITIONS WOULD OCCUR.
THE BITTER COLD CONTINUES ON TUESDAY WITH HIGH TEMPERATURES ONLY A
COUPLE DEGREES HIGHER THAN MONDAY'S HIGHS. HIGHS TO RANGE FROM THE
SINGLE DIGITS ABOVE ZERO AT MOST LOCATIONS, TO THE LOW 10S IN FAR
NORTHEAST WI. W-NW WINDS OF 5 TO 15 MPH WILL RESULT IN DAYTIME WIND
CHILLS IN THE SINGLE DIGITS BELOW ZERO.
LIGHT SNOW CHANCES...DUE TO THE PREVAILING CYCLONIC FLOW, NORTHWEST
WINDS WILL GENERATE LIGHT LAKE-EFFECT SNOW SHOWERS IN FAR NORTH-
CENTRAL WI OFF OF LAKE SUPERIOR THROUGH LATE TONIGHT. ANY SNOW
ACCUMULATIONS WILL BE CONFINED TO THE WI/UPPER MI BORDER WITH ONLY A
DUSTING TO A COUPLE TENTHS EXPECTED.
LONG TERM...TUESDAY NIGHT THROUGH MONDAY
DEEP UPPER LEVEL TROUGHING WILL KEEP COLD AIR ACROSS THE REGION
MOST OF THIS WEEK. ONCE ARCTIC HIGH PRESSURE 1050+ MB FROM CENTRAL
CANADA TO THE NORTHERN PLAINS EARLY THIS WEEK SHIFTS TO THE OHIO
VALLEY/SOUTHEAST US LATE THIS WEEK, WE'LL BEGIN TO SEE RETURN FLOW
PATTERN DEVELOP WITH WARMER AIR RETURNING TO THE WESTERN GREAT
LAKES REGION. THE BROAD ARCTIC HIGH AND UPPER TROUGH WILL KEEP
ACTIVE WEATHER PATTERN TO THE SOUTH FROM THE SOUTHERN PLAINS TO
THE OHIO VALLEY. THERE WILL BE TWO PRIMARY CHANCES FOR SOME LIGHT
SNOW; WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT, THEN AGAIN THIS
COMING WEEKEND. AS OF RIGHT NOW, THE PROBABILITIES FOR EVEN AN
INCH OF SNOW EITHER OF THESE TIME FRAMES REMAINS QUITE LOW.
LINGERING COLD AND VERY COLD WIND CHILLS THEN WARMING INTO THE
WEEKEND...LAST VERY COLD NIGHT IS TUESDAY NIGHT. CONTINUE TO
FAVOR LOWER END OF GUIDANCE, BUT NOT COMPLETELY DOWN TO THE LOWEST
10TH PERCENTILE GIVEN THERE WILL STILL BE SOME WIND AS PRESSURE
GRADIENT IS STILL PRESENT WITH HIGH CENTER OVER NORTHERN PLAINS
AND SYSTEM CROSSING CENTRAL AND SOUTHERN MISSISSIPPI RIVER VALLEY.
RESULT IS MIN TEMPS 10 BELOW TO NEAR 20 BELOW OVER CENTRAL
WISCONSIN, WITH READINGS 2 TO 8 BELOW ZERO INTO NORTHEAST AND
EAST-CENTRAL WISCONSIN. WIND CHILL READINGS MEET CRITERIA FOR
ADVISORY OVER CENTRAL WISCONSIN, BUT WILL BE MORE MARGINAL
ELSEWHERE. SUB ZERO MIN TEMPS STILL EXPECTED WEDNESDAY NIGHT AND
THURSDAY NIGHT, BUT WITH MINIMAL WIND, APPARENT TEMPS DO NOT LOOK
TO JUSTIFY ANY FURTHER COLD WEATHER HEADLINES.
WARMER TEMPS, OR AT LEAST NOT AS COLD, ARRIVE LATE THIS WEEK AS
RETURN FLOW PATTERN BEGINS TO DEVELOP. HIGH TEMPS THURSDAY AND
FRIDAY WILL BE CLOSER TO NORMAL AS READINGS REACH THE LOW TO MID
20S. HIGHS WARM FURTHER FOR THE WEEKEND, WITH READINGS NEAR NORMAL
ON SATURDAY AND REACHING THE 30S ON SUNDAY.
SMALL SNOW CHANCES...A FEW FLURRIES MAY BE FLYING ACROSS VILAS
COUNTY TUESDAY NIGHT WITH CONVERGENT NW FLOW OFF LAKE SUPERIOR.
ON WEDNESDAY, AS SHORTWAVE TROUGH DIVES ACROSS UPPER MISSISSIPPI
RIVER VALLEY AND LOW-LEVEL LAPSE RATES STEEPEN DURING PEAK
HEATING, MAY SEE SOME ADDITIONAL SNOW SHOWERS AND FLURRIES ALONG
AND NORTH OF HIGHWAY 29. LATE WEDNESDAY INTO WEDNESDAY NIGHT, WEAK
TROUGH MOVING NORTH-SOUTH RESULTS IN NORTHERLY FLOW BRINGING LIGHT
LAKE EFFECT TO NORTH CENTRAL WISCONSIN AND POTENTIALLY THE LAKE
MICHIGAN SHORELINE. SMALL RISK THAT A COUPLE INCHES OF SNOW COULD
OCCUR NEAR LAKE MICHIGAN, BUT STILL APPEARS GREATER POTENTIAL FOR
LAKE ENHANCEMENT WILL BE AT THE SOUTH END OF LAKE MICHIGAN.
OTHER SMALL SNOW CHANCES COULD COME AS EARLY AS FRIDAY NIGHT AS
THE WARMER AIR MOVES IN FIRST ALOFT, BUT COULD OCCUR AS LATER AS
SUNDAY INTO MONDAY. TEMPERATURES ON MONDAY WILL BE WARM ENOUGH TO
SUPPORT MIXED RAIN/SNOW IF PRECIPITATION OCCURS. RIGHT NOW, ANY
SNOWFALL LOOKS VERY LIGHT.
AVIATION
FOR 00Z TAF ISSUANCE
ISSUED AT 538 PM CST MON FEB 17 2025
NORTHWEST WINDS FLOWING OVER LAKE SUPERIOR WILL CONTINUE TO
PRODUCE HIGH-END MVFR TO LOW-END VFR CLOUDS ACROSS NORTHERN WI THIS
EVENING INTO TUESDAY. SOME LIGHT SNOW SHOWERS OR FLURRIES ARE
ALSO POSSIBLE AS WELL, BUT WILL LIKELY STAY NORTH OF RHI.
OTHERWISE, VFR CONDITIONS ARE EXPECTED.
WEST-NORTHWEST WINDS WILL CONTINUE THROUGH THE TAF PERIOD. GUSTS
UP TO 15-20 KTS WILL CONTINUE LATE THIS AFTERNOON, THEN SUBSIDE
TO MAINLY UNDER 10 KTS THIS EVENING, BUT A FEW GUSTS TO ~15 KTS
ARE POSSIBLE OVERNIGHT AND AGAIN ON TUESDAY.
GRB WATCHES/WARNINGS/ADVISORIES
COLD WEATHER ADVISORY FROM 9 PM THIS EVENING TO 10 AM CST
TUESDAY FOR WIZ005-010>013-020>022-031-037>040-048>050-073-074.
EXTREME COLD WARNING FROM 9 PM THIS EVENING TO 10 AM CST TUESDAY
FOR WIZ018-019-030-035-036-045.
DISCUSSION.....KRUK/JLA
AVIATION.......BERSCH
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